Summer precipitation variability in the Mongolian Plateau and its possible causes

The climate and ecosystem in the arid and semi-arid regions including the Mongolian Plateau (MP) are fragile and vulnerable to the changes of precipitation. This study investigates the summer precipitation variability in MP during 1979-2021. Results show that the leading mode of summer precipitation variation in MP is characterized by a same-sign pattern, with pronounced interannual and interdecadal fluctuations. Further analysis indicates that this leading mode is affected by both internal atmospheric circulation and remote oceanic forcing. A new internal atmospheric teleconnection pattern propagating from North Europe to Polar and East Asia (NPE) is identified as a key circulation factor of the summer precipitation variability in MP. The anomalous ascending motion and water vapor convergence associated with an anomalous cyclone of the NPE pattern facilitates the increase of precipitation in MP. Besides, a dipole surface sea temperature anomaly pattern in the North Atlantic may excite a zonal wave train propagating eastwards toward Mongolia and increase the precipitation in MP. Sensitivity experiments confirm the impact of the North Atlantic dipole SST anomalies on the precipitation variability in MP. Quantitative analysis indicates that the internal atmospheric NPE teleconnection accounts for approximately 21% of total variance of summer precipitation in MP, and the North Atlantic oceanic forcing is relatively weak, explaining about 10% of precipitation variation in MP.

Automated summary

This study investigates the summer precipitation variability in the Mongolian Plateau during 1979-2021. The results show that the leading mode of summer precipitation variation in the Mongolian Plateau is influenced by both internal atmospheric circulation and remote oceanic forcing. The study also identifies a new internal atmospheric teleconnection pattern and a dipole surface sea temperature anomaly pattern in the North Atlantic that have impacts on the precipitation variability in the region.