Wednesday, 16 January 2002: 3:45 PM
Status and Outlook of Operational Satellite Precipitation Algorithms for Extreme Precipitation Events
This paper describes the status and outlook for operational satellite precipitation algorithms for extreme precipitation events. Many algorithms have been developed over the years (WMO, 1999 and Barrett and Martin, 1981) for estimating precipitation on all scales ranging from the storm/mesoscale to the synoptic and climate/global scales. These algorithms are based on infrared and visible data from geostationary satellites or microwave data from Polar Orbiting Environmental Satellites (POES). This discussion will concentrate on the precipitation efforts taking place in the National Oceanic and Atmospheric Administration (NOAA), National Environmental Satellite, Data, and Information Service (NESDIS): past, present and future. For most of the past 20 years, the production of Satellite Precipitation Estimates (SPE) and outlooks for flash floods has been a manual/interactive process for alerting forecasters and hydrologists of the potential for heavy precipitation and flash floods. These SPE have been generated operationally since 1978 using the Interactive Flash Flood Analyzer (IFFA). Precipitation estimates for flash floods are Geostationary Operational Environmental Satellite (GOES)- driven products due to the high spatial and time resolution characteristics of GOES. Recently, the challenge has been to automate SPE for flash flood and other applications. Automation will allow an increase in the use of SPE from being merely an "alert tool" to infusion into the National Weather Service (NWS)/Office of Hydrology Stage III Product (gauge + WSR 88D + satellite), into hydrological flow models that are run at local River Forecast Centers (RFCs), into numerical weather prediction models for improved Quantitative Precipitation Forecasts (QPF), and into cloud models (that will in turn provide precipitation estimates). NESDIS has implemented several algorithms (developed both within and outside NESDIS) for comparison and validation. Collaborative efforts have been initiated with: (1) the NWS West Gulf River Forecast Center (RFC) for the development of integrated precipitation data sets along with the use of GIS (Geographic Information System)data sets that will improve the production of stream/river flow and crest forecasts, (2)the National Centers for Environmental Prediction (NCEP)/Environmental Modeling Center for ETA model initialization over remote areas such as oceans, (3) the Cooperative Institute for Research in the Atmosphere (CIRA) at Colorado State University for cloud modeling studies and (4)the NCEP/Tropical Prediction Center for testing an algorithm for predicting hurricane rainfall (called TRaP=Tropical Rainfall Prediction). The future of satellite rainfall algorithms for extreme precipitation events is exciting. More accurate and robust precipitation algorithms for extreme precipitation events will become operational in the near future. These improved algorithms will make use of the many current and planned GOES channels (such as GOES-R in the 2010 time frame) combined with the more physical microwave data from the SSM/I (Special Sensor Microwave Imager), AMSU (Advanced Microwave Sounding Unit), TRMM (Tropical Rainfall Measuring Mission), and AMSR (Advanced Microwave Scanning Radiometer). Our greatest hope is to have the Global Precipitation Mission (GPM) in operations by the 2007 - 2010 time frame where geostationary infrared data will be frequently calibrated by microwave data onboard the GPM fleet of satellites. As we go world-wide with our satellite rainfall algorithms for extreme events, the potential benefits to the user community will be immense.