FD On-Line Data Formats and File Naming Convention
Data is available for downloading on either EQ or SQ grids, in either IEEE floating point, scaled integer, or ASCII text format.
EQ grid
This is a 2.5 degree Equal Area grid, and is the grid on which the data is produced. The ISCCP equal-area grid contains 6596 grid boxes; 0 degrees latitude, 0 degrees longitude is a box corner. Boxes are numbered sequentially, beginning at the South Pole and the Greenwich Meridian, and proceeding eastward through the latitude zone, then northward to the next latitude zone.
SQ grid
This is a 2.5 degree Square latitude/longitude grid, and is usually used for display purposes. The grid is 144 x 72 (longitude x latitude) and has a total of 10368 boxes. 0 degrees latitude, 0 degrees longitude is a box corner. Longitude varies first, and begins at -180 degrees and proceeds eastward to +180 degrees. Latitude begins at -90 degrees and proceeds northward to +90 degrees.
IEEE floating point format
Data is written using the IEEE standard for floating-point representation.
Scaled integer format
Data is written as scaled integers. Scale factor used is: 10.
ASCII text format
Data is written 80 characters per record. Each record contains values for 8 grid boxes, each with a field width of 10 characters. The precision is 3 decimal places.
File sizes
- EQ grid, IEEE floating point: 26384 bytes
- EQ grid, Scaled integer: 26384 bytes
- EQ grid, ASCII text: 65960 bytes
- SQ grid, IEEE floating point: 41472 bytes
- SQ grid, Scaled integer: 41472 bytes
- SQ grid, ASCII text: 103680 bytes
FILE NAMING CONVENTION
If you are downloading data from our ISCCP anonymous ftp site, note the following file naming conventions:
NET FLUX FLUX --------------------- ----------------------- FDAVGTTT__SSFFVVV.GRD FDAVGTTT__SSFFVVVCC.GRD FDYYYYMM__SSFFVVV.GRD FDYYYYMM__SSFFVVVCC.GRD
where TTT and/or YYYYMM indicate the time period; SS is the spectral range (LW: Longwave, SW: Shortwave, TL: Total); FF is the flux variable (FL: Full Sky Net Flux, CD: Cloudy Sky Net Flux, CR: Clear Sky Net Flux, CE: Cloud Effect, XX: All-Scene); VVV is the spatial/vertical position (TOA: Top of the atmosphere, ATM: in the atmosphere, SFC: at the surface); and CC is the flux component (UW: Upwelling, DW: Downwelling).
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