The Cooling Over Northeast Asia in June Over the Most Recent Decade: A Possible Response to Declining Bering Sea Sea Ice in March.

In sharp contrast to rapid global warming, the surface air temperature (SAT) in Northeast Asia (NEA) has exhibited strong cooling in June since 2010. Our results show that this cooling is a possible response to declining Bering Sea sea ice concentrations (BSICs) in March. A physical process analysis shows that decreasing BSICs provoke a south‐eastward‐propagating Rossby wave train and induce a strong anomalous anticyclone over the midlatitude Northwest Atlantic, resulting in tripolar anomalous sea surface temperature (SST) pattern with warm anomalies in the midlatitude Northwest Atlantic. These persistent tripolar SST anomalies generate a new Rossby wave across Eurasia in June, which enhances the cyclonic atmosphere circulation anomaly over NEA and leads to the cold SAT anomalies observed in this area. Correspondingly, in response to the sharp decline in BSIC in March, the NEA has exhibited an unprecedented cooling trend in June over the most recent decade. Plain Language Summary: In contrast to rapid global warming, the surface air temperature (SAT) over Northeast Asia (NEA) in June has exhibited a strong cooling trend since 2010, which has had an important impact on local agriculture. Here we show that reduced Bering Sea sea ice concentrations (BSICs) in March promote cold SATs in the following June in NEA. Declining BSICs in March excite a Rossby wave train that propagates eastward, causing a strong anomalous anticyclone (cyclone) over the midlatitude North Atlantic (subpolar Atlantic) and a tripolar anomalous sea surface temperature (SST) pattern by modifying the surface heat flux. The tripolar SST pattern in the North Atlantic develops in April and May due to the downstream development of the wave train; it persists in June mainly due to the ocean memory effect and subsequently generates a new Rossby wave across Eurasia via eddy‐mediated processes, provoking a cyclonic atmospheric circulation anomaly over NEA and leading to the observed cold SAT anomalies. Accompanying the significant BSIC decline in March since 2010, the atmospheric regime and SST variations over the North Atlantic in association with the cold SAT anomalies observed in NEA in June have strengthened and thus induced strong cooling over NEA. Key Points: Unusual cooling has been observed in June over Northeast Asia (NEA) under the most recent global warmingThis June cooling in NEA is consistent with declining Bering Sea sea ice concentrations (BSICs) in MarchThe Rossby wave train and the sea surface temperature anomalies in Northwest Atlantic bridge the declining BSIC in March and the cooling over NEA in June [ABSTRACT FROM AUTHOR]