[HN Gopher] Runway melts at London Luton airport as temperatures...
___________________________________________________________________
Runway melts at London Luton airport as temperatures in UK near
40degC
Author : russfink
Score : 231 points
Date : 2022-07-19 14:20 UTC (8 hours ago)
(HTM) web link (www.dailytelegraph.com.au)
(TXT) w3m dump (www.dailytelegraph.com.au)
| hotz wrote:
| sdrwefgfvb wrote:
| 12ian34 wrote:
| Tell that to the people whose homes have been destroyed. or
| perhaps all the people that have died in these conditions. It's
| not typical in the UK. Imagine if you had to emergency evacuate
| your home for some natural disaster that you'd never have
| imagined was possible where you live. Would you really be so
| cavalier? Would you really say this?
| saberience wrote:
| This is an idiotic comment. As a British person, for most of my
| lifetime it was a shock to get 30+ temperatures in the UK and
| if you got multiple 30+ days in a row it was newsworthy. Also,
| 99.99% of people in the UK don't have fans at home, let alone
| AC, it simply has never been needed.
|
| So yes, a 40 degrees C day in the UK is insane news, especially
| given it's about a degree and a half hotter than the previous
| all-time record!
| techwiz137 wrote:
| You will be seeing 50c very soon, just as we saw 46c and have
| been seeing 40c for years, I am surprised nobody prepared for
| this.
| masklinn wrote:
| It's the first time since records started that 40C has been
| reached in the UK. Before today it was quite literally not a
| thing that happened.
|
| The average high temp of a london summer is 24C.
|
| This is not a "summer is hot" situation, this is a "country has
| never planned and is not prepared for" situation.
| secretsatan wrote:
| Wow, really insightful comment right here, brilliant
| observation. Do you all get it? The commenter is pointing out
| how we have seasons in the uk, and they are absolutely
| unchanged, this is all totally normal in the uk! Brilliant!
| 12ian34 wrote:
| Even more unusual are the grass fires so close to London.
|
| Seeing people's homes destroyed is so tragic, particularly as I
| bet they would never have thought this would be an issue here in
| the UK.
|
| Sky News have some astounding[0] footage[1]:
|
| [0]: https://www.youtube.com/watch?v=7NP7GF8xS5g
|
| [1]: https://www.youtube.com/watch?v=TjBV4R18ICY
|
| ...and before the rest of you jump in saying this is regular in
| your country, please note that it is NOT regular here in the UK.
| Today, the UK has seen the highest temperature in ITS recorded
| history.
| nigerian1981 wrote:
| While the right wing media in the UK ignored the climate crisis
| in their coverage and instead focused on the "positive" side
| with front pages full of children eating ice cream and people
| at the beach.
| nicky0 wrote:
| Weather is not climate though.
| eurasiantiger wrote:
| It really isn't. People commonly think that the climate
| warming by a degree means that the weather warms up by a
| degree.
|
| However, there's a good 100 miles of air above us, and that
| mass of air warming by a degree means that it can now
| retain a LOT more humidity before it starts precipitating
| as rain.
|
| This means coastal areas get drier and hotter, while
| mountaineous areas get much more rainfall (and more of it
| as water instead of snow), as well as flooding, mudslides,
| etc.
| russfink wrote:
| But a lawn fire is not directly temperature related, is it? I
| suspect the grass has dried from lack of rain, such that some
| small spark that would ordinarily have fizzled has taken hold.
| secretsatan wrote:
| It's not like it would dry out quicker
| quarterdime wrote:
| As a former wildland fire fighter, I can assure you that
| temperature (and wind and relative humidity) have a HUGE
| effect on fire behavior. Furthermore temperature and relative
| humidity (not so much wind) have a huge impact on ignition.
| My training emphasized this quite heavily, but I thought the
| effect was exaggerated until I experienced it first hand.
|
| In the Western US, construction, mining, forestry, etc.
| industries are well aware of the fire risk from routine work
| (construction equipment, off road vehicle traffic, chain saw
| work, etc.). In "red flag" conditions, there are fire watch
| policies. For example in forestry work, my crew would have to
| cease chain saw work late in the morning and stand a fire
| watch for 30 minutes before leaving the work site.
|
| So as I watch the news about these fires, my first thought is
| ignitions: routine activities (parking a vehicle on grass,
| driving construction equipment, discarding a cigarette) that
| would be unlikely to cause a fire in normal (backward
| looking) UK weather conditions. My next thought is that once
| a fire has started, it is likely to burn hot and fast. Hotter
| and faster than I suspect fire fighters in London are
| accustomed to.
|
| As an aside, I have been trying to figure out a good source
| for weather data. I see plenty of sources for temperature,
| but I am curious about the wind speeds and relative humidity.
| From the photos I am seeing, it looks like wind speeds are
| over 10 mph.
| more_corn wrote:
| ^ this is why we come to hacker news. Deep contextual
| comments from knowledgeable professionals. Thank you.
| russfink wrote:
| Agreed!
| cmroanirgo wrote:
| In Australia during droughts there are reminders to not
| throw cigarette butts out the window of cars. Lightning
| also plays a large role in starting fires, but I also
| recall, as a child, being told that rubbish (litter) such
| as bottles and cans can reflect the harsh sunlight in a
| focused way and cause an ember.
|
| I recall _not_ buying a diesel mazda car because it had a
| disclaimer about not parking on long grass because of the
| danger of starting a fire. Apparently, mazda finally made
| it to recall status:
|
| https://www.abc.net.au/news/rural/2017-12-29/ford-rangers-
| ma...
|
| From the owner's manual[?]
|
| > _Parking over or near anything flammable, such as dry
| grass, is dangerous._
|
| https://owners-
| manual.mazda.com/gen/en/cx-5/cx-5_8gj1ee18b/c...
| aeroman wrote:
| You could try the Met Office website. This is a station in
| North West London
|
| https://www.metoffice.gov.uk/weather/observations/gcpvj0v07
|
| Humidity was about 15-20% during the afternoon, winds 13
| gusting 26mph.
| adhesive_wombat wrote:
| It was very strange this afternoon to have such a strong
| wind (29mph here, not in London) that was so hot (39C) I
| have never felt anything like it in the UK, it was like
| standing in front of a giant hairdryer.
| maigret wrote:
| The lack of rain comes from the same climate emergency
| though, this has been confirmed scientifically as well.
| salt-thrower wrote:
| Not sure why you're being downvoted. Weather patterns like
| droughts are exacerbated by climate change. Heat waves are
| known to make it easier for fires to catch and spread. Heat
| waves are more common now due to climate change. Thus
| climate change makes fires more likely/common. It's pretty
| straightforward.
| maigret wrote:
| Yeah the jet stream is clearly slowing down because the
| temperature difference with the arctic is lower than
| before. But to be honest I don't care much about my karma
| here. Thanks for the nice answer in any case
| WalterBright wrote:
| Please don't care about karma, as catering to it will
| make your posts less interesting.
| feet wrote:
| They're likely getting down voted because climate change
| deniers want to ignore the evidence that's beginning to
| scream at us
| maigret wrote:
| That's a good point though. Many tell lobbies are at
| work, but I think many people can't take such a harsh
| change, and I can understand that. We have to focus on
| changing step by step. The level at which renewables are
| taking over in many countries is giving me hope.
| danans wrote:
| > But a lawn fire is not directly temperature related, is it?
|
| The rate of evaporation is directly related to the
| temperature. Even ignoring additional factors affecting
| evaporation like wind and topographic variance in dryness,
| the vapor pressure of water (the biggest contributor to
| evaporation rate) at 40C is an order of magnitude higher than
| it is at 20C:
|
| https://en.wikipedia.org/wiki/Evaporation#/media/File:Water_.
| ..
|
| Sufficient subsequent days of high heat and low humidity will
| dry out a lawn very quickly, as grass is a plant that is not
| adapted to retain moisture very well.
|
| With hot/dry enough conditions for a sufficient period of
| time and a bit of kinetic energy in the form of wind, grass
| that isn't watered quickly becomes flammable, which is why it
| is usually where large fires first take hold.
| retard111 wrote:
| danans wrote:
| I expect that much infrastructure designed for a previous set of
| worst case scenarios is going to experience failures, especially
| older and poorly maintained infrastructure.
|
| Hopefully many of them can be managed like when the event occurs.
| However, some of them like seawalls may fail during single
| catastrophic weather events.
| [deleted]
| seydor wrote:
| More like runnyway. This is bad engineering
| turbonaut wrote:
| Failure or going temporarily out of use does not necessarily
| imply bad engineering. Engineering also has to assess the cost
| of a solution and weigh this against the risk and impact of any
| failures. In this case the prior on risk of a 'melting event'
| may have gone up since the runway was designed. The impact of
| closing for one day in x years may also have been explicitly
| deemed acceptable.
| cardiffspaceman wrote:
| Illustrating that design isn't always 7-sigma availability,
| There's a shopping mall parking garage near here that is
| essentially the river bank. When the river runs a high flood,
| the waters are intended to inundate a lot of parking spaces,
| to avoid overly-confining those waters. And it's deep enough
| that some of the parked cars float. Also this parking garage
| replaced a surface parking lot that was doing the same thing.
| The second level of the parking garage is not supposed to be
| inundated, so the garage is a lot taller than it would have
| been for the same capacity. One can see flood stains on the
| walls of the first level.
|
| The alternative would have been to build levees to confine
| the waters to a channel, and hope the channel was deep
| enough.
| pixl97 wrote:
| Right. Just like homes in the southern US would stand up to 36"
| of snow load without issue.....
| smcl wrote:
| Yep and not just homes, power grid, roads ... everything.
| People joke that the south of England "shuts down" when
| there's snow, and while there are services that suffer it's
| never quite like how badly Texas collapsed during their big
| storm.
|
| When there are extreme weather events that you've not
| planned, designed and built your infrastructure for, you're
| basically at the mercy of mother nature. In the UK's case
| that's extremely hot weather, in Texas' case that was extreme
| cold
| fingerlocks wrote:
| Same occurance on the M25 in 2003.
|
| https://en.m.wikipedia.org/wiki/2003_European_heat_wave#Unit...
| xattt wrote:
| Toronto has certainly had 40deg days and there were no concerns
| at the time with the runways melting.
| floatrock wrote:
| Great, sounds like you engineered things for your expected
| temperature ranges.
|
| Story here is a major piece of infrastructure is experiencing
| temperatures outside of its designed-for temperature range.
| jacquesm wrote:
| Toronto is interesting in that it has to deal with a fairly
| extreme range of temperatures between summer and winter, in
| the UK the spread is much more narrow (or at least, it was).
| kennend3 wrote:
| As someone who lives in the GTA...
|
| Your post doesn't make sense for two reasons.
|
| 1) Toronto airport was built to withstand these temperatures as
| we have reached them before. Basically it is within the
| expected design parameters. UK's airport is experiencing
| temperatures outside its normal range.
|
| Building infra is a lot of cost/benefit analysis. Building
| runways to experience the wide temperature range Toronto faces
| is very costly.
