Effects of Large-scale Modes of Atmospheric Circulation on the Regimes of Temperature and Precipitation in the Arctic

The monthly and seasonal anomalies of temperature and precipitation over the Arctic are considered depending on the global and regional patterns of atmospheric circulation. Alimate indices are used to identify patterns. The composite analysis allowed identifying the geographic regions where the influence of atmospheric circulation modes on temperature and precipitation is statistically significant. The contingency of atmospheric circulation patterns in the Northern Hemisphere was statistically estimated. Special attention is paid to the case studies where the extreme episodes of circulation indices are associated with the significant anomalies of air temperature and precipitation. The potential is demonstrated of the numerical simulation of extreme episodes on monthly and seasonal timescales with the global semi-Lagrangian model SL-AV developed in the Institute of Numerical Mathematics jointly with the Hydrometcenter of Russia.