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ON THE USE OF NEXRAD STAGE IV DATA IN THE MULTIMEDIA MODELING OF POLLUTANT TRANSPORT
Citation:
Eder, B K., S K. LeDuc, A B. Gilliland, AND P L. Finkelstein. ON THE USE OF NEXRAD STAGE IV DATA IN THE MULTIMEDIA MODELING OF POLLUTANT TRANSPORT. Presented at Symposium on Precipitation Extremes: Prediction, Impacts, and Responses, Boston, MA, January 14-19, 2001.
Impact/Purpose:
This task has the following objectives:
Improve modelers' ability to focus on scientific and policy issues in modeling studies by providing software that supports composing, applying, and evaluating complex systems of models.
Improve the understanding of the interaction of the atmosphere and the underlying surface, especially the flux of mass in both directions, and EPA's ability to simulate that interaction.
Contribute to multimedia studies and assessments by applying state-of-the-art atmospheric models, estimating atmospheric contributions to multimedia issues and the sources of those contributions, and evaluating the models' strengths and weaknesses.
Description:
The Environmental Protection Agency (EPA) is designing the Multimedia Integrated Modeling System (MIMS) to model the cycling of pollutants and nutrients between the atmosphere and the earth's surface, including water bodies and groundwater. Our ability to accurately model both atmospheric, hydrological and surface processes that transport chemicals is highly dependent on precipitation types, rates and totals. Of special interest are precipitation extremes and subsequent flooding, which can greatly enhance the movement of such chemicals. During such events, these chemicals can enter the surface water bodies via groundwater recharged as well as overland flow. For example, the extreme flooding associated with Hurricane Floyd, which made landfall in North Carolina during September of 1999, transported tremendous amounts of agricultural and industrial waste and pesticides into area estuaries and rivers. This hurricane, which made landfall shortly after an earlier hurricane, Dennis, inundated sections of eastern North Carolina with more than 20 inches of rain. During the development of MIMS, we are investigating the use of the National Weather Service NEXRAD (NEXt generation RADar) Stage IV precipitation estimates in our modeling efforts. The NEXRAD Stage IV data consists of precipitation data fields that have assimilated both rain gage data and WSR-88D (Weather Surveillance Radar 1988 Doppler Version) data into a comprehensive hourly, national data set with a 4-km2 resolution. The purpose of this research is to evaluate the quality and identify limitations of the NEXRAD data through a comparison with "ground truth" data obtained from a network of ten closely spaced rain gages. The evaluation, which will use visualization tools and statistical analyses will determine if the spatial resolution of NEXRAD data is adequate to capture the spatial variability of precipitation on the watershed that is used in the surface hydrology models associated with MIMS.