NUMBER 58

DATE: 06/07/88

Sector Processing Center (SPC):

During April, CSU and ESA collectively processed greater than 92% of A data into B1 and/or B2 data.

Normal operations were reported by ESA and CSU.

ESA reported a small manuever on 3 May at about 1500 GMT to reduce the inclination of METEOSAT's orbit to about 1.35 degrees; this is expected to be the last inclination manuever, due to fuel shortage. The drift rate of inclination is now about 0.9 degrees per year. Although the launch of METEOSAT-P2 is scheduled for June, ESA does not plan to use this satellite for imagery, except in the event of a failure of METEOSAT-2 or significant growth of its inclination. Launch of MOP-1 is currently scheduled for the end of 1988; this satellite will replace METEOSAT-2.

NOAA reported the temporary suspension of the production of NOAA-9 B2 while processing of the vegetation index product is conducted. They are investigating the feasibility of separating the production of these two data products so that an interruption in one does not affect the other. Production was halted on 14 April; a resumption date was not reported.

CSU reported that GOES-6 was in ecllipse from 27 February to 11 April; hence, the 0745 GMT image replaced the 0845 GMT image during this period. NOAA released a new operations plan, that took effect on 5 April, indicating that a full-disk image will be collected every three hours at 45 minutes past the hour.

No reports were received from AES and JMA.

Special Area Processing Center (SAPC):

No reports were received.

Satellite Calibration Center (SCC):

No report was received.

Global Processing Center (GPC):

The GPC continued to receive B1 and/or B2 data and correlative data in a routine manner.

The replacement navigation information for June 84 for GMS still lacked the key piece of information, the subsatellite latitude and longitude, because these images where truncated north of the equator by the scanner problem. Although the B3 data for this month will be delivered to the ICA, the navigation accuracy of all of the images is less than the ISCCP standard, so they will all be labeled as bad quality and will not be used for the cloud climatology. The corrected July 84 GMS B3 data will also be delivered to the ICA.

The NOAA-8 B2 data set for June 84 is so sparse that no B3 data will be produced for that month.

NOAA-9 B3 production has been completed through January 88. The best fit to the VIS channel calibration monitor data, covering three years, indicates a steady decline in sensitivity of 6.6% per year. This is based on the behavior of all the targets that we routinely monitor, as well as the global mean VIS reflectances, and agrees with the result of W. Staylor for the Libyan desert. Inspection of the monthly, global mean IR data for the same time period indicates that the instrument measurements did change slightly but that the on-board IR calibration removed the trends. Some small anomalies in the IR calibration, including the one noticed by the SCC in October 1986, are being investigated. The NOAA-9 B3 data tapes will now be processed to remove the VIS calibration drift and to correct any IR anomalies. Delivery of NOAA-9 B3 should be completed by the end of June.

Comparison of the calibration monitor results for October 86 with the aircraft calibration obtained during the FIRE Cirrus Intensive Field Observations is completed. This comparison included the results of W. Staylor, discussed above, the results of several indirect calibrations, especially those performed by C. Gautier using White Sands as a target, and additional aircraft data from late 1985 and early 1988. The results of C. Gautier are for GOES-4, 5, and 6, as well as NOAA-7 and 9; hence, the ratios of GOES to NOAA will also be compared to the SCC results. The ISCCP VIS radiance calibration, which was the nominal calibration for Channel 1 on NOAA-7, will be changed for cloud production to

where OLD A is the "albedo" (scaled radiance) obtained by applying the NOAA coefficients to VIS counts for NOAA-7 data in July 1983. To obtain this comparison, the NOR A (normalized to NOAA-7 "albedo") for NOAA-9 in October 1986 is calculated from the NOM A (nominal NOAA calibration for NOAA-9) by

where the coefficients account for the decline of NOAA-9 sensitivity and the ratio of NOAA-9 to NOAA-7 response.

B3 production for the geostationary satellite data beyond January 1985 can now begin. While the NOAA-9 B3 tapes are being reprocessed, only two satellites (GOES and GMS) can be processed; upon completion of the NOAA-9 data, all three data sets (GOES, GMS, METEOSAT) will be processed in parallel. We expect to be able to process about one year of B3 data for each satellite per month.

Digital sea ice data for 1985 and 1986 have been received from NOAA. Production of the ice/snow data product is underway and delivery is expected by next week.

Minor changes in the TOVS data tape format and documentation have been completed. All processing of the data for 1983 and 1984 has also been completed; these data should be delivered to the ICA next week. The production code has also been installed in the CLIPS system so that production of data for 1985 can begin.

The special data sets for the Polar Workshop for January and July 1984 have been completed and shipped to Prof. Raschke.

The NOAA-9 BX/CX data sets for the FIRE Cirrus and Marine Stratus IFO periods (October/November 1986 and July 1987) have been completed. These data will be delivered to the FIRE archive later this month, after a FIRE format has been developed and documented. The data for October 86 will be re-processed next month, using the final absolute VIS calibration, for the participants in the Surface Radiation Budget Pilot Study. The GOES data for the two FIRE IFO periods will be processed later in the summer, once the B3 data are completed.

Production of the final versions of the July 83 and Jan 84 C1 data will commence next week. Production of the special C1 data set for WGNE and the ERBE project (April 1985) is planned for July.

ISCCP Central Archive (ICA):

The ICA continued to receive B1 data from JMA, CSU, ESA, and NOA in a routine manner. Apparently no B1 data have ever been received from AES; this matter is being investigated.

The health of GMS-3, METEOSAT-2, GOES-6, GOES-7, NOAA-9 and NOAA-10 remained good. On 9 May the signal from Channel 3 (3.7 m) on the NOAA-10 AVHRR became very noisy; a change in instrument configuration returned performance to normal last week. NOAA-H is on-schedule for a launch in August 1988. METEOSAT-P2 is scheduled on the next Ariane launch in June 1988.

Obtaining NOAA-10 B1/B2 data over the Indian sector starting in December 1986.

Arranging for the delivery of INSAT B1 data.

Completing BC data for 1987.

Delivering all B3 data for 1985 and 1986.

Delivery of special C data sets for FIRE, the WGNE, and ERBE.

Beginning delivery of the final version of C1 data.