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Model Spatial and Temporal Coverage

 

The standard version of the QTCM1 provides coverage from tex2html_wrap_inline1285 S to tex2html_wrap_inline1285 N in latitude and coverage over all longitudes. The grid has dimensions tex2html_wrap_inline1289 equal to 64 tex2html_wrap_inline1291 32. The east/west boundaries are periodic, and the north/south boundaries are solid walls, with sponge layers from tex2html_wrap_inline1293 S to tex2html_wrap_inline1285 S, and tex2html_wrap_inline1293 N to tex2html_wrap_inline1285 N. Thus, the grid spacing is 5.625 [i.e. tex2html_wrap_inline1301 ] degrees longitude and 3.75 [i.e. tex2html_wrap_inline1303 ] degrees latitude.

Following FORTRAN convention, the first index increments in the zonal (x) direction with increasing longitude in the eastward direction, beginning at 0 degrees E longitude. The second index increments in the meridional (y) direction with increasing latitude northward, beginning at tex2html_wrap_inline1309 S latitude (i.e. tex2html_wrap_inline1311 latitude). Thus:

grid box (1,1) is centered at tex2html_wrap_inline1313 E longitude, tex2html_wrap_inline1311 latitude
grid box (2,1) is centered at tex2html_wrap_inline1317 E longitude, tex2html_wrap_inline1311 latitude
grid box (2,2) is centered at tex2html_wrap_inline1317 E longitude, tex2html_wrap_inline1323 latitude
grid box ( tex2html_wrap_inline1325 ) is centered at tex2html_wrap_inline1327 E longitude, tex2html_wrap_inline1309 latitude

The spatial array sizes NX and NY are set in the header file hgrid.h. Higher resolution can be easily achieved by modifying hgrid.h and subroutine parinit. Higher resolution boundary data sets can be created using a package released along with this version of model. See section 1.4.3 for details. Section gif has a more complete description of the model grid. A new parameter YB is added in the hgrid.h. It specifies the meridional boundary of model domain in degrees. Therefore, the domain is stretchable up to poles. However, model performance is sensitive to certain parameters when the global domain is used. Further tests are needed, since some of the approximations used in the parameterizations may be outside their domain of validity at high latitudes.



Johnny Wei-Bing Lin
Thu Sep 9 13:11:12 PDT 1999