|
| 2) A lot of our infrastructure has been impacted by "extreme
| heat" as well.
|
| How many times has GO transit issued "reduced speed"
| notifications due to track temperatures?
| xattt wrote:
| > UK's airport is experiencing temperatures outside its
| normal range
|
| This certainly seems like a case of infra debt catching up.
| tehbeard wrote:
| How is it debt to not massively overengineer?
|
| They're concern would have been handling rainfall within
| nominal temperature ranges, not building it to handle every
| possible scenario?
|
| Would you consider it tech debt if the runway structure
| failed when a UFO landed due to its exhaust causing
| resonance?
| kennend3 wrote:
| Or the classic "penny wise and pound foolish" which is
| fitting as the saying originated in the UK.
|
| Perhaps they opted to error on the side of "lets be really
| optimistic on temperature ranges and save a lot of money on
| materials"?
| Scoundreller wrote:
| The roads on the other hand...
| danbruc wrote:
| Does the title have a typo and it should be as instead of has or
| is this correct?
| smcl wrote:
| The headline is correct as written. There is an abbreviated
| grammar common in English newspaper headlines (at least in UK
| and seemingly Australia). "($thing_x occurs) as ($thing_y
| occurs)" means "$thing_x occurs, because of or related to
| $thing_y occurring".
|
| So you might also see a headline like "Dortmund's title hopes
| fade as Lewandowski scores hat-trick" => "Dortmund's chances of
| winning the Bundesliga became narrower, after Bayern won and
| Robert Lewandowski scored three goals (possibly against
| Dortmund)"
|
| It's something native speakers often don't realise, but there's
| a lot of really specific stuff for healdines
| danbruc wrote:
| X as Y is perfectly fine, but the article headline still and
| the HN title previously read X has Y. That is what I was
| wondering about, whether this is some strange headline
| shortcut.
| smcl wrote:
| OH sorry! I must have I read your comment exactly backwards
| because the headline had already been corrected :D
| mikro2nd wrote:
| Either one is correct. Meaning is subtly different, but not
| much.
| ALittleLight wrote:
| "has" is not correct it should be "as".
|
| A later sentence in the article is formed similarly and
| correctly uses "as" - "The runway also 'melted' at the RAF
| Brize Norton, military air base in Oxfordshire, west of
| London, on Monday _as_ the UK struggled to cope with the
| weather. "
| dylan604 wrote:
| But the airport can _have_ temperatures. With some
| additional punctuation, has could be read more clearly.
| ALittleLight wrote:
| Let's say "Runway melts" is X and Y is "temperatures in
| the UK near 40". "X as Y" says that these two things are
| happening at the same time. That makes sense. "X has Y"
| is incoherent.
|
| I think this matters because some people on hackernews
| are not native English users. They may be legitimately
| confused or misled by typos that a native speaker would
| unconsciously correct.
| yongjik wrote:
| As in, "melted runway at London Luton airport has gained
| sentience, named itself The Global Warming, and is holding
| the rest of the UK as hostage with its super-area-heating
| power; negotiations are ongoing"?
| anigbrowl wrote:
| That's just the regional accent.
| PaywallBuster wrote:
| Adding alternative links since site is down
|
| https://www.cbsnews.com/news/extreme-heat-in-uk-disrupts-air...
|
| https://www.theguardian.com/uk-news/2022/jul/18/uk-transport...
| russfink wrote:
| My question - how does the composition of the surface compare
| with that in other parts of the world that are hotter - Dubai,
| Saudi Arabia, Australia, the American southwest? Is there some
| code or regulation that helps these hotter places avoid this
| problem, and if so, should the UK government adopt them?
| digdugdirk wrote:
| The article mentioned a section "buckled" - this is the more
| likely outcome. When designing roads/runways, engineers design
| for the most likely thermal range. This is then used to
| determine how much expansion to account for. You'll see this
| most commonly on bridges, with sections of "teeth" that allow
| for large expansion/contraction ranges, since the bridge can't
| expand in the same way a ground road can.
|
| In this case, its likely more a matter of runways needing more
| precision, and therefore the design allowance on the range of
| extreme temps being much lower. I'm sure a civil engineer could
| explain better.
| russfink wrote:
| Aha, so perhaps the press got it wrong by saying it "melted"
| - maybe it actually buckled. They might have it confused with
| common roads that are actually softening and "melting" rather
| than buckling.
| Milner08 wrote:
| Its about building a surface that will also survive the winter
| and the summer. Its a tricky problem to solve. We could
| probably replace this with tarmac that could survive much
| hotter temps, but would just crack and break in the winter when
| its gets too cold.
| russfink wrote:
| Thank you - good explanation. There is no "one <type> fits
| all," then, for tarmac.
| badcppdev wrote:
| As well as making concrete runways the best thing the UK
| government could do is adopt a "war footing" where it comes to
| climate change.
|
| I use the term war footing because the impact of climate change
| is going to be on the order of a major war. And also because
| the response required for the decarbonisation required is going
| to be a significant portion of GDP.
|
| Or they could keep their heads in the sand.
| Synaesthesia wrote:
| The whole world needs to.
| petre wrote:
| They put more gravel inside the tarmac or use concrete.
| darksaints wrote:
| If you use a cold weather composition in hot weather, you get
| melting asphault like this. If you use a warm weather
| composition in cold weather, you get cracks and potholes
| earlier than normal. Your composition is typically defined by
| climate conditions, not weather extremes.
| russfink wrote:
| Thank you - good explanation - the problem, then, is that
| there is no "one <type> fits all" solution for tarmac. It's
| just a case of the runway being built for different
| conditions. In other words, mother nature (global warming)
| violated the design requirements.
| LightG wrote:
| There's a similar story happening with our rail lines. The
| story seems to be that the materials we used in the UK are not
| stressed to deal with 40 degree heat. They never thought it
| would be an issue in the UK. Whereas many European railway
| lines were made to deal with 40-45 degree heat. I'm guessing
| it's the same for runway tarmac or whatever it is ...
|
| Climate change is here ...
| smcl wrote:
| > There's a similar story happening with our rail lines
|
| No, there's a similar story happening with _everyone 's_ rail
| lines. There's a curious thing bout Britain where the British
| press love a hysterical "here's an example of Broken
| Britain!" headline, and Europe and America quite enjoy seeing
| the UK getting any sort of comeuppance (and normally I
| wouldn't begrudge them this, there have been a lot of insane
| goings on in the UK of late).
|
| But the only instance I've seen of this - not announcements
| of restricted services or reduced speeds as a precaution or
| due to reduce damage in overhead lines, _actual_ buckling -
| today has been in Spain:
|
| - https://twitter.com/rail_arri/status/1549039421525458945
|
| - https://twitter.com/rail_arri/status/1549034924010655745
|
| edit: and just minutes after I post this, I spot an instance
| in England from the weekend! https://twitter.com/networkrail/
| status/1548760985246261249/p...
| LightG wrote:
| Britain is broken.
|
| This isn't the place to debate it, but we're currently a
| rudderless, borderline second world country.
|
| It's going to take a generation to recover (let alone
| thrive) from what the last decade of flagshagging idiots
| have done to this once great country.
| dragonwriter wrote:
| > This isn't the place to debate it, but we're currently
| a rudderless, borderline second world country.
|
| You are teetering on the brink of alliance with the
| Soviet Union? (The first/second/third world thing
| originally referred to cold war alignment: first and
| second were US and Soviet spheres, third non-aligned;
| later first- and third-world got adopted as synonyms for
| "developed" and "less developed", but second-world is
| never used in that economic sense.)
| LightG wrote:
| Well, I'm using it in an economic and social sense.
|
| Glad I could clarify.
|
| Edit: and now my annoyance has settled down, I accept
| your correction. Thank you. Second division is more
| appropriate.
| mhandley wrote:
| It's not so much the materials - modern rail, especially for
| high speed trains is laid in long continuously welded
| sections. The track is pre-tensioned so that at cold
| temperatures as it tries to shrink it is under significant
| tension and as it warms it becomes less tensioned. The
| question is what temperature to tension it to - at some
| temperature it is no longer under tension and above that it
| becomes in compression and then you have risk of the rails
| buckling. If I recall correctly, in England the track is
| tensioned for 27C (a typical hot summers day temperatures).
| They could tension for a higher temperature, but then you
| risk rails cracking in very cold weather. So in the end it's
| a compromise, but one that was made without expecting the
| current 40C temperatures.
| jaclaz wrote:
| The relevant HN thread, a few days ago:
|
| https://news.ycombinator.com/item?id=32118818
| iggldiggl wrote:
| > at some temperature it is no longer under tension and
| above that it becomes in compression and then you have risk
| of the rails buckling. If I recall correctly, in England
| the track is tensioned for 27C (a typical hot summers day
| temperatures)
|
| While the basic gist is correct, a certain amount of
| compression is fine, too, because the trackbed _can_ resist
| a certain amount of sideways buckling force, especially
| once the track has settled in a bit. It 's only when the
| buckling forces caused by the temperature expansion and
| resultant compression exceed the sideways resistance of the
| trackbed that you get buckling.
|
| Besides, _rail_ temperatures on a hot summer day in the sun
| will definitively be higher than 27 degC - that value just
| happens to be the neutral temperature between maximum
| allowable compression and maximum allowable tension,
| whatever _those_ temperatures exactly are.
| mhandley wrote:
| Yes, exactly. And once it's in compression even at higher
| temperatures it will often be fine if left alone. This is
| why railway companies impose speed restrictions when it
| gets hot - they don't want the dynamic load of a passing
| train to exceed the ability of the track bed to resist
| buckling. Running at low speeds helps in this respect.
| Someone wrote:
| https://www.networkrail.co.uk/stories/why-rails-buckle-
| in-br... says "rail can actually be up to 20 degrees
| higher." and "For some of our track, such high
| temperatures are more than our track is designed to cope
| with", so it depends on the track, but can be around
| 50degC.
|
| A rail that's in the shade for most of the day will get
| less hot, so I expect location also influences at what
| air temperature track will buckle.
| dylan604 wrote:
| Growing up in a very country part of Texas, the road in front
| of my house changed over the years as the county would upgrade
| it. One upgrade in the 80s was a tar base with gravel rocks.
| During the summer when it would get 100+, the tar would melt
| and get stuck to everything. It is the primary reason I quit
| running around barefoot as a kid. I ran along the road with the
| melted tar, and learned a life lesson. Not only was the hot tar
| painful, it was extremely unpleasant to remove.
|
| Maybe in the 40 years since, people have figured things out
| like don't pour gravel covered tar roads in the heat?
| mulmen wrote:
| Pouring them in the heat is the best time because it's easier
| to melt the tar.
| dylan604 wrote:
| I didn't mean the physical act of pouring hot tar when
| making the road. I meany don't pour as in don't use that
| material in places where it regularly, almost set a
| calendar to it, getting hot enough to melt the material.
| mulmen wrote:
| I misread your comment and thought you were chasing the
| road crew and burning yourself on freshly laid tar. After
| re-reading I see that it was melted by the sun.
