Assessment of the capability of modern reanalyses to simulate precipitation in warm months using adjusted radar precipitation

Study region: Central Europe Study focus: Precipitation fields from reanalyses have been widely used for hydrological applications, meteorological extreme analyses or climatological research. Modern reanalyses provide all characteristics in regular grids with high resolutions and thus can substitute for gridded in situ, radar and satellite observations. Here, we assess the ability of three modern reanalyses with different spatial resolutions and different rates of assimilation to reproduce precipitation in Central Europe. Two global (ERA-5 and ERA-5 Land) and one regional (Mescan-Surfex) reanalysis products are evaluated against adjusted radar-derived precipitation totals in the warm parts of the 17-year period. New hydrological insights for the region: A comparison of daily precipitation totals generally shows good agreement with the observations in all reanalyses. However, the detailed analysis of climatological indices shows a general overestimation of precipitation sums and the number of wet days in all tested months but an underestimation of high precipitation on monthly or seasonal sums and a lower occurrence of days with sums above 10 mm. Mescan-Surfex seems to be the most accurate of all three reanalyses, with the exception of the years between 2009 and 2012, with very low precipitation in southern Bohemia. The largest differences between radar and reanalysis precipitation characteristics are detected in the summer months when convective precipitation prevails. The obtained results can be used for further applications in hydrological modelling.

Automated summary

This study evaluates the ability of three modern reanalyzes with different spatial resolutions and assimilation rates to reproduce precipitation in Central Europe. The results show that all reanalyzes generally agree well with the observations in terms of daily precipitation totals. However, a detailed analysis of climatological indices reveals an overestimation of precipitation sums and the number of wet days, as well as an underestimation of high precipitation on monthly or seasonal scales. Mescan-Surfex seems to be the most accurate reanalysis, except for the years with low precipitation in southern Bohemia. The largest differences between radar and reanalysis precipitation characteristics are found in the summer months. These findings can be used for further hydrological modeling applications.