The Connectivity of the Winter North Atlantic Oscillation (NAO) and the Summer Okhotsk High

[摘要] We statistically investigated winter-summer climatic connectivity between the winter North Atlantic Oscillation (NAO), and the summer Okhotsk High. We found that the winter NAO persistently influences the surface air temperature, snow cover over the Eurasia continent, sea ice and SST around the Barents Sea region from winter to summer. The warm air temperature anomalies in East Siberia make a preferable condition for upper-level blocking. Warm signals around the Barents Sea region excite the Rossby wave propagating toward the Sea of Okhotsk. In addition, regional persistency of the wintertime local phenomena, and their possible influence on the summertime Okhotsk High is examined. The negative phase of the winter NAO is related to the winter and spring heavy sea ice in the Sea of Okhotsk. The heavy spring sea ice in the Sea of Okhotsk brings about the cold SST around the Sea of Okhotsk. However, since the Okhotsk High does not have correlation with the SST around the Sea of Okhotsk in the previous month, the local connection of the sea ice in the Sea of Okhotsk with the summer Okhotsk High is unlikely. Associated with an enhanced Okhotsk High, cold SST anomalies appear to the east of Japan. This cold SST anomaly is a response to the cold air advection associated with the Okhotsk High. We suggest that the winter NAO remotely regulates both the winter sea ice, and the summer Okhotsk High.

[学科分类] 大气科学