NUMBER 90

DATE: 02/06/91

Sector Processing Center (SPC):

During December, NOA, ESA and JMA processed greater than 93% of A data into B1/B2 data.

Normal operations were reported by NOA and JMA. No report was received from AES.

ESA reported decontamination of the IR channels on METEOSAT-4. Images from METEOSAT-3 were substituted for the period 0830 UTC on 11 December 90 through 0930 UTC on 13 December 90. A slower than normal temperature recovery of the METEOSAT-4 instrument caused unreliable calibrations for the three images at 1200, 1500 and 1800 UTC on 13 December 90.

CSU shipped B2 data for INSAT for January - December 86 to the GPC. These radiances have been normalized by comparison to the B3 radiances from METEOSAT and GMS, using coincident, co-located measurements. Rates of successful processing into Stage B2 for 86 are as follows: January - 100.0%, February - 94.6%, March - 95.2%, April - 93.3%, May - 88.7%, June - 91.7%, July - 87.1%, August - 85.5%, September - 45.0%, October - 90.3%, November - 96.7% and December - 50.0%.

Special Area Processing Center (SAPC):

No reports were received.

Satellite Calibration Center (SCC):

BC data are now complete through July 90. Additional BC data for GOES-7 for August and September 90 were received. A rough draft of a manuscript describing the normalization procedure was received at the GPC. Combining this with a description of the final calibration adjustments performed at the GPC will produce a paper for submission to a scientific journal documenting the ISCCP calibration procedures.

Global Processing Center (GPC):

The GPC continued to receive B2 data, BC data and correlative data in a routine manner.

Production of NOAA-11 (preliminary) B3 data is current.

Production of NOAA-10 (preliminary) B3 data is current. The calibration of Channel 1 on NOAA-10 underwent a sudden change in late May 89; the transition appears to be gradual over about one to two weeks. The original normalization coefficients being used for NOAA-10 since December 86 were a slope = 0.85 and an intercept = + 0.002. In addition a trend correction has been applied. If no change had occurred, the correction to NOAA-10 Channel 1 calibration in July 89 would have been: slope = 0.956, intercept = + 0.002. These coefficients had to be changed to: slope = 0.931, intercept = - 0.004. Although the brighter targets darkened slightly, darker targets, like the clear ocean, became much brighter. Apparently, the long-term drift in the calibration also ceased at this time.

Production of METEOSAT (preliminary) B3 data is current.

Production of GOES-7 (preliminary) B3 data is current. Re-processing to remove small offsets between the VIS and IR images and re-calibration of GOES-7 B3 data have been completed through June 88 and the data delivered to the ICA. GOES-7 data after January 89 have all been re-processed to remove the effects of occasional switching back and forth between the old and new IR calibration tables.

Production of GOES-6 (preliminary) B3 data is completed. The error associated with the same table switching for GOES-6 has been corrected and all of the B3 data from April 87 through October 88 have been replaced.

Production of GMS-4 (preliminary) B3 data is current.

All B3 data is complete and shipped to the archives through June 88. THIS COMPLETES THE FIRST FIVE YEARS OF STAGE B3 DATA!

B2 data for INSAT for January - December 86 have been received.

Production of TOVS correlative data has been completed for 90 and shipped to the ICA. Sea ice correlative data have been received for 89 and snow correlative data have been received for 89 and 90.

C1 data for May and June 87 have been completed and shipped to the ICA.

ISCCP Central Archive (ICA):

The ICA continued to receive B1 data from NOA, AES, ESA, and JMA and B3 and C data from the GPC in a routine manner.