Future Research and Application Needs of Radar Rainfall Data in Hydrology

The hallmark of recent advances in radar precipitation estimates is the high resolution detection of spatially variable rainfall over large areas. Radar data far exceeds spatial densities of most rain gage networks and is useful for filling in the gaps between gage measurements. While radar provides the spatial and temporal patterns of rainfall, it requires correction or adjustment to remove systematic over- or underestimation of rainfall rates. Research in radar measurement of rainfall is needed to address the accurate conversion of reflectivity to rain rate, how radar system characteristics affect resolution and precision of the rainfall data, and improved methods for bias adjustment to remove systematic errors. First, we examine the origin and characteristics of radar estimation of rainfall, implementation of radar technology and algorithms, and then provide an overview of radar research needs in hydrology. Research and resulting advances in radar hardware and computer algorithms are expected to improve the use and reliability of radar information for civil infrastructure design and flood forecasting operations.