| Spooky23 wrote:
| That tar was often waste product, perhaps for processes that
| aren't happening.
|
| Not sure about your area, but in mine GE "donated" waste oil
| to counties for use on roads. Much of it was contaminated
| with nasty stuff and there are cancer clusters along these
| roads as the crushed stone and dust would get ground down and
| become airborne.
| dylan604 wrote:
| Thaks for that. Now that's a thought that's going to
| fester. None of the neighbors that I knew from back then
| nor anyone in my family got cancer, so probably shouldn't
| let it fester too long though. Phew
| rootusrootus wrote:
| Chip seal is still very common. I suspect that the reason you
| may have seen it evolve at a particular location is that the
| usage pattern of the road changed. Everything from gravel to
| asphalt to tarmac to concrete makes sense depending on what
| kind (and volume) of traffic a particular road sees.
| dylan604 wrote:
| This is exactly what happened. When my parents built the
| house and moved in, there were only a handful of houses. As
| more houses built and more traffic came from that, the
| county went through the upgrade process much like in Sims
| games.
| mcguire wrote:
| Nope!
|
| It's still the cheapest way to resurface a road.
| peapicker wrote:
| "the American southwest"
|
| Here in Denver, at least, our runways are all made of cement
| instead of tarmac. I knew one of the civil engineers who worked
| on the special blend of cement the used, and from what I
| remember of what he told me, it is much thicker than I
| expected, and has other stuff in it compared even to highway-
| grade cement to make it more durable. The freeze-thaw cycle is
| still rough on the cement, in 2007 $11 million of cement slabs
| had to be replaced due to that. The airport as a whole has
| 15,000 20-square-foot slabs across its multiple runways.
|
| Of course, one could still have buckling with cement if the
| expansion joints are too close together for the expansion of
| adjoining slabs over a certain temperature. Perhaps this is
| what actually happened here?
| macinjosh wrote:
| I am from the Denver region and from personal experience I
| know the area has a lot of Bentonite clays [0] which can
| expand as water is absorbed and contract as it dries. My
| neighborhood was built on land with a lot of this clay and
| our streets are wavy and our driveways are cracked to hell. I
| imagine they deal with similar issues at DIA.
|
| [0]: https://en.wikipedia.org/wiki/Bentonite
| peapicker wrote:
| My neighborhood is the same. The ground and site prep out
| at DIA the Civil Engineer friend told me about took things
| like that into account.
|
| I for one have had much of the cement replaced around my
| house (some more than once) and when I had the driveway
| redone, explicitly asked them to mitigate against the clay
| with whatever they had that made sense. I forget what all
| they had extra in the proposal that I approved (it was 10+
| yrs ago) but my new driveway isn't having any issue while
| some neighbor's new ones are already cracked again.
| OJFord wrote:
| > Here in Denver, at least, our runways are all made of
| cement instead of tarmac. [...] has other stuff in it
| compared even to highway-grade cement
|
| That's something that looks so different about (some/many?)
| American roads that I never twigged about until you said
| that. Roads are tarmac here too, not just runways. For some
| reason it didn't occur to me reading other comments about
| hotter places not using tarmac that it'd effect roads for
| cars too.
| wiremine wrote:
| I've flown through Dubai a few times, and I think most of their
| flights are early in the morning or at night. I don't know if
| that's for the runway or for the tires (or just heat in
| general), but I wonder if those factors played into things in
| the UK?
| ycombinete wrote:
| This definitely isn't the case, flights go all day at DXB.
| reaperducer wrote:
| _I don 't know if that's for the runway or for the tires (or
| just heat in general), but I wonder if those factors played
| into things in the UK?_
|
| Some afternoon and evening flights are sometimes cancelled at
| LAS if it's over 110deg. Something to do with the expansion
| of the fuel due to the heat, and long-distance jets can't get
| enough on board.
|
| It's in the local newspaper there occasionally, and should be
| Googleable.
| selimthegrim wrote:
| Not takeoff needing longer runways at higher temp due to
| less engine power?
| reaperducer wrote:
| That's a factor for canceling flights on smaller, lower
| range jets. The big long-distance jets have the problem I
| mentioned.
| gruturo wrote:
| It's for air temperature. Warm air is considerably less
| dense, which raises the takeoff and landing speed of planes
| (for a given weight), up to unsafe levels, in addition to
| requiring a longer runway.
| mcguire wrote:
| Mmm, density altitude... (https://www.faasafety.gov/files/g
| slac/library/documents/2011...)
| gruturo wrote:
| Indeed!
|
| I didn't want to call altitude into play since it tends
| not to vary too much between day and night in the same
| place :)
| Scoundreller wrote:
| Or requiring weight reductions on the aircraft itself
| (fewer pax, lower fuel, less cargo).
| manojlds wrote:
| And the runway is packed away into a hangar rest of the
| times?
| dazc wrote:
| I'm guessing the composition is dictated by local average
| conditions. It rains a lot in the UK and freezing ground
| temperatures are common in the winter too.
|
| I lived in Spain for a while and non-average weather such as a
| day of heavy rainfall can result in disaster movie-style
| scenarios. It's all relative.
| anthk wrote:
| Which part of Spain? On the Atlantic Spain, heavy rainfall
| can just be "Thursday".
| brailsafe wrote:
| I would have guessed local outlier conditions with a bit of
| padding rather than averages, but I suppose those latent
| optimizations get progressively more expensive.
| nonameiguess wrote:
| American highways use a PG rating system for the bitumen in the
| asphalt. You can read about it here:
| https://ftp.dot.state.tx.us/pub/txdot-
| info/cst/tips/faq_pg.p.... Short story is yes, places where it
| is expected to become very hot do use asphalt that doesn't rut
| under higher temperatures. The only exception I know of it
| Death Valley, which technically requires PG 76-10, but uses
| 70-10 just because California deemed it wouldn't be worth it to
| manufacture the extra grade just for one place that doesn't see
| much traffic. So I guess the highways just sometimes melt in
| Death Valley, too.
|
| I do recall being a kid going on road trips through these
| deserts and noticing some of the highways were red and seemed
| to be made of something different. This was before the switch
| to the PG rating system. My dad claimed it had something to do
| with not melting the tire rubber of the vehicles on those
| roads, but I have no clue what his source was and I can't find
| any information about these highways, if they even still exist.
| ibejoeb wrote:
| The runway melts at 40C? Call me skeptical.
| nomel wrote:
| You appear to be correct:
|
| > The RAF didn't specify why it suspended flights, but a
| spokesperson said "the runway has not melted" as early media
| reports indicated.
|
| https://www.cnbc.com/2022/07/18/london-flights-suspended-aft...
| dragonwriter wrote:
| > The runway melts at 40C?
|
| No, the runway melts at a much higher temperature, but as it
| turns out pavement gets much hotter than air temperature on hot
| days; various sites I can find siting a very rough guide as
| 35degC air temperature to 65degC pavement temperature.
| [deleted]
| woodruffw wrote:
| Melted presumably doesn't mean "liquified," it means "the heat
| was sufficient to push the integrity of the runway beyond its
| safe operating parameters."
|
| And it probably wasn't just 40C; it was probably much hotter,
| since it's black tarmac.
| masklinn wrote:
| It's quite believable that the tarmac wouldn't have been
| specced for 40C in England. Especially when the airport opened
| in 1938.
| alias_neo wrote:
| "Tarmac", the stuff we coat roads on here gets very soft in the
| summer.
|
| When I was a child (90s), my dad lost a finger when we were
| replacing the alloys on his VW Corrado and the jack sank into
| the tarmac and collapsed dropping the car, he pulled his arm
| out just quick enough to _only_ lose a finger.
|
| I'll never forget how dismissive my mum was when I said "mum,
| come quick, dad's cut his finger off, it's on the floor".
|
| Fun story aside, the tarmac / road covering we use here do
| "melt" at relatively low temperatures.
| EGreg wrote:
| Did they reattach the finger? Does he still have feeling in
| it and can move it?
| bregma wrote:
| Is it still embedded i the tarmac?
| madengr wrote:
| smcl wrote:
| It's worded that way for shock value:
|
| 1) 40C is the air temperature, the surface temperature of
| something exposed to the sun is much higher
|
| 2) It's not like it's a big hilarious, swirling sea of tarmac.
| Part of the runway will be a bit softer than they deem safe.
|
| The UK heatwave is still extraordinary, but you need to take
| tabloid headlines with a generous pinch of salt.
| SideburnsOfDoom wrote:
| 3 ) there are parts of the world where runways built decades
| ago were built with 40C (expected air temperature) in mind.
|
| Luton, UK is not one of them.
| smcl wrote:
| Also true!
| foibleberry wrote:
| It is more likely the black tarmac used to fill in cracks in
| said runways, and I'm almost certain you've stepped in that on
| a hot day at some point in your life and know that it gets
| soft. No reason to be skeptical based on a hot headline take.
| colechristensen wrote:
| Did it melt or did it buckle because of expansion?
|
| Title says "melt" but the only quoted source in the article says
| "defect".
| lelandfe wrote:
| Yeah, The Sun isn't a _great_ source. Reuters ' title on this
| is "Flights briefly disrupted at UK's Luton airport as heat
| damages runway"
| colordrops wrote:
| My adblocker is blocking the link got some reason.
| dragonwriter wrote:
| Reuters headline yesterday had the "melted" language.
| mgdlbp wrote:
| Huh? The Sun is clearly a great source of radiant heat.
| throwaway0a5e wrote:
| Based on my experience with how airport operations work I
| suspect they noticed a defect on lesser pavement or a service
| vehicle with higher ground pressure than an aircraft left a
| dent somewhere on the runway and they then concluded that they
| should stop bouncing object that weigh tens of thousands of
| pounds off of the runway until it hardens back up lest ruts
| form there.
| capableweb wrote:
| They found a defect, it has not melted. Another source:
|
| > The RAF didn't specify why it suspended flights, but a
| spokesperson said "the runway has not melted" as early media
| reports indicated.
|
| https://www.cnbc.com/2022/07/18/london-flights-suspended-aft...
| rndgermandude wrote:
| Yeah, the "melted" might be incorrect, however the quote from
| the Royal Air Force is about another (military) airport.
| debacle wrote:
| @dang could we have the link updated to a better source?
| nodesocket wrote:
| I don't understand, sure it's hot for London, but not that hot
| (100F). Not even close to as hot as it gets frequently in the
| deserts (Vegas, AZ) and south here in America. Yet, runways are
| melting and the media is absolutely freaking out. It's 100
| degrees, not that big of a deal.
| _dain_ wrote:
| Stuff gets made out of different things in different climates.
| In Arizona it's not a big deal because the engineers expected
| 40 celsius as a regular occurrence and chose material
| compositions to withstand it. In the UK, they didn't, and we're
| seeing the consequences. 40 celsius has never happened in
| recorded British history. The previous record was 37.something.
|
| I imagine Arizona infrastructure would fail pretty rapidly if
| temperatures somehow dropped to -30 celsius, and there would be
| Novosibirskians wondering what the big deal was.
