Impact of Spring Barents Sea Ice on Summer Tibetan Plateau Precipitation

The spring (April–May–June) Barents Sea ice has been proven to affect the summer surface air temperature over the Tibetan Plateau (TP). However, its impact on summer (June–July–August) TP precipitation, a crucial climate component, remains unexplored. We investigate the physical linkage between spring Barents Sea ice and subsequent summer TP precipitation from 1979 to 2018. Our results indicate that above-normal spring Barents Sea ice leads to excessive summer TP precipitation, and vice versa. During spring, more Barents Sea ice induces remarkable cooling and subsidence over there and surrounding areas. The cooling over the Barents Sea can persist into summer, triggering a meridional wave-like pattern along the longitude of 60°E and, in turn, an anomalous atmospheric subsidence over the Caspian Sea and the eastern region adjacent to it. This alters 200 hPa convergence and modulates the Silk Road pattern (SRP). As a result, cyclonic anomalies form to the west of the TP, which enhance moisture transport toward the TP and increase its precipitation during summer. Numerical experiments reproduce these physical processes and further support our conclusions.

Key words: Barents Sea ice, Tibetan Plateau precipitation, Silk Road pattern, numerical experiment