trun-1-watching.rst - pism - [fork] customized build of PISM, the parallel ice sheet model (tillflux branch)
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       ---
       trun-1-watching.rst (2805B)
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            1 .. include:: ../../global.txt
            2 
            3 .. _sec-watchrun:
            4 
            5 Watching the first run
            6 ----------------------
            7 
            8 As soon as the run starts it creates time-dependent NetCDF files ``ts_g20km_10ka.nc`` and
            9 ``ex_g20km_10ka.nc``. The latter file, which has spatially-dependent fields at each time,
           10 is created after the first 100 model years, a few wall clock seconds in this case. The
           11 command ``-extra_file ex_g20km_10ka.nc -extra_times -10000:100:0`` adds a
           12 spatially-dependent "frame" at model times -9900, -9800, ..., 0.
           13 
           14 To look at the spatial-fields output graphically, do:
           15 
           16 .. code-block:: none
           17 
           18    ncview ex_g20km_10ka.nc
           19 
           20 We see that ``ex_g20km_10ka.nc`` contains growing "movies" of the fields chosen by the
           21 ``-extra_vars`` option. A frame of the ice thickness field ``thk`` is shown in
           22 :numref:`fig-growing` (left).
           23 
           24 The time-series file ``ts_g20km_10ka.nc`` is also growing. It contains spatially-averaged
           25 "scalar" diagnostics like the total ice volume or the ice-sheet-wide maximum velocity
           26 (variable ``ice_volume_glacierized`` and ``max_hor_vel``, respectively). It can be viewed by
           27 running
           28 
           29 .. code-block:: none
           30 
           31    ncview ts_g20km_10ka.nc
           32 
           33 The growing time series for ``ice_volume_glacierized`` is shown in :numref:`fig-growing`
           34 (right). Recall that our intention was to generate a minimal model of the Greenland ice
           35 sheet in approximate steady-state with a steady (constant-in-time) climate. The measurable
           36 steadiness of the ``ice_volume_glacierized`` time series is a possible standard for steady
           37 state (see :cite:`EISMINT00`, for exampe).
           38 
           39 .. figure:: figures/growing-thk-ivol-g20km.png
           40    :name: fig-growing
           41 
           42    Two views produced by ``ncview`` during a PISM model run.
           43 
           44    :Left: :var:`thk`, the ice sheet thickness, a space-dependent field, from file
           45           ``ex_g20km_10ka.nc``.
           46    :Right: :var:`ice_volume_glacierized`, the total ice sheet volume time-series, from file
           47            ``ts_g20km_10ka.nc``.
           48 
           49 At the end of the run the output file ``g20km_10ka.nc`` is generated.
           50 :numref:`fig-firstoutput` shows some fields from this file. In the next subsections we
           51 consider their "quality" as model results. To see a report on computational performance,
           52 we do:
           53 
           54 .. code-block:: none
           55 
           56    ncdump -h g20km_10ka.nc |grep history
           57    :history = "user@machine 2017-10-04 19:16:08 AKDT: PISM done.  Performance stats: 0.1784 wall clock hours, 0.7136 proc.-hours, 14005.0054 model years per proc.-hour.\n",
           58 
           59 .. figure:: figures/g20km-10ka-usurf-csurf-mask.png
           60    :name: fig-firstoutput
           61 
           62    Fields from output file ``g20km_10ka.nc``.
           63 
           64    :Left: :var:`usurf`, the ice sheet surface elevation in meters.
           65    :Middle: :var:`velsurf_mag`, the surface speed in meters/year, including the 100 m/year
           66             contour (solid black).
           67    :Right: :var:`mask`, with 0 = ice-free land, 2 = grounded ice, 4 = ice-free ocean.