tchanges-05-06.rst - pism - [fork] customized build of PISM, the parallel ice sheet model (tillflux branch)
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       tchanges-05-06.rst (3942B)
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            1 Changes from 0.5 (May 2012) to 0.6
            2 ==================================
            3 
            4 Basal strength and basal hydrology
            5 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
            6 
            7 -  A significant change to the model physics for till: effective
            8    pressure in till is now computed by empirically-based (and
            9    exponential) formula from [``Tulaczyketal2000``\ ] relating amount in
           10    till to effective pressure.
           11 -  New mass-conserving subglacial hydrology model.
           12 
           13 Marine ice sheet modeling
           14 ~~~~~~~~~~~~~~~~~~~~~~~~~
           15 
           16 -  Implement a parameterization of the melange back pressure as a part
           17    of the stress boundary condition at the ice shelf front.
           18 -  Implement fracture density model and fracture-induced ice softening
           19    (see [``AlbrechtLevermann2012``\ ]).
           20 -  Parameterization of the sub-grid position of the grounding line and
           21    related improvements (see
           22    [``Feldmannetal2014``,\ ``Gladstoneetal2012``]).
           23 -  MISMIP3D example (see [``MISMIP3d2013``\ ]), grounding line
           24    reversibility.
           25 -  Fixes related to the handling of the grounding line (i.e. driving
           26    stress, etc)
           27 -  Use an implementation of a serial two-scan connected-component
           28    algorithm to identify icebergs.
           29 -  Report cumulative discharge (calving) flux as a 2D field.
           30 
           31 Climate inputs and ocean inputs
           32 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
           33 
           34 -  ``PISMSurfaceModel`` returns climatic mass balance in
           35    ``[kg m-2 s-1]``
           36 -  Remove ``pclimate``; add the ``-test_climate_models`` option.
           37 -  ``-part_grid`` extended to grounded marine termini.
           38 -  Require time bounds in time-dependent climate forcing.
           39 -  Improve the PDD scheme. (Keeps track of the snow depth during the
           40    year to choose PDD factors but does not model multi-year snow cover.)
           41 -  Implement the 3-equation sub-shelf melt parameterization (see
           42    [``Hellmer1998``\ ]).
           43 -  Implement caching surface and ocean models ``-ocean ...,cache`` and
           44    ``-surface ...,cache``. (Update boundary inputs every X years but
           45    include interannual variability.)
           46 -  Remove ``EISMINT-Greenland``.
           47 
           48 Inverse modeling
           49 ~~~~~~~~~~~~~~~~
           50 
           51 -  Inverse modeling tools *are* a part of the release now.
           52 
           53 Energy
           54 ~~~~~~
           55 
           56 -  New bootstrapping heuristic filling ice temperature at depth from
           57    surface mass balance (if available).
           58 -  Allow "regridding" enthalpy from files containing ice temperature and
           59    liquid water fraction.
           60 -  Allow cold flow laws in the enthalpy mode and GPBLD in the cold mode
           61    (same as Paterson-Budd).
           62 -  Corrected basal boundary condition in the enthalpy system.
           63 
           64 Usability
           65 ~~~~~~~~~
           66 
           67 -  Implement poor man's parallel I/O, with compression
           68 -  Ensure "continuity" in time of reported cumulative diagnostic fields.
           69 -  Let the user precisely specify the dates corresponding to the run
           70    (``-time_file``).
           71 -  Many more diagnostic quantities; use ``-list_diagnostics`` to see.
           72 -  PISM keeps track of options and parameters that were set but were not
           73    used.
           74 -  Use projection info to compute latitude and longitude bounds.
           75    (Reduces post-processing needed to work with PISM's output.)
           76 
           77 Miscellaneous
           78 ~~~~~~~~~~~~~
           79 
           80 -  Improve mass conservation and mass transport.
           81 -  New validation example based on laboratory experiment with xanthan
           82    gum. Uses millimeter grid spacing and shows configurability of PISM.
           83 -  Implement a "constant 2D velocity" stress balance object (for testing
           84    and prescribing sliding)
           85 
           86 Under the hood
           87 ~~~~~~~~~~~~~~
           88 
           89 -  Improve the build system.
           90 -  Switch to PETSC 3.3 or 3.4, stop supporting 3.2.
           91 -  Switch to
           92    `UDUNITS-2 <http://www.unidata.ucar.edu/software/udunits/>`__.
           93 -  Require `FFTW-3 <http://www.fftw.org>`__ to build PISM.
           94 -  Use `CalCalcs <http://meteora.ucsd.edu/~pierce/calcalcs/>`__ for
           95    proper calendar support.
           96 -  Remove the Debian [meta-] package.
           97 -  Clean up command-line options selecting sub-models (calving, stress
           98    balance, energy, basal yield stress).
           99 -  Better ``SSAFD`` recovery logic; save model state on failure.
          100 -  Use non-zero initial guess in the SSAFD KSP solver.
          101 -  Improved basal yield stress code.
          102