| HarHarVeryFunny wrote:
| It's a big deal because people don't have A/C.
| the_only_law wrote:
| The runway is outside though. I've never heard of runway
| melting in the hottest and most humid parts of the US.
| tehbeard wrote:
| The parts where its been hot and humid since the turn of
| the century? Where they knew back in the 30s and 40s and
| used the appropriate additives in the asphalt/concrete to
| handle those temperature ranges?
|
| We can't change this infrastructure immediately, it was
| built for English summers which used to mean 30 in the air,
| 50-60 ground temp. Now we're pushing 40 air and 80
| ground...
| sophacles wrote:
| Aside - us oldsters from the 1900s need to stop referring
| to ~1900 as "The turn of the century". We're at a point
| where ~2000 will start (maybe is) being referred to as
| "The turn of the century" due to it turning in to the
| current century at that time.
| tehbeard wrote:
| ...I don't like it, but you're right...
| pixl97 wrote:
| You've also never heard of the runways frost heaving in the
| hottest and most humid parts of the US. Things tend to be
| engineered for the climate they experience the vast
| majority of the time.
| tcmart14 wrote:
| Not a civil engineer, but everywhere uses different materials
| spec'ed to withstand the environmental factors that occur
| there. You live in Arizona which uses asphalt that should
| tolerate expected weather conditions in Arizona. It si probably
| a different asphalt than what gets used in Maine and a
| different asphalt that gets used in Florida because all three
| of those place need infrastructure that accounts for different
| weather conditions.
|
| There isn't really a one size fits all answer, each material
| has its pros and cons that works best for different conditions.
|
| Interestingly boring. Idaho has a podcast about their roadway
| system. If you listen to enough episodes, one thing you learn
| is Idaho uses different kind of asphalt in different areas of
| the state. Why is that? Some part of the state have the high
| desert climate and other parts of the state have a more colder
| and mountainous climate.
| Pengtuzi wrote:
| "I can't believe how those southerners can't handle 1 below
| freezing and half an inch of snow, it's not even that cold"...
|
| Because infrastructure is built in a local context, where
| materials, designs et cetera are chosen on what is/was normal.
| I'm genuinely curious: do you really not understand this?
| [deleted]
| montalbano wrote:
| its about temperature difference relative to geographic norms.
| this is the hottest recorded temperature in UK history.
| matthewmacleod wrote:
| It is _literally_ the hottest that the UK has ever been in
| recorded history. It is roughly the same temperature as the
| high in Tucson today. It is very hot.
|
| You can build infrastructure for this heat. The UK does not
| have that. This is why runways are melting and the media is
| freaking out.
| [deleted]
| tailspin2019 wrote:
| Also the media don't generally need much of an excuse to
| freak out.
| badcppdev wrote:
| Sadly there isn't a functioning government in the UK that can
| freak out and do something about it.
| sophacles wrote:
| Let me guess this is you last year:
|
| I don't understand, sure it's cold for Texas, but not that cold
| (0F). Not even as close to as cold it gets frequently in the
| tundra (Winnipeg, Saskatoon) and north there in Canada. Yet
| pipes are freezing and the media is absolutely freaking out.
| It's 0 degrees, not that big a deal.
|
| Point being, a place has all it's infrastructure designed for
| the climate it's in, not a different place's climate.
| ibejoeb wrote:
| mirekrusin wrote:
| Spray it with water?
| lm28469 wrote:
| You'd need to design a system and make it pass all sort of
| tests and specifications.
|
| It's not as easy as bringing two firetrucks and spraying for 10
| minutes. When mistakes end in potential dead people they don't
| DIY solutions
| mcguire wrote:
| Back of the envelope calculation:
|
| Yuma International (discussed above) has 540,000m^2 of runways.
| Assume a depth of 0.1m of cooling, that is 54,000m^3. The
| density of asphalt is 2322kg/m^3, so we have 3 _10^9kg. The
| specific heat of asphalt is 900 J /kg_K, so that'd be 3 _10^12J
| to get rid of 1 K degree. The specific heat of water is 4184J
| /kg_C. If I assume the water goes from nearly freezing to
| nearly boiling and have my algebra right, that's about
| 6,000,000kg of water or about 6000m^3 of water, all to lower
| the asphalt by 1 degree. That's about 2.5 standard bulk units
| of water (Olympic swimming pools).
|
| By comparison, 2.5cm of rain on the same runway area is about
| 13,500m^3 (?) of water.
|
| I think it's doable. Anybody got some spare garden hoses? :-)
| mcguire wrote:
| Formatting. Sigh.
| dragonwriter wrote:
| flooding the runway would temporarily deal with the heat but
| also render it unusable for a different reason.
| skykooler wrote:
| Why? Airplanes are able to land in the rain.
| pixl97 wrote:
| Cools the runway but can make the local atmosphere more
| dangerous for humans.
| oittaa wrote:
| ITT: Americans not understanding that London is at the same
| latitude as Calgary, and Houston is located around Kuwait's.
| dang wrote:
| " _Please don 't sneer, including at the rest of the
| community._" It's reliably a marker of bad comments and worse
| threads.
|
| Also, please don't post nationalistic flamebait--it leads to
| nationalistic flamewars, which are the last thing we need here.
|
| https://news.ycombinator.com/newsguidelines.html
|
| Edit: it looks like you've been posting quite a few flamewar
| comments, unfortunately. Can you please not do that? It's not
| what this site is for, and it destroys what it is for, so we
| end up having to ban such accounts.
| retard111 wrote:
| photochemsyn wrote:
| They could have planned for upgrading infrastructure to cope with
| expected warming trends beginning 35 years ago or so, but that
| would have entailed admitting that the science of atmospheric
| CO2's effect on climate had essentially been settled since 1980.
|
| Send BP and Shell the bill for the infrastructure upgrade, since
| they spent so much time and effort on science denialism in the
| 1980s and 1990s and 2000s.
| RGamma wrote:
| That's too expensive. The sheikhs would no longer be able to
| build their ski resorts in the desert.
| epistasis wrote:
| Sadly to this day there are people who have been politicized
| into disbelieving the science, which has been very clear for a
| long time.
|
| I fear for our ability to deal with the problems of humanity
| when so much of our politics is easily fooled people fighting
| ideological wars for the benefit of others.
| treeman79 wrote:
| Standard politician.
|
| "Vote for me or the world ends"
|
| "Your a climate denier if you point out that I just use
| climate to in-rich myself"
| epistasis wrote:
| What politician is enriching themselves with climate
| change? Especially compared to all the politicians that
| enrich themselves via denial?
| treeman79 wrote:
| Al Gore, John Kerry.
| epistasis wrote:
| And these politicians putting their money where their
| mouth is means that you disbelieve the science?
|
| When people like Joe Manchin refuse to take climate
| action, due to his investments in fossil fuels, doesn't
| that make you think we should take climate action?
|
| Why does this sort of reasoning go only one way?
| timeon wrote:
| Interesting how you want to turn the argument around while
| the lawns in UK started burning. What for? Did he itched
| your political indoctrination? It is sad that people needs
| to choose sides in these things. Wish you had more
| possibilities to choose from.
| pessimizer wrote:
| There are also some that think that only God can control the
| weather, so if the world is warming that is His will; and
| that the end of the world is imminent, and will be the
| greatest moment in the history of the universe for the
| faithful.
|
| I'd bet that probably 20% of the voter base believes exactly
| that, and that 10% think that not believing that should be
| grounds for deportation or imprisonment.
| [deleted]
| astockwell wrote:
| Don't Look Up ;)
| 88840-8855 wrote:
| I fully agree. In addition charge back all dividends paid as
| global warming was long a scientific fact. Profits always must
| come with responsibilities. Time that people who profited are
| paying their bills.
| [deleted]
| hristov wrote:
| The great irony is that BP and Shell did plan for global
| warming and did upgrade their infrastructure accordingly. Even
| back in the 80s, they build their ocean drilling rigs to be
| high above the water knowing full well that they were causing
| the icebergs to melt and the water level to rise. They just
| kind of forgot to let us rubes know about it.
| borissk wrote:
| There were plenty of scientists letting the public know about
| the global warming in the 80s. The public didn't want to know
| about it.
| einpoklum wrote:
| Don't blame "the public". This wasn't some conscious
| informed choice by millions of people. The public sucks the
| glass teat of mass media, and the interests controlling it
| did not want to present global warming as a problem.
|
| In fact, this state of affairs has not even changed that
| significantly.
| the_only_law wrote:
| > The public sucks the glass teat of mass media
|
| Ok I'll blame them for that then.
| chappi42 wrote:
| Of course the public was (and is!!) the culprit. Only the
| individual "footprint" is so small that almost nobody
| does something.
|
| Real structural changes are hard to enforce. There is
| always something more pressing, just look e.g. at the 100
| billion Germany spends on war (how many trees that would
| give?). As a politician it would be the end of the career
| if you tried to enforce something really drastic (and so
| nobody does it, incl. "the greens").
| borissk wrote:
| All right, but blaming the mass media is not much more
| helpful. What do suggest - nationalize it all?
| eternauta3k wrote:
| As you were writing this post, did you have a source for
| this, or was this hearsay? Not asking you to look for a
| source now, just curious about the quality of information in
| HN.
| hristov wrote:
| https://graphics.latimes.com/oil-operations/
| replyOnce wrote:
| There is this article from ArsTechnica talking about a
| lawsuit from the city of New York against chevron which
| describes the issue described by the OP
| https://arstechnica.com/tech-policy/2018/07/judge-
| dismisses-...
|
| The direct quote from the complaint (found here on page 5:
| https://cdn.arstechnica.net/wp-
| content/uploads/2018/07/show_...) would be: _Meanwhile,
| beginning in the mid-1980s, Exxon and other major oil and
| gas companies, including Mobil and Shell, took actions to
| protect their own business assets from the impacts of
| climate change, including raising the decks of offshore
| platforms, protecting pipelines from coastal erosion, and
| designing helipads, pipelines, and roads in the warming
| Arctic)_
| LQDH wrote:
| I don't know about BP, but this internal memo from 1988 is
| what people are referring to when they say shell knew about
| climate change in the 80s:
| https://biotech.law.lsu.edu/blog/Shell_Climate_1988.pdf
| afry1 wrote:
| Source here: https://graphics.latimes.com/oil-operations/
|
| The investigative research that brought this up was a big
| development in proving that they knew on an institutional
| level that the science was real.
| heliodor wrote:
| Global warming is caused by burning fuel, not by extracting
| it. To say Shell and BP caused the icebergs to melt is
| ridiculous.
| [deleted]
| pessimizer wrote:
| Gunshot wounds are caused by the impact of the bullet, not
| the pulling of the trigger. To say I killed that guy is
| ridiculous.
|
| edit: at least someone who sells bullets or guns has the
| excuse that they can be used for sports or entertainment.
| If you pull oil out of the ground, it's meant to be burned,
| made into plastic, or put outside to roast in the sun.
