NUMBER 50

DATE: 10/05/87

Sector Processing Center (SPC):

During August, ESA and JMA collectively processed greater than 99% of A data into B1 and/or B2 data. AES processed 73% of A data in August. No processing matix was sent by NOA.

Normal operations were reported by ESA, JMA and NOA.

JMA reported discovery of a navigation error in the AC data sets since March 1987. The problem in the software that produces AC data has now been corrected; all corrected AC data will be delivered in October.

No report was received from CSU.

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.

The repeat of the NOAA-7 monitor results with the corrected code has been completed through January 1985. No changes in previously reported conclusions are implied.

The final tests of the NOAA-9 calibration to NOAA-7 led to an improved correspondance of reflectances for all surface types using the following:

Although the slope coefficient differs by 5% from the previously reported value, the actual difference in measured radiances is only about 1%. B3 data production for NOAA-9, using this calibration, has started; data for January and February 1985 have been completed.

The final NOAA-8 calibration results required no change; that is,

Production of NOAA-8 B3 data is planned after completion of one year of NOAA-9 and the first 19 months of GMS data are completed.

The QC backlog for GOES-5 data from July 1983 through June 1984 has been eliminated; the first two steps of the QC inspection having been completed. Final inspection of the suspicious images (last step) has been completed for all the GOES-5 B3 data and for the first eight months of GOES-6 B3 data. In addition, the first month of GMS B3 data has also been quality inspected.

The final problems with navigation of the GMS data have been resolved; a subtle error in the GPC navigation code was found that produced the one pixel offset in the results. Final optimization of the code will be completed in the next two weeks. Production of the GMS B3 data will begin in late October.

Remapping of the sea ice data for 1983 and 1984 has been completed. Documentation of the snow data format has been received from NOAA; remapping and merging of the snow data with the sea ice data should begin by the end of October.

The implemented changes to the cloud detection step of the algorithm are still being tested to insure that the majority of the results remain unchanged. A correction procedure for sun glint in the polar orbiter data has been devised and added to improve the VIS clear sky results. The testing of VIS clear sky by surface type (ocean, desert, vegetation, etc.) has produced the expected improvement in the clear sky results. Testing of these changes should be completed next week. Changes to the detection step that remain to be done are to implement the non-linear IR threshold (linear in radiance), to implement improved angle correction procedures (already developed), and to implement the snow/ice-dependent procedures. The minor changes in the radiative analysis step are underway and should be completed by mid-October. Several changes in the C1 contents have been implemented, including increased cloud top pressure categories and revised error categories. A few more changes in the diagnostic step that produces the C1 data must await completion of the revisions of the detection and radiative analysis steps.

The C1 data set for January 1984, obtained using the "old" algorithm, has been sent to the ICA. Inspection of the results for winter conditions and without the snow and ice data shows very encouraging results. There were no new problems; some difficulties with the snow and ice cover are apparent, but the planned algorithm revisions should eliminate most of these. Indeed, the clear sky reflectances and temperatures obtained were consistent with relatively accurate snow and sea ice line positions.

ISCCP Central Archive (ICA):

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

The health of GMS-3, METEOSAT-2, GOES-6, GOES-7, NOAA-9 and NOAA-10 remained good. Launch of NOAA-H has been delayed to no earlier than February 18, 1988 to allow installation of an improved version of the SBUV instrument. This delay was decided since a new TOVS processing procedure has been implemented at NOAA that can get around the lack of MSU data from NOAA-9. With successful launch of Ariane this past month, the launch of the replacement METEOSAT is now planned for early 1988.

OTHER ITEMS

W. Rossow attended the meeting of the CAS/JSC Working Group on Numerical Experimentation last month to brief the members on the characteristics of C1/C2 data and to advise them on the status of data set production. The WGNE is planning a comparison of GCM's with each other and with ISCCP and ERBE data sets. The primary focus is on forecast GCM's that can be run from initial conditions. Two issues had been raised by the WGNE: some early concern about the C1 data format and a concern about the timely availability of data. The briefing eliminated both of these concerns. Apparently the concerns about the data format were based on misleading impressions obtained from the early pilot data sets, rather than actual C1 data. The WGNE did not recommend any change in the C1/C2 format. A thorough discussion of the C1 data contents, their interpretation, and examples of model/data comparisons conducted at the GPC led the WGNE to revise their project plans to have two phases: a learning phase utilizing the July 1983 C1 data that they already have and a second phase to be conducted when the ISCCP and ERBE data sets for April 1985 become available early next year. The first phase will include a preliminary comparison of the models and ISCCP data, utilizing very simple cloud parameters, while the participants work on the development of new model diagnostics that can exploit more of the contents of the ISCCP data and that can combine the ISCCP and ERBE information effectively.

Delivery of replacement NOAA-8 B2 data for October 1983.

Revision of the IR count translation tables for GOES satellites.

Delivery of BC data for GOES-6 for January 1984 through July 1984 and for January 1985 and January 1986.

Delivery of GMS B3 data for August 1983 through January 1985.

Delivery of NOAA-8 B3 data for October 1983 through June 1984.

Delivery of B3 data for 1985 and 1986.

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

Arranging for the delivery of INSAT B1 data.

Beginning the delivery of the correlative data sets.

Completing final revisions to the cloud algorithm.