The Potential of INM-CM5 Multi-year Climate Forecasts for Hydrological Application in Russian River Basins

This study assesses the potential of the INM-CM5 climate model to provide multi-year (1–5 years) forecasts of monthly and average annual precipitation and surface air temperature for hydrological application across Russia. Retrospective forecasts (hindcasts) for the period from 1991 to 2023 were used. The forecasts were verified for 12 river basins located almost throughout the entire territory of Russia. To eliminate systematic errors in forecasts, a method for their correction has been proposed, which allows reducing the error of ultra-long-term precipitation and air temperature forecasts by almost two and three times, respectively. The forecasts of intra-annual precipitation distribution turned out to be satisfactory for 8 river basins out of 12. The forecasts of intra-annual air temperature distribution turned out to be good for all 12 river basins. In general, the INM-CM5 climate model demonstrates the potential of using long-range forecasts of monthly and annual precipitation, average monthly and average annual air temperature, particularly after statistical post-processing, for extended hydrological predictions in Russian river basins.