ISCCP BASE DATA FORMATS

DX grid

This is a 0.5 degree square latitude/longitude grid. The grid is 40 x 30 (longitude x latitude) and has a total of 1200 cells. Longitude varies first, and begins at 150W and proceeds eastward to 130W in increments of 0.5 degrees. Latitude begins at 60N and proceeds northward to 75N in increments of 0.5 degrees.

D1 grid

This is a 2.5 degree square latitude/longitude grid. The grid is 8 x 6 (longitude x latitude) and has a total of 48 cells. Longitude varies first, and begins at 150W and proceeds eastward to 130W in increments of 2.5 degrees. Latitude begins at 60N and proceeds northward to 75N in increments of 2.5 degrees.

Special data values

There are two special values that may be present in the data set:

• -1000.0 indicates "no data"
• -500.0 indicates "clear" for those variables that represent cloud parameters

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 factors used are:

• Cloud Amounts: 10
• Cloud Top Pressures: 1
• Cloud Top Temperatures: 10
• Cloud Optical Depths: 100
• Surface Temperatures: 10
• Surface Reflectances: 100
• Cloud/Clear Flags: 1
• Radiance Counts: 1

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

• D1 grid, IEEE floating point: 4,800 bytes
• D1 grid, Scaled integer: 4,800 bytes
• D1 grid, ASCII text: 12,000 bytes
• DX grid, IEEE floating point: 192 bytes
• DX grid, Scaled integer: 192 bytes
• DX grid, ASCII text: 480 bytes

BASE Field Campaign