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United States Department of Agriculture

Agricultural Research Service

Title: Sub-Pixel Rainfall Variability and the Implications for Uncertainties in Radar Rainfall Estimates

item Zhang, Yu - USEPA-NRMRL

Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: September 6, 2005
Publication Date: December 5, 2005
Citation: Zhang, Y., Adams, T.E., Bonta, J.V. 2005. Sub-pixel rainfall variability and the implications for uncertainties in radar rainfall estimates [abstract]. American Geophysical Union 2005 Fall Meeting.

Technical Abstract: Radar estimates of rainfall are subject to significant measurement uncertainty. Typically, uncertainties are measured by the discrepancies between area rainfall estimates based on radar reflectivity and point rainfall records of rain gauges. This study investigates how the discrepancies can potentially arise owing to the intrinsically different spatial scales of the two sets of measurements. Gauge-radar comparisons are made between observations from a network of 11 rain gauges, which are clustered within a 3km radius at the USDA North Appalachian Experimental Watershed near Coshocton, OH, and corresponding NEXRAD Stage III rainfall data collected by the NWS Ohio River Forecast Center. The methodology of error separation was employed both with and without considering small-scale spatial correlation, to examine the sensitivity of estimated impacts of area-point difference to different conceptualizations of the spatial rainfall structure. The dependence of the outcome of the approach on the climatology of precipitation systems is further assessed through comparative examination of the rainfall records during the July and October of 2001. The implications for how to account for uncertainties when applying radar rainfall estimates to field scale and watershed scale analysis are discussed based on the findings.

Last Modified: 4/22/2015
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