Evaluation of variability among different precipitation products in the Northern Great Plains

Abstract

Study region The Northern Great Plains. Study focus Seasonal and extreme hydro-climatological events in the Northern Great Plains can have significant socio-economic impacts. Although a variety of precipitation datasets can be used for characterizing the hydro-climatological behavior of this region, much of our knowledge on precipitation variability among different products over this region comes from the coarse-scale evaluation studies for the whole Canada or CONUS, many of which may under-represent the performance of different precipitation products over these areas. The present study is intended to fill this gap. Daily total precipitation data derived from CaPA, ERA-Interim, ERA5, JRA-55, MERRA-2 and NLDAS-2, respectively, are evaluated over the Assiniboine River Basin (ARB), which represents many of the hydro-climatological complexities associated with the Northern Great Plains. Additionally, the spatial and year-to-year variations in total liquid water flux for spring and early summer are also examined over the ARB. New hydrological insights for the region Precipitation products typically perform better in spring and autumn than in summer and winter. Overall, CaPA performs best, except for a severe underestimation of summer precipitation. MERRA-2 is typically the second best. ERA5 typically outperforms ERA-Interim. NLDAS-2 has a fairly low performance. JRA-55 has the lowest performance, exhibiting a strong wet bias. The quantified variability among these products will help characterize sources of uncertainty for hydro-climatological analysis within the Northern Great Plains.