| Taylor_OD wrote:
| They suppressed the information that global warming was
| happening.
| heliodor wrote:
| Yes they did. But the original statement is still
| ridiculous.
| jdgoesmarching wrote:
| Are you seriously arguing that two of the largest oil and
| gas companies in the world have no hand in contributing
| to global warming? Over a 27 year period, they are
| collectively responsible for producing 3% of the world's
| greenhouse gas emissions:
|
| https://www.theguardian.com/sustainable-
| business/2017/jul/10...
|
| Glad to know people will still be pedantically splitting
| hairs as the world literally burns.
| crote wrote:
| Are you sure about the oil rigs? The thing with ocean is that
| there tend to be _waves_. They are designed to survive once-
| in-1.000-year storms or worse, especially since the Draupner
| E platform got hit by a huge rogue wave in 1995.
|
| Sea level rise is measured in millimeters per year. When a
| platform is already 20-30 meters above the sea, the handful
| of centimeters of sea level rise over its lifespan is
| completely insignificant.
| pastor_bob wrote:
| Much of the London tube doesn't have AC. Talk about lack of
| planning. Pretty sure all lines of the NYC Subway had ac 25+
| years ago and they're notorious for drawing out project
| timelines.
| iainmerrick wrote:
| To be fair, that's been a work in progress for years, and
| some lines do have AC. It's not like they haven't been
| planning for it at all.
|
| IIRC a big difficulty is that the tunnels are extremely
| narrow, so it's just difficult to get any extra equipment in
| there. (I wouldn't have thought that's insurmountable,
| though, so there's probably more to it than that.)
| drcongo wrote:
| Great article on the why here:
| https://www.ianvisits.co.uk/articles/cooling-the-tube-
| engine...
| pmyteh wrote:
| Space in the deep tube tunnels is _really_ tight[0] (making
| it tricky to fit on-train air con radiators) and there 's
| insufficient air circulation in the to clear the extra heat
| emissions in any case. They're working on both, but (unlike
| the shallower cut-and-cover lines and the NY Subway, both of
| which have saner tunnel sizes) it's decidedly non-trivial.
|
| [0]: https://commons.m.wikimedia.org/wiki/File:Why_London_Und
| ergr...
| ClumsyPilot wrote:
| but many trains without lack if space, like DLR, are also
| without AC
| pmyteh wrote:
| Yeah, that's true. Expect that will change with the next
| set of new trains, as with the newish S Stock on the
| subsurface lines. Not all mainline trains have AC either,
| though I think it's been nearly universal on new trains
| from the 90s onwards.
| borissk wrote:
| The tube is for the dirty working class, AC is for the elite.
| A few weak people dying in London is no big deal - that's how
| life in London always worked.
| secondcoming wrote:
| Everyone in London uses the Tube. What are you on about?
| borissk wrote:
| What are YOU on about? Have you seen the queen, BoJo or
| any really rich person on the tube?
| secondcoming wrote:
| I've seen several wealthy celebrities, yes.
| BurningFrog wrote:
| NYC is also a _much_ warmer summer city than London.
| yardstick wrote:
| Thankfully the Elizabeth line, opened this year, has AC. Both
| in trains and stations (at least the new build ones).
|
| Small steps...
| lelandfe wrote:
| Little consolation when you're waiting 15 minutes for the R
| train on the sweltering platform, ugh.
|
| But yeah - sadly London's system used to be pretty cool, but
| the clay interior has acted like a battery, slowly absorbing
| the heat, and it simply can't absorb any more. It's a massive
| engineering problem (and oversight).
| Symbiote wrote:
| The lines without AC were constructed (mostly) in the 19th
| century. It's not possible to fit AC.
|
| Alternative ways to cool the trains have been under
| investigation for decades, but there isn't an obvious
| solution.
| treeman79 wrote:
| They didn't need AC in 19h century. The ground itself was
| cool and kept people comfortable.
|
| 200 years of constant usage has heated up the surrounding
| bedrock.
| secondcoming wrote:
| There was a competition to see if anyone could solve the
| problem
|
| http://news.bbc.co.uk/1/hi/magazine/3069037.stm
| [deleted]
| Milner08 wrote:
| Its much harder on the tube, as where do you dump the hot
| air? Back into the tunnel? London's clay has basically baked
| around the tube and is a really good insulator. Its not a
| particularly easy problem to solve.
| munificent wrote:
| You vent it to the surface, at least that's what NYC does.
| treeman79 wrote:
| 1955 opening day of Disneyland.
|
| In temperatures that reached 100 degrees, the fresh asphalt on
| Main Street, USA melted into a sticky tar that ensnared the
| high heels of some women
|
| https://www.history.com/.amp/news/disneylands-disastrous-ope...
| philliphaydon wrote:
| That's only 37 degrees in normal people temp.
| Closi wrote:
| The main reason for this was that they just laid the asphalt
| too late and it didn't set in time.
|
| Disneyland was built with remarkable pace, with some of the
| original rides being closer to 'industrial machinery with
| chairs attached' than you might imagine!
| DrBazza wrote:
| If by infrastructure, you mean trains, then the UK, like every
| other country uses rails appropriate to the average
| temperature.
|
| "Network Rail said that its rails have a "stress-free"
| temperature of 27 degrees."
|
| https://www.bbc.co.uk/news/business-62182880
| bloqs wrote:
| Why would all countries not just use rails that can tolerate
| all possible temperatures.
| HankB99 wrote:
| I'm pretty sure it comes down to cost. Steel rail has to
| meet certain wear and strength requirements as well as be
| reasonably inexpensive to manufacture. And there is not
| likely an alloy that will accomplish that and not expand in
| the heat.
|
| In the US, the typical construction method is welded rail.
| AFAIK there is no allowance for expansion, at least on
| straight sections. Perhaps curved sections can move a bit
| to allow for expansion but move too much and the train goes
| off the tracks.
| [deleted]
| yojo wrote:
| Not sure why you're getting downvoted. This seems like an
| earnest question.
| OJFord wrote:
| 'All possible'? What are _all possible_ temperatures? I
| think you 've answered your own question, if you think
| about it: a line has to be drawn somewhere, you have to do
| some sort of statistical analysis, chance of circumstances
| occuring which this would not cope with <x%, yeah ok good
| enough, that sort of thing. That's engineering.
| smileysteve wrote:
| That's not the way metal works.
| Milner08 wrote:
| Because that's not possible without a lot of expense. Metal
| expands thats just basic physics. Its hard to stop that.
| bonzini wrote:
| And it also contracts.
| surement wrote:
| > Send BP and Shell the bill for the infrastructure upgrade
|
| Should they also get credits for all the progress oil has
| allowed us to make?
| Quenty wrote:
| Have they not already been financially compensated for this?
| surement wrote:
| No, they extract and sell oil and they happen to do it at a
| profit. This is not the same as being compensated or billed
| for things that resulted from the use of that oil.
| Jenk wrote:
| That's called _money_.
| psi75 wrote:
| vegancap wrote:
| Yeah we're not really equipped for this...
| bergenty wrote:
| I don't understand this. Do they use different asphalt up
| there?
| TT-392 wrote:
| I wouldn't be surprised, there are a lot of different asphalt
| mixes out there for different scenario. Idk specifically
| about temperature, but would't be surprised.
| edm0nd wrote:
| I had a local HVAC guy once tell me that the next Elon Musk type
| is going to be whomever owns the largest HVAC company in the UK
| and Europe.
| bergenty wrote:
| We already have mature HVAC companies. They're just going to
| expand their operations in Europe.
| mikewarot wrote:
| Why would concrete melt, ever? Someone used the wrong words, or
| didn't understand what they were told.
|
| [Edit] Ok, so they made poor choices in runway materials. O'Hare
| and other airports near me are all steel reinforced concrete.
| nathanaldensr wrote:
| Not only that, but forget concrete: think asphalt. Having lived
| in Texas with countless 100+ F days, I can confidently say the
| asphalt never melted.
|
| What are they paving runways with in Luton, anyway?
| capableweb wrote:
| > "I can't believe how those southerners can't handle 1 below
| freezing and half an inch of snow, it's not even that
| cold"...
|
| > Because infrastructure is built in a local context, where
| materials, designs et cetera are chosen on what is/was
| normal. I'm genuinely curious: do you really not understand
| this?
|
| https://news.ycombinator.com/item?id=32154999
|
| Seems many people in this thread have trouble understanding
| that most of the infrastructure we build is built for the
| people living there under the conditions they normally
| experience, not for "freak" outliers like this.
|
| Similar to how if there is snow in southern Europe, most
| infrastructure shuts down while in Russia they run trains
| through snowstorms. But if it gets tiny bit too hot in
| Siberia, the trains shut down while in southern Europe they
| survive no matter how hot it gets.
| kennend3 wrote:
| So many crazy posts like yours...
|
| As others have said, why did Texas have so many problems when
| it got cold?
|
| Taking our infra, designed for your temps and stating "others
| should have this too" doesn't make sense.
|
| I live just outside Toronto (Ontario). When you were
| struggling with a brief cold snap which cost 246 lives
| because it was -19C, large and heavily populated parts of
| Canada faced -40C and no one died?
|
| "Texas was not winterized, leaving it vulnerable to extended
| periods of cold weather, leading to widespread power outages"
|
| why wasn't it winterized?
|
| Because statistics show it was a controlled gamble NOT do to
| this. UK airport is the same deal.
|
| They could use different (and more expensive) materials, but
| they gambled it wouldn't be needed, much as why Texas didn't
| winterize the equipment.
| pixl97 wrote:
| Remember that time in Texas all our infrastructure shutdown
| because it got cold here?
|
| Next, you seem to be completely clueless on aggregate mixes,
| your mix will be a balance of rock and tar meant to survive a
| temperature range. Texas mixes will be more aggregate. The
| problem is this make it less flexible in cold weather and it
| would degrade far faster. So great you'd design a runway to
| survive Texas heat that occurs once every few decades versus
| the cold winters that happen every year.
| badcppdev wrote:
| How is the infrastructure in Texas generally? Roads? Bridges?
| Power grid?
| dheiwnsjsnsnek wrote:
| > Why would concrete melt, ever?
|
| The components of concrete melt, and they melt not long after
| steel does. You'd have entirely melted concrete before 2,000
| deg C, depending on what's in it. When rock melts, it becomes a
| material quite familiar to you. Cement melts sooner, and those
| are the two main components.
|
| We're not talking about that, though, as the issue at this
| airport is squishiness of tarmac.
| chrisseaton wrote:
| > Why would concrete melt, ever?
|
| The runway is made from asphalt concrete, in which the bitumen
| binder starts to melt in the temperatures being experienced.
|
| > Someone used the wrong words, or didn't understand what they
| were told.
|
| That someone is you.
| neilalexander wrote:
| It's tarmac, not concrete.
| jonplackett wrote:
| More likely, someone decided to amp up the drama trying to get
| more clicks.
