tindex.rst - pism - [fork] customized build of PISM, the parallel ice sheet model (tillflux branch) (HTM) git clone git://src.adamsgaard.dk/pism (DIR) Log (DIR) Files (DIR) Refs (DIR) LICENSE --- tindex.rst (2984B) --- 1 .. include:: shortcuts.txt 2 3 .. _sec-climate-forcing: 4 5 Climate forcing 6 =============== 7 8 PISM has a well-defined separation of climate forcing from ice dynamics. This manual is 9 about the climate forcing interface. 10 11 By contrast, most options documented in the :ref:`sec-users-manual` control the ice 12 dynamics part. The User's Manual does, however, give an :ref:`overview of PISM's surface 13 (atmosphere) and ocean (sub-shelf) interfaces <sec-climate-inputs>`. At these interfaces 14 the surface mass and energy balances are determined and/or passed to the ice dynamics 15 code. 16 17 To get started with climate forcing usage we need to introduce some language to describe 18 parts of PISM. In this manual a *component* is a piece of PISM code, usually a C++ class. 19 A combination of components (or, in some cases, one component) makes up a "model" --- an 20 implementation of a physical/mathematical description of a system. 21 22 PISM's climate forcing code has two kinds of components. 23 24 - Ones that can be used as "stand-alone" models, such as the implementation of the PDD 25 scheme (section :ref:`sec-surface-pdd`). These are *model components*. 26 - Ones implementing "corrections" of various kinds, such as lapse rate corrections 27 (sections :ref:`sec-surface-elevation-change` and :ref:`sec-atmosphere-elevation-change`) or 28 ice-core derived offsets (sections :ref:`sec-surface-delta-t` and 29 :ref:`sec-ocean-delta-sl`, for example). These are called *modifier components* or 30 *modifiers*. 31 32 Model components and modifiers can be chained as shown in 33 :numref:`fig-climate-input-data-flow`. For example, 34 35 .. code-block:: none 36 37 -ocean constant,delta_T -ocean_delta_T_file delta_T.nc 38 39 combines the component providing constant (both in space and time) ocean boundary 40 conditions with a modifier that applies scalar temperature offsets. This combination 41 one of the many ocean models that can be chosen using components as building blocks. 42 43 Section :ref:`sec-forcing-examples` gives examples of combining components to choose 44 models. Before that we address how PISM handles model time (Section 45 :ref:`sec-model-time`). 46 47 .. admonition:: Summary of the main idea in using this manual 48 49 Setting up PISM's climate interface *requires* selecting one surface and one ocean 50 component. The surface component may use an atmosphere component also; see 51 :numref:`fig-climate-input-data-flow`. Command-line options :opt:`-atmosphere`, 52 :opt:`-surface` and :opt:`-ocean` each take a comma-separated list of keywords as an 53 argument; the first keyword *has* to correspond to a model component, the rest can be 54 "modifier" components. Any of these options can be omitted to use the default 55 atmosphere, surface or ocean model components, but one has to explicitly choose a model 56 component to use a modifier. Model components and modifiers are chained as in 57 :numref:`fig-climate-input-data-flow`. 58 59 .. toctree:: 60 61 time.rst 62 63 examples.rst 64 65 testing.rst 66 67 surface.rst 68 69 atmosphere.rst 70 71 ocean.rst