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. Keywords: Precipitation, The assiniboine river basin, The Northern Great Plains, CaPA, ERA-interim, ERA5, JRA-55, MERRA-2, NLDAS-2