From 45d3cdd71ef77ab4f66a4dd2011c9fbb403e8cac Mon Sep 17 00:00:00 2001 From: Constantine Khrulev Date: Mon, 12 Oct 2020 09:49:17 -0800 Subject: [PATCH] Document PISM's interpretation of forcing inputs - 2D fluxes: piecewise-constant in time - 2D (other): piecewise-linear in time - scalar (with time bounds): piecewise-constant - scalar (without time bounds): piecewise-linear --- doc/sphinx/climate_forcing/time.rst | 19 ++++++++++++------- 1 file changed, 12 insertions(+), 7 deletions(-) diff --git a/doc/sphinx/climate_forcing/time.rst b/doc/sphinx/climate_forcing/time.rst index 30c80c855f..99f0826bab 100644 --- a/doc/sphinx/climate_forcing/time.rst +++ b/doc/sphinx/climate_forcing/time.rst @@ -50,10 +50,18 @@ appropriate in forcing files. Using time bounds in forcing data +++++++++++++++++++++++++++++++++ -PISM interprets climate forcing data as piecewise-constant in time. A forcing file is -required to contain time bounds corresponding to each record. +To make :ref:`balancing the books ` possible, PISM interprets *fluxes* +(examples: top surface mass balance, precipitation, sub shelf mass flux) as +piecewise-constant in time. A forcing file is required to contain time bounds +corresponding to each record. -PISM follows the CF (Climate and Forecasting) meta-data conventions. The ``ncdump -h`` +Other 2D input fields (examples: ice surface temperature, near-surface air temperature) +are interpreted as piecewise-linear in time. + +*Scalar* time-dependent inputs are interpreted as piecewise-constant in time if an input +file contains time bounds and piecewise-linear otherwise. + +PISM supports time bounds specified according to `CF Conventions`_. The ``ncdump -h`` output from a conforming file would look similar to: .. code-block:: none @@ -74,7 +82,4 @@ output from a conforming file would look similar to: The :var:`time_bounds` variable stores the starting and the ending time for each interval in the forcing. This variable is assumed to have the same units as the :var:`time` -variable it is associated with, which is why its arguments are not set in this example. - -Please see the `CF Conventions`_ document for details. - +variable it is associated with, which is why these attributes are not set in this example.