NUMBER 51
DATE: 11/02/87
Sector Processing Center (SPC):
During September, CSU, ESA and JMA collectively processed greater than 93% of A data into B1 and/or B2 data. AES processed 72% of the A data into B1/B2. No processing matrix was received from NOAA for September.
Normal operations were reported by CSU, ESA, JMA and NOA.
AES reported data losses on 12-13 September caused by a complete power outage and on 25-26 September caused by receiving equipment malfunction. The 4 pixel offset of the VIS images, reported previously, was caused by a software error, which was corrected for the processing of the September B2 data.
JMA reported completion of the corrected AC data for March 1987 through September 1987; these data will be sent to the SCC this month.
Monthly reports for July, August and September were received from CSU. They reported more details of the NOAA procedure to save the GOES-6 encoder lamp and avoid scanner sticking. The original plan to image only part of the Earth was modified to obtain a complete image every three hours to avoid lubricant build-up; from day-of-year 190 to 194, images were collected only once per hour at 15 minutes past the hour to recover performance. GOES-6 was in eclipse during September; the 0745 GMT image replaced the 0845 GNT image during this period.
The representatives from CSU, UWS and the GPC met to determine a new translation table to convert the
new AAA format GOES 10-bit IR data into 8-bit data for ISCCP. They decided to take advantage of the extra
resolution to produce a count scale that is linear in radiance, making the GOES data like all the other IR data.
The temperature resolution will be approximately that of the NOAA translation tables, namely, about 0.3 K at
temperatures of about 300 K and about 1 K at temperatures of about 240 K. Currently, the AAA format GOES
data are being translated by simulating the old count scale.
Special Area Processing Center (SAPC):
No reports were received.
Satellite Calibration Center (SCC):
BC results for GOES-6 were received from the SCC for January and April 1984 and July and October 1986.
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.
NOAA-9 B3 production got off to a rugged start because of the irregular amount of data for January and February 1985 and because of a change in tape format in May 1985 from 1600 bpi to 6250 bpi. Since the overlapping data for NOAA-7 and NOAA-9 is crucial to the calibration of the whole ISCCP data set, we have produced B3 data for both satellites for January and February 1985 to be archived. Production of NOAA-9 B3 has been completed through June 1985; this production run will go through January 1986 within the next two weeks. Inspection of the monitor results, which is underway, must be completed before delivery of the data to the ICA.
The QC backlog for 19 months of GOES-6 data has been eliminated. Final inspection of some additional suspicious images will be completed in the next two weeks and a complete report written. The first steps of the QC are now included in CLIPS; inspection of the NOAA-9 B3 will begin in later this month.
With the receipt of BC data for January and April 1984, the GOES-6 B3 data will be re-copied to add the BC information. The GOES-6 B3 for November 1983 through April 1984 will then be delivered to the ICA later this month.
Final optimization of the GMS navigation code is complete. Production of the GMS B3 data will begin as soon as the NOAA-9 production is completed. This production run will continue through January 1985.
NOAA-8 B3 production will commence after the completion of the GMS B3 production. The entire B3 data set through January 1985 should then be completed and archived by the end of this year.
Remapping of the snow data for 1983 and 1984 has begun. Once these data sets are completed, they will be merged with the sea ice data to produce the final product. Documentation and a tape format have been designed; these data should be archived at the ICA by the end of November.
The revised TOVS production code has been completed. Comparisons between the TOVS climatology and that of Oort are underway to determine whether the Oort climatology can be used to fill gaps in the TOVS data. Tests of the accuracy of extrapolation of TOVS observations in time and space indicate that errors are of the same order as the stated accuracy of the TOVS analysis (i.e., 2 - 3 K) for replication from one 2.5 degree grid cell to an adjacent cell. (This procedure will be modified to check for large topography changes before replication.) Somewhat larger errors are produced by replication from two cells away or from an adjacent day. Comparisons with the Oort climatology will be used to test the final filling scheme. Production of TOVS data in the final format should begin within a couple of weeks; first delivery of these data to the ICA should occur in December.
All adjustments to the new clear sky code in the cloud detection portion of the algorithm have been completed. The improved treatment of the VIS clear sky has been implemented and tested. A set of universal tables have been installed to convert counts to physical quantities and back again. The non-linear IR threshold has been implemented, producing improved (more conservative) polar results. This threshold, together with the correction for the use of the maximum temperature under some circumstances (as described at WGDM 6 in Colorado), has also eliminated the spurious detections at low latitudes. Additional QC tests have also been installed that have eliminated most of the bad data contaminating the clear radiances. Test runs are underway to re-tune the algorithm to be consistent with the previous results and the estimated uncertainties in the clear radiances.
Most of the minor revisions to the radiation code have been completed; however, some additional adjustments
to the new TOVS format are being made. Additional tests of the TAU correction procedure are planned for
late November. 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.
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. The third
encoder lamp on GOES-6 failed on 5 October 1987; GOES-6 is now operating on its last encoder lamp. Past
experience suggests that this lamp will not last more than 12 - 18 months; hence, GOES-6 data will probably
cease late next year or early in 1989. Delays in the fabrication of instruments and delivery of new launch
vehicles for the next series of GOES satellites appear to preclude a launch of a replacement for GOES-6 any
earlier than spring of 1990.
A major workshop, sponsored by WCRP, NASA, NOAA, NSF, and DOE and titled "Clouds in Climate II", was
held in Columbia, Maryland during the week of 19 October 1987. The presentations indicate that much
interesting research is beginning, involving comparisons of models and data, comparisons of data from
different platforms as part of the Regional Experiments, and studies of cloud model (radiative, physical)
improvements. The workshop provided an early opportunity to compare global results from ISCCP,
NIMBUS-7, Warren/Hahn/London, and ERBE. A personal impression was that these results show that we
are beginning to converge on the same answer, once account is taken of the differences in analysis methods
and observations systems. Preliminary plans were made for intercomparisons to be made with these data sets
during the coming year. The coming year will also see very interesting studies based on the data obtained
from FIRE and ICE.More data will also be collected by ICE and NWPCRE in the next two or three years.
Delivery of BC data for GOES-6 for July 1984, 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.