|
| The media coverage of the heatwave has veered between upbeat
| excitement and scaremongering - but never about the real issue
| of climate change. Just about a runway with a bit of a chip in
| it
| nomel wrote:
| This does appear to be the case:
|
| > The RAF didn't specify why it suspended flights, but a
| spokesperson said "the runway has not melted" as early media
| reports indicated.
|
| https://www.cnbc.com/2022/07/18/london-flights-suspended-
| aft...
| AHappyCamper wrote:
| Essential service melts at 40degC..... well, that wasn't designed
| very well, was it?
| psi75 wrote:
| When these designs were made, 40 degC in the UK was a once-
| in-5,000-years event. Now, it seems to be about 1 in 30 years
| (we don't have enough data to be sure).
|
| Also, the problem usually isn't the 40-degree air temperature
| itself, because that's usually in the operating range--it's the
| rails and machinery and confined spaces hitting 60+ that fucks
| everything up.
|
| New York considered shutting down its subways in July 2011 when
| it was "only" 40.5. Why? Because the underground stations were
| hitting 50, which (esp. in New York humidity) is dangerous for
| the most heat-sensitive people.
| AHappyCamper wrote:
| I'm sorry, but that's a whackadoodle approach to engineering.
| 40C is well within the range of expected temperatures, and
| the men who designed it failed epically. There have been
| heatwaves in the UK since 1911 where the temp approaches 40C.
|
| https://www.theguardian.com/uk-news/from-the-archive-
| blog/20...
| jfax wrote:
| All of those temperatures are multiple degrees below 40.
| retrac98 wrote:
| I doubt it's a once every few decades event anymore. It got
| to 38 in several places in the country a few years ago. It
| seems to get up to the mid 30s every year now.
| dreen wrote:
| It was designed for conditions known to exist in the area. Then
| conditions changed due to climate change.
| crote wrote:
| It's one of London's six airports, primarily used for discount
| holiday flights. Hardly safety-critical.
|
| Besides, this is _literally_ the first time _ever_ it has
| reached temperatures this high - and it has been open for 84
| years. I bet they also "failed to design" for hurricanes,
| cataclysmic floods, and volcanoes!
| jacquesm wrote:
| Two out of those three are a real possibility though.
| secretsatan wrote:
| Now they are
| AHappyCamper wrote:
| That still sounds like really, really, really bad design. 40C
| is not a hurricane, flood, or volcano. It's a mildly hot day.
| Engineering fail.
| barnabee wrote:
| As I understand you are engineering for a range of
| temperatures with problems to be found outside either end
| of the range (though I imagine it's also possible to
| engineer for wider or narrower ranges to some extent, with
| appropriate cost implications).
|
| Coping with higher maximum temperatures means more cracking
| and damage at very low temperatures, so it is not
| necessarily a case of just building in more buffer at the
| top end but a trade off between the cost and frequency of
| events like this and the cost of dealing with the effects
| of winter.
|
| Given that this had literally never happened before and the
| frequency of similarly hot events was also lower in the
| past, it's perhaps unsurprising that the trade-off landed
| where it did, even if it may well be in for a rethink now.
| pixl97 wrote:
| Wait till you learn about the Texas electric grid.
| odiroot wrote:
| Luton is not that important. If Heathrow or Gatwick melted,
| there'd be riots.
| andylynch wrote:
| The problem is these temperatures are quite a bit higher than
| ever previously recorded, and go beyond the reasonable
| scenarios for which they were built. I'm sure sure newer UK
| infra is designed for higher temperatures but this is new
| territory and unfortunately probably just a taste of what's
| coming.
|
| Worth also adding this wasn't as bad as it sounds- only a small
| patch was faulty and fixed within a few hours. For bigger
| problems see the various wildfires and also widespread
| breakdowns in chilled food storages. I also hate to think how
| barn animals are faring.
| nottorp wrote:
| > The problem is these temperatures are quite a bit higher
| than ever previously recorded, and go beyond the reasonable
| scenarios for which they were built.
|
| Exactly. I remember talk in the press about the default
| asphalt composition for the roads where I am (Romania) being
| changed to handle higher temperatures like 15 years ago.
| We're a lot more to the south and got warmer faster than the
| UK.
|
| It's just the UK's turn now.
| buildsjets wrote:
| The automated weather broadcast at Yuma airport in Arizona
| reports the runway temperature. Yuma is a joint civilian/military
| use airport and some fast jets have a surface temperature limit
| for their tires. I was there doing some flight test work once and
| it was reporting 160F, it wasn't even a super hot day.
| badcppdev wrote:
| Latitude of Yuma, US: 32.6deg N
|
| Latitude of London, UK: 51.5deg N
|
| To be clear they are talking about the air temperature rather
| than runway temperature and I've added the latitude so you can
| understand why it's a big deal that London has hit 40 degrees.
| fdsafdsfdsa wrote:
| While we're picking random data points - Malillia (Sweden),
| at 57deg N, set a record temperature of 38degC in 1947.
| MobiusHorizons wrote:
| They are not random. Those are the two locations being
| discussed in the thread you replied to :)
| secretsatan wrote:
| Oh wow, that's really interesting, was it just a freak
| event or part of a trend?
| formerkrogemp wrote:
| Trend. Check out the latest IPCC report for more info.
| secretsatan wrote:
| -> Hard to Say
|
| That's weird, some cursory searches show a definite
| upward trend for quite some time, i do find these weird
| sites where they consistently pick outliers in a
| dishonest manner. It really wouldn't be worth engaging
| with them though
| fdsafdsfdsa wrote:
| fdsafdsfdsa wrote:
| HarHarVeryFunny wrote:
| I've been at Phoenix airport on a hot, but not crazy hot, day
| where the parking lot asphalt was tacky and stuck to your
| shoes.
| zerkten wrote:
| Have Yuma temperatures actually changed that much? A quick
| check suggests that the level of change is much smaller than
| that in the UK. Climate change has increased the extremes in
| the UK quite significantly in the last 40 years. It's a case
| that the changes in extremes are not accounted for in UK
| planning whereas Yuma is known to be consistently very hot.
| yetanotherloser wrote:
| Also I'm sorry but the UK bloody loves a bit of weather
| melodrama. Climate change is a big problem but the specific
| effect of it on the UK in particular has honestly not been
| very bad at all yet. Tarmac has been melting in the heat here
| longer than I've been alive, which makes me suspect we use
| weak, crappy British tarmac. This was a little bit hotter
| than previous heatwaves, which is bad, but felt about the
| same and has also been really short - not sure what to make
| of that. However we scarcely get a weekend here without some
| "most (x) ever in (y)" fuss and haven't in 40 years which is
| really getting quite tiresome and making it harder to respect
| the real problems. I'll worry about it when I'm done drinking
| gin in the rain.
| throwaway821909 wrote:
| >most (x) ever in (y)
|
| The hottest temperature ever recorded here isn't some niche
| thing like most rainy April for 5 years. Also maybe the
| fact that there's constantly new unusual weather should
| tell us something.
| dkarl wrote:
| Not just the UK. It's been over 100o a lot of days here in
| Texas, and people from other places in the U.S. keep asking
| me how it feels, like it's a brand new and shocking
| experience. But from a perceptual perspective, it's normal.
| My perceiving brain doesn't do sophisticated statistics. It
| isn't a scientist. My brain's reaction to 100o+ weather is,
| well, this sucks but it's a familiar, age-old kind of suck.
| I spent time outdoors in 100+o weather every summer growing
| up, so I just don't make a gut connection between a string
| of hot days and my sense of fear and urgency about global
| warming.
|
| > really getting quite tiresome and making it harder to
| respect the real problems
|
| I agree that it trivializes and undermines the real problem
| of global warming. People have this false implicit
| assumption that if global warming is real it must be
| possible to immediately perceive it, and instead of
| challenging that, we keep trying to inject drama and danger
| into familiar experiences, and it just rings false. On a
| subconscious level, I suspect we all know it's silly. Also,
| what happens if it's not this hot next year? After spending
| 2022 essentially telling people that they can directly
| perceive global climate trends by walking outside, what
| will they think if the summer of 2023 is relatively cool?
|
| I'm probably wrong, I'm not an expert in public opinion, it
| just feels false.
| psi75 wrote:
| I buy the 71 C ground temperature; ground temperatures can be
| 25-35 C hotter than the ambient air temperature, which is
| what gets recorded. This is also why rails buckle more than
| you'd expect: on a 40 C day, you're likely to see the rails
| heating up to 60-65 (as in, if you touch them, your finger
| will burn).
| nomel wrote:
| > ground temperatures can be 25-35 C hotter than the
| ambient air temperature, which is what gets recorded
|
| Ground temperatures are almost entirely responsible for the
| majority of the thermal energy/temperature put into the
| air, down at the surface.
| Consultant32452 wrote:
| The Phoenix airport has to close down during peak temperatures
| on summer days because it exceeds the maximum operating
| temperature of the airplanes. Pretty cool.
| collegeburner wrote:
| yeah lol not surprised. im in texas, not even as hot as
| arizona, and friends motorcycle kickstands have lowkey melted
| into ashpalt a few times.
| derefr wrote:
| Any reason that airports in super-hot places like that, don't
| run heat-transfer coils under their runways, to cool them down
| with a heat pump like a skating rink does? Runways aren't an
| order-of-magnitude larger in surface area than skating rinks,
| so it's not cost. And they wouldn't even need to turn on the
| heat pump for 3/4ths of the year. Do we just not know how to
| create heat-transfer coils that wouldn't break from the stress
| of planes landing "on" them?
| kevin_thibedeau wrote:
| They either use concrete or have different asphalt blends
| that handle higher temperatures.
| morsch wrote:
| I imagine skating rinks in temperate/hot places are indoors
| and well insulated. Your solution would work well for an
| indoor runway.
| bigbillheck wrote:
| > Runways aren't an order-of-magnitude larger in surface area
| than skating rinks,
|
| International hockey rinks are 30m by 60m. My local airport,
| which isn't that big as far as these things go, has two
| runways each of size 45m by 2200m. That's 55x larger per
| runway.
| mcguire wrote:
| Hm. An Olympic ice rink is 30mx60m, or 1800m^2. The "largest
| ice arena complex in the world"
| (https://en.wikipedia.org/wiki/Schwan_Super_Rink) is
| 28,000m^2 but has 8 Olympic ice rink, sort of.
|
| Yuma International/MCAS has roughly 540,000m^2 of runway
| (plus taxiways).
| badcppdev wrote:
| Your comment fascinates me. A normal ice hockey rink is 1,800
| square meters. The biggest indoor ice rink in the US is the
| Schwan Super Rink = 28,000 sqm which consists of 8 separate
| rinks.
|
| Yuma's 4 runways total 543,000 sqm. At midday those runways
| are absorbing 543MW of energy from the Sun. So that might
| require 100-200KW of electricity to run the heat pumps. And
| then you still need somewhere to dump the heat.
|
| In short, I think the reason they don't cool runways is due
| to the cost.
