Taylor, Karl E., David Williamson, and Francis Zwiers
September 2000, 28 pp.
In many atmospheric general circulation model (AGCM) simulations, the
sea surface temperature (SST) and sea-ice concentration (i.e., percentage
of area covered by sea ice) are both prescribed, based on observations.
In particular this experimental design is fundamental to the Atmospheric
Model Intercomparison Project simulations. For AMIP, observed monthly mean
SSTs and sea-ice concentration have been compiled for the period January
1979 through February 1996 and also for the month preceding and for several
months following the designated AMIP II period. These observed monthly
means do not constitute the official AMIP II "boundary conditions," but
the boundary conditions are based on them, as explained in this brief report.
In AMIP II the SST and sea-ice concentration boundary conditions should
be specified such that the monthly means computed from the model output
precisely agree with the observed monthly means. There are several ways
to assure compliance with this AMIP II requirement, but for most models
which rely on linear interpolation between monthly values, appropriate
AMIP II boundary condition data sets can be obtained from the Program for
Climate Model Diagnosis and Intercomparison (PCMDI).
This report contains a description of and justification for the procedure
recommended here for preparing and applying the AMIP II boundary condition
data sets.(pdf file)