SR SSD 99-29
12-1-99

Technical Attachment

Summary and Comments from 1999 GOES Assessment Meeting

Ken Waters
Scientific Services Division

During the first week of November I attended the 1999 GOES Assessment Meeting in Boulder, Colorado. Some of what I consider to be significant results from this meeting are summarized below. In addition, on Friday of the same week there was a special meeting to discuss GOES sounder sectoring strategy. Information from that meeting also follows.

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GOES Assessment Meeting

The one common theme heard many times throughout the entire meeting was the need to get GOES sounder and Derived Product Imagery (DPI) data onto AWIPS so forecasters at more field offices can view the data. Western Region has been doing this using the GOES-W data. Additionally, CIMSS (University of Wisconsin) has been producing DPI using GOES-E data. I am now working with CIMSS to get this imagery into our SRH AWIPS so it can be further distributed within the region. I know this is desirable for offices within the region, so I will keep everyone advised of progress.

Timing of the two GOES Assessment tests carried out this year was not good. Both tests missed the severe weather season. The Auto-Estimator test had few inputs due to its schedule (September 1 to October 15) and the relatively quiet weather patterns which prevailed nationwide. (The sole exception being hurricanes along the East Coast.)

NESDIS and NWS are pushing strongly to get some case studies showing use of sounder data and/or DPI. Emphasis is on studies which show (1) operational impact and value of the data, and (2) direct comparisons with model output data. Studies combining both of these elements are very valuable and useful for defending the GOES sounder program. (WFO Birmingham forecaster Tom Bradshaw has pointed out that studies need to be undertaken which directly compare the accuracy/utility of DPI convective fields vs. those fields produced by mesoscale data assimilation and forecast systems (e.g., ETA, MSAS/RUC, MM5, ARPS). As Tom says, "I'm a big advocate of satellite imagery as an analysis tool ... [but] I'm also becoming a BIG advocate of the model-based analysis and forecast tools I now have at my disposal on AWIPS.")

It's incumbent on the satellite proponents to demonstrate the worth of DPI products relative to the other analysis tools presently available. One presentation at the meeting compared Eta model soundings with the GOES soundings, showing the latter (GOES) to be much better at picking up moisture bands. Field offices can help with more such studies through collaborative projects.

The most useful DPIs at field offices were CAPE, CINH, lifted index, K-index, and TPW (total precipitable water). Another parameter, CTP (cloud top pressure), had difficulty determining tops of low-level clouds. Others, such as skin temperature, were found to be of little use at the WFOs.

NESDIS will shortly unveil a new Web page which is supposed to tell you "everything you ever wanted to know" about the satellite program (both POES and GOES), including a thorough background on how the signals are processed, what is in the data stream, details about the imager and sounder channels, and so on. NESDIS expects this Web site to be online before the end of the year.

The satellite precipitation Auto-Estimator will be implemented, along with the IFFA (Integrated Flash Flood Analyzer), which requires manual operator input. Once again, though, the key will be to have these data available on AWIPS.

Sounder Scanning Schedule Meeting

Current scanning schedules and sector sizes were discussed.

The following changes were agreed to by the participants at the meeting:

For GOES-E, one scan line will be sliced off the top of the sector (mostly scans over Canada) and will be added to the south edge of the sector; this should be able to pick up Key West, which was previously left out. The overlap between the CONUS and Gulf sectors will be reduced, and moved to extend the Gulf sector a little further west. It currently stops just west of the Gulf of Mexico coastline. The scanning schedule will be changed; currently the CONUS sector runs once per hour, followed by the North Atlantic (every 6 hr), South Atlantic (every 6 hr), and Gulf (every hr). It was agreed to drop the North Atlantic sector completely from the schedule, pending concurrence from NCEP's Marine Prediction Center, with the exception of during the hurricane season.

For GOES-W, the North Pacific sector will be reshaped to go farther north, and not so far out to the west. The Baja sector will be stretched to the east (this should be of interest to Albuquerque and El Paso).