Examination of the Spatial Correlation Among Gauge Precipitation Data and Gridded Radar Data for the Determination of Sufficient in-Situ Network Coverage

Abstract:

Many climatic studies, including the recently released third National Climate Assessment report, rely heavily on in-situ rain gauge data. Sufficient rain gauge coverage is necessary for the accurate cataloging of precipitation data used in assessing climatic trends, as well as the study of extreme events on a more localized level. Understanding how representative an in-situ gauge is of its surrounding area is imperative in determining adequate network coverage. Factors such as topography and seasonal influences play a vital role in the spatial variability of precipitation, impacting our ability to interpolate data between point measurements. The nearly universal coverage of radar offers a high-resolution approach to the analysis of areas between in-situ rain gauges.

The spatial correlation among GHCN (Global Historical Climatology Network)-Daily gauge precipitation data and Stage IV gridded radar data is examined. Multiple regions of the United States with varying topography are analyzed seasonally in order to observe the effects these features have on correlation of precipitation. Correlation as a function of distance is evaluated to determine rate of decay in these regions.