After the model grid has been established, the bottom topography, initial values of temperature and salinity, and the initial wind stress are determined within prep.F. The code used to estimate these quantities is stored in the PREP/SUBS subdirectory and is inserted into the file prep.F using #include C-preprocessor directives. The files from PREP/SUBS that are included in prep.F during the normal procedure for setting up a North Atlantic simulation are discussed below.
Hcdf.h holds the code to read in etopo5 (National Geophysical Data Center 1985) data from a remote file that is in netcdf format. It determines the average values of the four etopo5 points that are closest to the centers of each grid cell and uses this average to estimate the bottom depth for that location. If smoothing of the bottom depth is desirable, the required code may be included in Hcdf.h.
TScdf.h holds the code required to read Levitus (ref?) temperature and salinity data from a netcdf file and interpolate to the model grid. After reading in the Levitus data, a horizontal Poisson smoother is used to smoothly interpolate or extrapolate to fill all grid locations, even those on land. The original data is not modified by this interpolation routine. Once the horizontal grid has been filled, temperature and salinity are interpolated to the lon/lat positions of the center points of the model grid cells at the standard levels used by Levitus. Finally, the data is vertically interpolated from the standard levels used by Levitus to the mid-levels of the cells used in the numerical model.
STRcdf.h holds the code to read Hellerman and Rosenstein (ref?) wind stress values from a netcdf file and horizontally interpolate this data to the model grid.
Sfce_flux.h holds the code to read in COADS (ref?) data for surface heat flux from a netcdf file, and interpolate this data to the model grid. This data includes monthly mean values of surface heat flux Qs and the rate of change of Qs with sea surface temperature dQdSST. This information can be used to specify the model's surface heat flux in terms of the climatological estimates of the heat flux plus the deviation of the model's surface temperature from the estimates obtained from the Levitus data.