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University of California at San Diego: Integration of Optical Line Scanner (OLS) and Special Sensor Microwave Imager (SSM/I) data into operational weather forecasting

Final Report

Since the mid-1970's satellite data have played an ever-increasing role in operational weather forecasting. Data from both geostationary (e.g., GOES) and polar orbiting satellites have been used to monitor storms, as input to forecasting models, and to monitor El Nino Southern Oscillation events. Unfortunately, orbit considerations preclude the use of GOES data at high latitudes such as those served by the NWS Alaskan Region. Moreover, the recent failure of the NOAA-13 satellite, coupled with the projected useful lifetimes and overlapping orbits of currently flying polar-orbiters, limits the amount of visible and infrared satellite data available for forecasting purposes in the Alaskan region.

The Defense Meteorological Satellite Program (DMSP) is a second-generation polar-orbiting satellite developed to support operations of the Department of Defense. All DMSP satellites have carried the Operational Linescan System (OLS) which is designed to gather data in the visible and infrared spectral regions. In 1987, the Special Sensor Microwave Imager (SSM/I) was added to the DMSP suite of sensors. This is a passive microwave radiometer, which detects thermal energy emitted and reflected by the Earth's atmosphere in the microwave portion of the electromagnetic spectrum. SSM/I data can be used, for example, to measure ice coverage, areal extent and intensity of precipitation, cloud water content, and land surface moisture. However, because DMSP was a classified program until recently, relatively little use of DMSP data has occurred in either civilian or educational applications. Moreover, many of the basic features of the DMSP satellite and data are not well known by the unclassified community.

The objectives of this project were to:

For the university, the major benefits from this project were the ability to access fine scale OLS data and ground-truth data (e.g., ice) for validation of algorithms. For the operational forecasters, the researchers' design for ingest and manipulation of the DMSP data was incorporated into the AWS/NWS wide area network being implemented by Elemendorf Air Force Base. This base is the only AWS site that has the requirement to support other DoD sites directly. Both DMSP and NOAA polar data (supplied by NWS HIPS) will flow on the wide area system. This has provided both an increase in spatial and temporal resolution, as well as unique data sets. The principal investigator also provided important guidance and consultation on the use of cloud discrimination algorithms and their use with polar imagery. This information is being used for a program to determine clouds above ASOS systems that only measure to 12,000 feet.