NUMBER 53

DATE: 01/06/88

Sector Processing Center (SPC):

During November, ESA and JMA collectively processed greater than 97% of A data into B1 and/or B2 data. AES processed 69% of the A data into B1/B2.

Normal operations were reported by ESA, JMA and AES.

AES reported data losses on 19 November caused by installation of an optical disk drive and on 27/28 November caused by a power outage.

No report was received from CSU or NOA.

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 from JMA, ESA, CSU, AES and NOA and correlative data from NOAA/NESDIS in a routine manner.

B3 data for GOES-6 from November 1983 through October 1984 were delivered to the ICA. However, QC inspection revealed a brief change in the calibration of the IR channel, associated with the failure of a heater in the instrument. This is revealed by an apparent 2 K decrease in the image mean IR radiance that occurs abruptly on 22 February 1984. The image mean brightness temperature appears to return to "normal" levels in early March. The calibration will be adjusted for this two week period and new B3 data tapes submitted to the ICA next week.

Production of the GMS B3 data has been completed through February 1984 and is continuing. Delivery to the ICA will begin next week.

Production of NOAA-8 B3 has been completed for one month of data; this production will continue in parallel with that of the GMS data. These data will not be delivered, however, until the calibration has been checked against that of NOAA-7 over the whole time period.

Final information from NOAA indicates that there is no southern hemisphere snow data produced operationally (the document obtained by the GPC was a feasibility study, but no production was implemented). Therefore, the snow/ice data set has been completely processed (with no southern hemisphere snow information), merged and mapped. After completion of the tape documentation, these data for July 1983 through December 1984 will be sent to the ICA. No sea ice data for subsequent years has been received as yet.

The final TOVS processing software is complete. After collecting data over a whole day and replicating nearby observations (if the topography is not too different), daily TOVS maps are typically missing for about 25% of the globe. Use of the monthly average of the daily maps fills almost all of these holes; thus, only about 1% of the temperature and humidity data for a given day comes from the Oort climatology. After some final tests of the resultant temperature and humidity fields, production should begin later this month.

Test runs of the revised cloud algorithm are continuing, with special attention being given to the polar regions. Important refinements that have been accomplished are as follows. (1) Non-linear VIS and IR thresholds have been defined to maintain constant optical thickness and top altitude ranges in the cloud statistics. (2) Ice or snow cover, land-locked water bodies, and rugged topography have been identified as important sub-classes of scene type; the algorithm logic now treats these scene types with a more conservative logic than for other land and ocean locations. (3) Land type (vegetation, water) has been used to eliminate residual cloud contamination in the visible clear radiances. All that remains are to tune the "branching ratios" in the clear sky logic and to tune the adjustment parameters and thresholds.

Final tests of the radiation code have been completed, although some further investigation of the cloud top height calculation for optically thin clouds is being conducted.

Changes in the diagnostic step that produces the C1 data will begin next week.

ISCCP Central Archive (ICA):

The ICA continued to receive B1 data from JMA, CSU, ESA, AES and NOA in a routine manner.