ISCCP CATALOG OF DATA AND PRODUCTS Section 3.4

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3.4 GOES-WEST

The GOES-West (135W) B1 data sets were produced by the Cooperative Institute for Research in the Atmosphere (CIRA) at the Colorado State University (CSU). The data sets were produced from full disk calibrated GOES-West data.

From July 1983 to January 1989, GOES-6 data were processed by CIRA. The 8 x 8 array of visible pixels were averaged to simulate an 8 x 8 km visible detector. The eight bit product has lower noise than the 64 six-bit input numbers. The 10.2 to 12.5 micron IR channel was saved to the archive with an 8 x 8 sampling rate.

From September 1994 into January 1996, CIRA processed GOES-7 data for ISCCP as this satellite was moved to the GOES-West position after the first of the GOES-NEXT series was launched and deployed in the GOES-East position.

From the new GOES-NEXT series, GOES-9 replaced GOES-7 as the western GOES in January 1996. GOES-7 was in operation for over nine years before being placed in standby mode. CIRA processed GOES-9 data from January 1996 until July 1998, when trouble with the momentum wheels forced NOAA to place GOES-9 in standby mode. GOES-10 was already in storage-mode over the United States after NASA and NOAA had conducted a series of science tests. GOES-10 was ready to replace either GOES-8 or GOES-9. Once GOES-9 started showing signs of trouble, NOAA restarted imaging operations on GOES-10 and moved it towards the GOES-West position. No imaging data over the western United States was lost during this transition from GOES-9 to GOES-10.

From 1994 to the present, the raw data from the GOES-NEXT satellites have been received by the ground station at Wallops Island, Virginia and are processed into GOES Variable (GVAR) format before being retransmitted back to the satellite. The data are then directed to various ground stations.

The GVAR data represent the A-level data used for processing the B1 data. These data frames consist of IR data transmitted from seven IR detectors to cover four infrared bands ( 3.8-4.0, 6.5-7.0, 10.2-11.2 and 11.5-12.5 microns) and visible data from eight visible detectors (0.52-0.72 micron band). The infrared data have a resolution of nominally 4 x 4 km near nadir, except the water vapor band (6.5-7.0 microns, which has an 8 x 8 km resolution). The visible data have a resolution of 1.0 x 0.5 km near nadir.

All five bands from the imager are converted to B1 and B2 data at three hour intervals (0000, 0300, 0600, 0900, 1200, 1500, 1800 and 2100 UTC) and archived on IBM 3480 cartridges with two days worth of data per cartridge. Two additional products are included in each time interval. They are variance of the visible and infrared bands to provide a measure of the homogeneity. This GVAR data stream has 10-bit data for all five imager channels. CSU has changed the data to 8- bit versions to match the ISCCP convention for B1 and B2 data. The visible data is a 7 x 4 pixel average to match the 4 x 4 km resolution of the IR channels. The visible variance saved is the standard deviation of these 28 numbers. The IR variance is calculated from the 4 neighboring pixels. The B1 data represents a 9 km x 8 km sampling of the 4 x 4 km IR data with matching average visible pixels.

Additional information about CSU's collection procedures and source code to read the B1 and B2 formats can be found on the Internet at the following URL: http://www.cira.colostate.edu/climate/ISCCP/ISCCPSPC.HTM.