Quality of Snow Cover Characteristics Derived from ERA5-Land Reanalysis for Perm Krai

The agreement between values of the mean monthly snow depth provided by the ERA5-Land reanalysis and similar characteristics of snow cover calculated on the basis of the extended hydrometeorological monitoring performed in Perm krai for 1990–2020 has been analyzed. It has been found that ERA5-Land in 73% of cases reproduces the presence and absence of snow during the onset period and in 53% of cases during the period of snow loss. The conclusions made in the authors’ previous studies based on more limited material have been generally confirmed. It has been shown that the reanalysis values of the snow depth have been overestimated in relation to instrumental measurements for most of the hydrometeorological stations of Perm krai. In space, the magnitude of the reanalysis error has increased from the southwest to the northeast of the region, with the exception of its central part, where the influence of the Kama water reservoir is perceptible. However, the interannual variability of the average snow depth in Perm krai has been reproduced by the ERA5-Land reanalysis adequately. For 30 years, the magnitude of the reanalysis error decreased as it was compared with 61% observation points. The analysis of seasonal variability has shown that in ERA5-Land, the time of the maximal snow depth was shifted to an earlier onset. The complete coincidence of the seasonal course has been recorded only in 5% of hydrometeorological monitoring sites. The value of the average monthly discrepancies between the data of the reanalysis and the information of the posts as a whole has exceeded the similar characteristic for the stations, which has been especially evident during the period of active snowmelt.