Fusing precipitation for NOAA's AWIPS DSS through a hydro-information system

Accurate precipitation estimation is essential to hydrologic modeling for flood and drought forecasts. With advancements in technology, precipitation can now be measured by a range of sensors, including the NOAA/National Weather Service NEXRAD radar network, satellites, and rain gauges. Each measurement platform and the data product(s) associated with it have their own strengths and weaknesses. There are different precipitation products derived from different data sources and from combinations of them. These data products vary in their spatial and temporal resolutions. In this study, we illustrate the integration of our MKF-based (Multiscale Kalman Filter) framework with our hydro-information system to fuse Stage III/Multi- sensor Precipitation Estimator (MPE) hourly NEXRAD precipitation data at approximately 4 by 4 square kilometer resolution with the precipitation data from LDAS (Land Data Assimilation Systems) at 1/8 degree resolution. Two data products from LDAS are investigated. One is the EDAS (NCEP's Eta-based 4-D Data Assimilation System) precipitation product, and the other is the combo precipitation product which is derived from the ?degree CPC (Climate Precipitation Center) daily precipitation data from rain gauges. The combo product is interpolated to 1/8 degree resolution based on the budget bilinear interpolation method. The daily time step of the combo product is disaggregated into hourly data based on either the weight of the hourly Stage II NEXRAD radar or EDAS hourly precipitation or uniformly, if there is no information from either Stage II NEXRAD radar or EDAS hourly precipitation. Our hydro-information system facilitates heterogeneous data retrieval from different data sources into the MKF-based data fusion framework, and then to the hydrological modeling system through an extension of the Hydrological Integrated Data Environment (HIDE) system. Initial results show significant differences in spatial coverage and magnitudes between the original LDAS precipitation data products and the fused precipitation at 1/8 degree resolution. Impacts of the fused precipitation on hydrologic simulations and on flood and drought forecasts will be investigated.