| johnwalkr wrote:
| There's a ton of comments on HN like this. A quick
| brainstormed "why don't they just.." as if cooling a
| runway, building a subway, conducting space travel or doing
| anything else bound by physics is as trivial just because
| it is conceptually simple. Might as well ask why you can't
| ski in your backyard in London because after all it is
| trivial to add some pipes to your refrigerator.
|
| Also I don't know of any skating rinks that operate
| outdoors in summer, or to use a more favourable example,
| something like lowering a surface temperature from 20C to
| -5C (an ice rink, indoors) vs lowering a surface
| temperature from 80C to 55C (an assumption for a runway,
| outdoors). Even Dubai, a major transport hub, much hotter
| than UK even this week, with cheapish energy costs, little
| public debate uses other mitigations such as runway
| materials and scheduling many takeoffs for 2-5AM (there are
| many costs due to high temperature besides runway
| degradation).
| yetanotherloser wrote:
| Then we wonder why when it's hot, it's really bloody hot at
| airports. Is that sum really right? that an airportsworth
| of tarmac is like a whole power station pumping its entire
| output into ground heat? because it looks right to me and
| it seems like the easy, sensible option is just to rip up
| the airport...
| Scoundreller wrote:
| I'd just douse them with water. It's not like UK airports and
| pilots can't handle wet runway landings.
| konschubert wrote:
| They probably use a different ~~tarmac~~ material composition
| for the runway.
| kube-system wrote:
| Luton is all asphalt. The long runway at Yuma is concrete and
| the shorter ones are part asphalt part concrete. And they
| likely chose the asphalt formulation appropriately given that
| they're in the middle of a desert.
| squarefoot wrote:
| I would expect their asphalt being a lot harder and more
| heat resistant than the one that let my motorcycle fall
| multiple times in the past years because it melt during
| summer heat. I clearly wouldn't expect airplanes wheels to
| "sink" into asphalt like my bike stand, but they need a
| strong grip when braking during landings which I doubt a
| much softer surface would offer. Not an expert though, just
| speculating.
| jacquesm wrote:
| A softer surface would give _more_ grip, not less. In
| fact it would give so much grip that it starts to adhere
| to the tires.
| squarefoot wrote:
| You're right of course, what I wondered was if the
| asphalt could become so soft that it loses consistency;
| some of it surely adheres to the tires, but what if it
| would do that by detaching from the runway? However, I'm
| certainly biased for having seen asphalt so softened by
| summer heat that I could leave my tracks just by walking
| on it.
| Scoundreller wrote:
| I'd assume rainy UK would have softer runway surfaces for
| wet-weather performance.
|
| Unlike car tires where people may switch them between
| climates/seasons, aircraft tires need to be fairly
| universal.
| onlyrealcuzzo wrote:
| In case anyone is curious why tarmac gets so hot:
|
| > The rate at which an object can reflect solar radiation is
| called its albedo [source: Budikova]. The bigger the albedo
| something has, the better it reflects radiation. Traditional
| asphalt has a low albedo, which means it reflects radiation
| poorly and instead absorbs it.
|
| Asphalt has an albedo of ~0.05 - which means it absorbs ~95% of
| solar radiation. Tarmac is ~0.1 - which means ~90%.
| lamontcg wrote:
| Anyone out there trying to figure out white tarmac/asphalt?
| [deleted]
| tehbeard wrote:
| Probably not the wisest idea to have a highly reflective
| material as the landing surface for planes humans are
| flying.
| nomel wrote:
| Yeah, but it might be useful for the roughly 4 million
| miles of road in the US.
| tehbeard wrote:
| Actually saw it mentioned that albedo isn't directly
| connected to colour (and in particular since it's thermal
| radiation it'll be towards the IR side of the spectrum)
| there might be alternatives to "nuke flash white" paint
| colour.
| nomel wrote:
| It's only directly related in the visible spectrum, which
| is a slice that contains around 50% of the spectrum that
| the sun throws out, by energy. I would imagine the actual
| color would be something near orange.
| yellowapple wrote:
| > I would imagine the actual color would be something
| near orange.
|
| Which happens to be close to the color of adobe. I'm yet
| again starting to think that native peoples were onto
| something.
| anamexis wrote:
| You can make runways out of concrete.
| jedberg wrote:
| But then you have to close the runway for extended
| periods for repair. The beauty of tarmac is that it cures
| quickly.
| selectodude wrote:
| Most runways, at least at busier airports, are already
| concrete.
| thehappypm wrote:
| Probably absorbing heat quickly is good for cold climates,
| to keep warm on cold days. It might prevent ice buildup on
| days near freezing.
| drhodes wrote:
| I didn't know there was a difference between the two!
|
| > Asphalt is a mixture of aggregates and bitumen that needs
| up to two days before it completely cures. Whereas, Tarmac is
| a combination of crushed stone and tar that cures quickly.
|
| https://tarmacdriveways.ie/key-differences-tarmac-vs-
| asphalt...
| JoeAltmaier wrote:
| Interesting! I often wondered while sitting on a runway, if
| tarmac was so good, why don't we get any? It's just at
| airports!
| selectodude wrote:
| Strangely, you don't sit on Tarmac, even on a runway.
| Airport ramps, aprons and most busier runways are paved
| with high strength concrete.
| senkora wrote:
| From your link I learned that tarmac is short for
| tarmacadam, named after John Macadam, who is also the name-
| origin for macadamia nuts.
|
| https://en.m.wikipedia.org/wiki/John_Macadam
| the_jeremy wrote:
| That is incorrect. John McAdam[0] has the name for
| tarmac, while John Macadam[1] has the name for macadamia
| nuts.
|
| 0: https://en.wikipedia.org/wiki/John_Loudon_McAdam
|
| 1: https://en.m.wikipedia.org/wiki/John_Macadam
| andy_ppp wrote:
| How much would putting mirrors on the earth affect climate
| change? How large a mirror would you need to make a
| difference?
| elil17 wrote:
| Practically, high albedo materials (essentially they
| reflect a lot of light but aren't necessarily mirrors
| because they do scatter the direction of that light) can
| reduce building's HVAC energy consumption. They can also
| effect city level microclimate (mitigating the heat island
| effect).
|
| It takes a lot of high albedo area to effect the overall
| climate. For example, melting ice caps do decrease the
| albedo of parts of the Earth, accelerating climate change.
| Large scale increases to Earth's albedo in the form of
| space mirrors were seriously considered as options for
| global warming mitigation as late as the Obama
| administration. However, the risks of unintended
| modifications to the environment (e.g. crop failures,
| unpredictable weather) are generally considered too great.
| At present, space mirrors, with an estimated lifetime cost
| of $5 trillion for 50 years of cooling, could be a decent
| "last resort" option compared to the possibility of
| spending hundreds of trillions upfront to permanently solve
| the problem with carbon capture (although cost estimates
| vary widely based on the amount of CO2 that needs to be
| captured).
|
| Other options include stratospheric aerosol injection (http
| s://en.wikipedia.org/wiki/Stratospheric_aerosol_injectio...
| ) which could minimize the effects of climate change for as
| little as $55 billion/year, and marine cloud brightening
| (https://en.wikipedia.org/wiki/Marine_cloud_brightening),
| which could cost as little as $5 billion/year. Possible
| side effects might include ozone depletion and acid rain
| for aerosols. Marine cloud brightening could cause weather
| changes.
|
| So yes, you could manipulate albedo but it will always come
| with side effects and costs.
| aeroman wrote:
| Some of the side effects are common to all kinds of solar
| radiation management (SRM) - geoengineering that makes
| the Earth more reflective in some way or another.
|
| Greenhouse gases absorb infrared radiation emitted by the
| Earth and heat the atmosphere as well as the surface. SRM
| geoengineering just changes how much energy the Earth
| absorbs from the sun (which has the strongest effect at
| the surface).
|
| If GHGs increase, but you use SRM to keep the surface
| temperature fixed, you still end up heating the
| atmosphere. This means in a geoengineered world, you have
| less rain.
|
| A reduction in rain might be more important to some
| countries than others - not everyone would want the same
| amount of geoengineering.
| munificent wrote:
| The most cost effective mirrors to cover a large fraction
| of the Earth and reflect back the sun's heat are... the
| polar ice caps. Which we are melting because of climate
| change.
|
| This is one of the main reasons people are so worried about
| it being "too late" to fix climate change. There are
| positive feedback loops like this where a little increased
| heat _causes_ even more rise in temperature.
| Sharlin wrote:
| Yes, in other words: _the darker a thing is, the darker it
| is_. Is someone here actually suprised by the everyday
| phenomenon that dark objects get hotter than light-colored
| ones?
|
| (Edit: I apologize for the uncalled for smugness. But
| "albedo" is not some special physical quantity, it's
| literally a measure of how light/dark colored a material is.
| "Alba" is Latin for "white". Although granted, albedo is
| usually measured across the whole spectrum, not only the
| visible part.)
| Swizec wrote:
| The difference between "not surprised" and "understand why"
| is vast. For example we (humanity) still don't understand
| _why_ gravity works despite not being surprised by its
| existence.
|
| And don't forget the 10,000 rule: https://xkcd.com/1053/
| Sharlin wrote:
| Yes, but GP's quote was not an explanation, it was
| literally saying that "light objects reflect more light".
| Albedo literally means "whiteness" ie. how light
| something is.
| Swizec wrote:
| From GP:
|
| > Traditional asphalt has a low albedo, which means it
| reflects radiation poorly and instead absorbs it
|
| Seems like a pretty good high level explanation of why
| that matters. Darker objects absorb energy instead of
| reflecting it. I'm sure there's more to it than that when
| you get into details.
| Scoundreller wrote:
| Dark will get hotter in sunlight but can be cooler at night
| if the sky is unobstructed.
| capableweb wrote:
| > Dark will get hotter in sunlight but can be cooler at
| night if the sky is unobstructed.
|
| What would the sky be obstructed by? Clouds? How could
| that affect how cool tarmac on the ground gets at night?
| myself248 wrote:
| Yes, clouds.
|
| With a clear sky, you're radiating (based on your own
| temperature) out to the blackness of space, which is
| radiating back at 4 Kelvin. Which is to say, it's
| contributing basically nothing. You're just giving up
| heat to the cosmos.
|
| With a cloudy sky, you're radiating (based on your own
| temperature) out to the bottoms of the clouds, which are
| reflecting your radiation back to someone else on the
| ground, and their own heat is reflecting back to you. And
| such. The cloud looks white in the daytime because it's
| very reflective, so it acts like a mylar blanket to hold
| the heat in.
| ChrisMarshallNY wrote:
| I was told that light reflects heat, and heats more
| quickly, but also radiates badly (cools more slowly).
|
| This is why heatsinks are often painted black.
|
| It is also the reason for all the strange white/black
| colors on rockets.
| onlyrealcuzzo wrote:
| Physics is strange:
|
| > At night, when cloud coverage increases, downwelling
| infrared radiation also increases. So, clouds act like
| space heaters, emitting energy towards the ground.
| Blankets only limit the transfer of heat energy away from
| your skin(convection).
| capableweb wrote:
| Huh, that's very interesting and non-intuitive for a non-
| physicists like me. Thanks for the explanation!
