ИСТИНА

Detailed long-term hydrometeorological dataset for Russian Arctic seas was created in 2020 using long-term COSMO-CLM hydrodynamic modelling for 1980 – 2016 period with ~12 km grid size. Many test experiments and its verification revealed the best model configuration. An optimal model setup included usage of ERA-Interim reanalysis as forcing data, 5.05 model version with a so-called ICON-based physics and spectral nudging technique. Final long-term experiments were simulated on the MSU Supercomputer Complex “Lomonosov-2” and become more than 120 Tb data volume. The Russian Arctic COSMO-CLM hindcast has 1-hour output step, contains approximately a hundred hydrometeorological characteristics, as well at surface, as on the 50 model levels. Primary evaluation of obtained dataset was done for surface wind and temperature compared with ERA-Interim forcing data. There are some mesoscale details in wind speed climatology reproduced by COSMO-CLM dataset including the Svalbard, Severnaya Zemlya islands, and the western coast of the Novaya Zemlya island. At the same time, high wind speed frequencies based on COSMO-CLM data increased compared to ERA-Interim, especially over Barents Sea, Arctic islands (Novaya Zemlya) and some seacoasts and mainland areas. Significant regional details in temperature patterns manifested in relief and lakes, e.g., over Scandinavian mountains, Eastern Siberian and Taymyr highlands, Novaya Zemlya ranges. The added value in the 1% temperature percentile patterns is more pronounced, especially in the mountainous Eastern Siberia. Model capability to reproduce strong downslope windstorms evaluated according to the observations timeseries over Novaya Zemlya, Svalbard and Tiksi stations during bora conditions. Generally, the ASRv2 and COSMO-CLM reproduced the wind direction equally close to observations, and the wind speed is worser according to the ASRv2. The extreme wind speed frequencies during bora cases have less errors according to COSMO-CLM hindcast (up to ~5%) compared to the ASRv2 data (up to 10%). At the same time, moderate wind speed frequencies are reproduced by ASRv2 better. Russian Arctic COSMO-CLM hindcast 2m temperature evaluation according to the long-term monthly station data (more than 100 stations) has shown model is quiet underestimating surface temperature. The reason could be due to contribution of the Eastern Siberian mountainous regions and errors in the model surface height. 37-year period and a large Arctic region covered by dataset required a lot of memory. This would be a certain technical issue to share all these data using any host, HTTP or FTP services. At the first stage, we have prepared a subset that included 7 main surface variables within the entire period and uploaded it to the Figshare service (https://doi.org/10.6084/m9.figshare.c.5186714).