| Sharlin wrote:
| This is what the greenhouse effect is, literally. At
| "thermal IR" wavelengths the sky is a blanket. Cloudy sky
| is even more of a blanket.
| Scoundreller wrote:
| I live near a grape growing are, and they have wind
| turbines to blow air on cool nights slightly above
| freezing because the radiation from the ground to to sky
| can be enough to frost-damage their crops.
|
| So they turn them on the blow the stagnant warmer ambient
| air around and mitigate that.
| ryanmcbride wrote:
| Wow I wish I was as smart as you
| the_only_law wrote:
| If you're lucky there's a course you can overpay for.
| ridgeguy wrote:
| Not necessarily true. It depends on the object's optical
| properties.
|
| I well remember working on my parents' car in Phoenix
| summers. The chromed wrenches on our driveway surface got
| to instant-blister temperatures. Tools with black surfaces
| were uncomfortable to pick up, but were usable.
|
| The chromed tools had a lower absorption of sunlight than
| the black tools, but their IR radiation coefficient was
| even lower. So equilibrium temperature (at which radiated
| energy = incident energy) was much higher for the chromed
| tools.
| WalterBright wrote:
| I was always careful to put my tools in the shade under
| the car :-)
|
| (Used to live in Glendale.)
| onlyrealcuzzo wrote:
| Snow can have an albedo lower than 50% - and non-white sand
| can have an albedo higher than that.
|
| It's not as simple as color.
|
| In particular, there are dark things that have an albedo
| higher than asphalt's 0.05...
| powerhour wrote:
| No need to be an asshole about it. Some folks probably
| don't know the relative darkness of asphalt and tarmac.
| Sharlin wrote:
| But according to GP's numbers, tarmac is _less_ dark than
| asphalt so should get _less_ hot than asphalt. But those
| numbers are suspect and probably only refer to very fresh
| asphalt /tarmac; the albedo aka "lightness" of worn
| asphalt is something like 0.3.
| shadowgovt wrote:
| https://xkcd.com/1053/
| Scoundreller wrote:
| And then you have other factors impacting a surface
| temperature including:
|
| rainfall (you could probably spray the runway and it will
| cool down and be dry quickly...)
|
| Length of day (we're about 1 month past the summer solstice
| in the N. Hemisphere, and days are long in the northern
| latitudes)
|
| Shade (unlikely on runways, they're in the sun all day)
|
| Wind (probably best anywhere on a runway unless it's in a
| valley)
|
| Cloud cover during the _night_ : can't radiate to the
| universe where it's about -273C if clouds are in the way.
| acallaha wrote:
| Can you clarify how night cloud cover factors in? Do clouds
| really substantially reduce the radiative cooling capacity?
| Is that by functionally reflecting radiation back at the
| source (the earth)?
| [deleted]
| GCA10 wrote:
| Broadly yes. It's why deserts have such extreme
| temperature fluctuations between day and night. No clouds
| are part of the reason, as well as very little humidity
| to serve the same heat-retaining/heat-reflecting role.
|
| On my first time in the Nevada desert I was astonished to
| find that I needed a jacket at dawn to stay warm, after
| all kinds of daytime heat. Looking at Elko NV's weather
| this week, it's got highs of 99F/37C and overnight lows
| of 61F/16C
| swores wrote:
| 37C high earlier today and 16C low later tonight are
| coincidentally the exact numbers for my city in the UK.
| Which isn't of course anything like a desert, though the
| whole country is in the middle of a heatwave (and last
| night didn't drop below 20c).
| Scoundreller wrote:
| Radiation is a function of the temperature delta between
| two points.
|
| The sky around where clouds are might be around -20C,
| while outer space is at -273C or so, so you get much more
| radiative heat loss in the latter state (clear sky).
|
| (This is also why you'll see gardeners try to cover their
| plants when there's a "frost warning" even though the
| temperatures won't be going below freezing).
|
| And from the opposite perspective, the sun is really far
| away but incredibly hot, so it transfers heat to us, and
| more as you get closer (and less as you get further
| away).
| Barrera wrote:
| > The runway also "melted" at the RAF Brize Norton, military air
| base in Oxfordshire, west of London, on Monday as the UK
| struggled to cope with the weather.
|
| That word "melted" seems unjustified. CNBC reports:
|
| > The RAF didn't specify why it suspended flights, but a
| spokesperson said "the runway has not melted" as early media
| reports indicated.
|
| https://www.cnbc.com/2022/07/18/london-flights-suspended-aft...
| ibejoeb wrote:
| Totally unjustified, sensational nonsense.
|
| > The UK's highest of 38.7C was recorded in Cambridge in July
| 2019.
|
| This isn't remarkable.
|
| >the record temperature of 100 degrees was reached at Greenwich
| on August 9
|
| This was in 1911, from:
| https://trove.nla.gov.au/newspaper/article/115352761/9911357
| spread_love wrote:
| You mean it wasn't liquified?!
|
| > "following today's high temperatures, a surface defect was
| identified on the runway" https://twitter.com/LDNLutonAirport
| /status/15490520549365719...
|
| > "high surface temperatures caused a small section to lift"
| https://twitter.com/LDNLutonAirport/status/15490713790095114.
| ..
| gnabgib wrote:
| Are you, perhaps, unaware that these are in different units?
| 38.7C is 102F. The UK switched in the 60s to centigrade[0].
| I'd also be suspicious of the accuracy and method of
| temperature collection in 1911.. the Met Office didn't start
| collecting data until 1914, and of the source accuracy..
| Wikipedia[1] seems to suggest 98F (36.7C) and in another
| town. It certainly was extremely hot that August in 1911...
| especially without modern conveniences.
|
| [0]: https://en.wikipedia.org/wiki/Metrication_in_the_United_
| King... [1]:
| https://en.wikipedia.org/wiki/1911_in_the_United_Kingdom
| ibejoeb wrote:
| What's your point? That this is unreliable reporting?
|
| I'll take your word for it that the met office didn't start
| collecting temperature data until 1914. Countless other
| entities didn't either, and none of them were cited either.
| In what year did Wikipedia start collecting temperature
| data?
| notahacker wrote:
| I imagine his point was that there is no reason to
| believe a disputed 100f peak temperature during the
| notorious 1911 heatwave makes today's 104.5f temperature
| advance on 2019's 101.6f peak in a country that does a
| _lot_ of weather reporting unremarkable and unworthy of
| media coverage. Unless one was using the wrong Fahrenheit
| /Celsius conversion factor and somehow didn't realise the
| claimed 1911 temperature was smaller...
| chimprich wrote:
| > Totally unjustified, sensational nonsense.
|
| I wish we had a pithy term for people underplaying
| exceptional events (complacency-mongering?) to show off how
| unflappable they are, because it would be nice to use it in
| this case.
|
| Temperature records being broken are, by definition,
| exceptional events. In this case, the UK's temperature record
| was broken by 1.5C, which is a huge increase.
|
| > This was in 1911
|
| Cherry-picking a data point. There's a very significant trend
| of hotter days and record breaking occurring in the past few
| years. One outlier in a century of data doesn't mean very
| much (and your source of a paragraph from an Australian
| newspaper in 1911 seems to get the value wrong).
| ibejoeb wrote:
| Sorry you can't think of a name to call me.
|
| This is as much cherry-picking as the linked article is.
| It's one measurement.
|
| > source of a paragraph from an Australian newspaper
|
| The link is an Australian paper, too.
| ubercow13 wrote:
| The 38.7C and the 100F were also each one measurement.
| Also it's not just one measurement, at least 33 places
| broke the all time temperature record of the whole
| country today (https://www.bbc.co.uk/news/uk-62217282)
| ibejoeb wrote:
| Right. A temperature measurement on one day is a
| temperature measurement on one, regardless if its 1911 or
| 2022.
| ubercow13 wrote:
| Yes, the trend is in higher maximum temperatures on
| individual outlier hot days. That doesn't make it
| insignificant, so I'm not sure what point you're trying
| to make.
| ibejoeb wrote:
| I'm objecting to the sensationalism and overtly incorrect
| account of the temperature being 40C and the runway
| melting. What good does that do? "Approaching" 40C isn't
| 40C. Depending on who you ask, it was 38C there. I guess
| it's also approaching 50C, why not...
|
| Where are you finding this trend data? It's not in any of
| these materials. Please share if you have it. I've seen
| all sorts of trends, but they always start after the last
| cycle, when it was very hot in '30s.
| ubercow13 wrote:
| I'm not sure if you're just being disingenuous but the
| title says 'as temperatures in UK near 40degC', not
| specifically at the location of the runway, which I guess
| is overtly incorrect in the sense that it's an
| understatement, as it exceeded 40C at multiple places
| today.
|
| This article has at least some stats about hottest days
| going back before the 30's:
| https://www.rte.ie/news/weather/2022/0719/1311135-uk-
| hottest...
| ibejoeb wrote:
| Where was it over 40?
| ubercow13 wrote:
| It's unclear if this list is exhaustive but from
| https://www.bbc.co.uk/news/science-environment-57988023
|
| >Heathrow Airport was the first place to break the 40C
| mark, hitting 40.2C at 12:50 BST but several other places
| also passed 40C during the afternoon, including Gringley
| on the Hill in Nottinghamshire and St James's Park, Kew
| Gardens and Northolt - all in London.
| ibejoeb wrote:
| I think that's the wrong article. It says "we are likely
| to see temperatures of 40C" but doesn't claim that
| anywhere actually did.
| notahacker wrote:
| https://www.bbc.co.uk/news/uk-62217282
| msrenee wrote:
| Maybe I'm nitpicking, but to say it was nearly 40 Celsius when
| the recorded temp was 38 C is an exaggeration. When I lived in
| New Mexico, it would hit 40 C for a couple days at a time in the
| summer. That sucked. Where I'm at in the Midwest, the temp hits
| 38 C for a couple of days at a time in the summer. It's a big
| difference in what kind of precautions you need to take.
|
| I realize they don't have the infrastructure to deal with the
| heat the way we do, but tell me that and then tell me the actual
| temperature reading. Don't round up 2 degrees C like it doesn't
| matter.
| bregma wrote:
| Be thankful they're giving out a temperature within 10 F of the
| actual observation. Where I live the TV news has stopped giving
| out temperature at all and just reports the "feels like"
| humidex index, a made-up number that makes everyone feel smug
| about how well they're bearing the load of global warming.
| pixl97 wrote:
| The humidex is more important for people.
|
| 100F with 10% humidity is hot.
|
| 100F with 90% humidity is deadly.
| timomax2 wrote:
| Typical hot daytime temperature at this time of year is 22 to
| 25. It could easily be 17 or 18. For us 38 is almost 40.
| nicoburns wrote:
| It has hit 40 in a bunch of places in the UK today
| https://www.bbc.co.uk/news/uk-62217282.amp
| msrenee wrote:
| That changes things. I was just going by the article.
| woofcat wrote:
| Wow if you block cookies on this site it 100% blocks you and
| kicks you out.
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