Interdecadal variations of the East Asian winter surface air temperature and possible causes

Abstract

Using the NCEP/NCAR and JRA-25 monthly analysis data from 1979 to 2011, this paper analyzes the interdecadal variations of winter (Dec.-Feb.) mean surface air temperature (SAT) over East Asia by means of the empirical orthogonal function (EOF) analysis method. Two dominant modes were extracted, with the leading mode basically depicting a sign consistent SAT variation and the second mode describing a meridional dipole structure between the northern and southern parts of East Asia. These two modes can explain more than 60% of the variance. The leading mode is closely related to the intensity of Siberian high and the East Asian winter monsoon. The second mode exhibits a notable interdecadal shift in the late 1990s, with a turning point around 1996/1997. Winter SAT in the northern (southern) part of East Asia tends to be cooler (warmer) since the late 1990. Winter sea level pressure (SLP) differences between 1997-2011 and 1979-1996 show negative (positive) anomalies over southern (northern) Eurasia. At 500-hPa, an anomalous blocking high occurs over northern Eurasia, while a cyclone anomaly appears over northern East Asia. In addition, the upper-level East Asian jet stream tends to shift northward and become stronger after the late 1990. Indeed, the interdecadal shift of winter SAT over East Asia is dynamical consistent with changes of the large-scale atmospheric circulation in the late 1990s. The result indicates that previous autumn sea surface temperature (SST) in the North Atlantic Ocean, the Northern Indian Ocean and the western North Pacific Ocean, as well as sea ice concentration (SIC) in the northern Eurasia marginal seas and the Beaufort Sea also experienced obvious changes in the late 1990s. In particular, the interdecadal shifts of both SST in the North Atlantic Ocean and SIC in the Arctic Ocean and its marginal seas are well coherent with that of the winter SAT over East Asia. The results indicate that the interdecadal shift of East Asian winter SAT may be related to changes in the North Atlantic SST and the Arctic SIC in the late 1990s.

Thirteen years of observations on biomass burning organic tracers over Chichijima Island in the western North Pacific: An outflow region of Asian aerosols

“…The enhanced precipitation scavenges more aerosol particles from the atmosphere, resulting in the lower concentrations of BB tracers in winter over the WNP [ Hu et al ., ]. The increase in the wintertime surface air temperature may result in a decrease of domestic BB activities in East Asia, possibly depressing atmospheric transport of BB products over the WNP [ Kim et al ., ; Yang and Wu , ].…”

“…The periods of high fire/hot spot frequency increased from 2006 to 2013 (Figures S2a–S2d), indicating that the BB activities are recently increasing in the East Asian regions [ Gajović and Todorović , ], which may be associated with the fire activities under drier conditions. This may be associated with the recent increase of wintertime ambient temperature in Southeast Asia [ Yang and Wu , ] and annual temperature in Siberia [ Konya et al ., ], which may cause drier condition and thus enhance fire activities. Air mass trajectories further support that the air masses had passed through Siberia, East Asia, and the Russian Far East before arriving at Chichijima (Figure b and Figures S1a and S1b).…”

Assessment of the response of the East Asian winter monsoon to ENSO‐like SSTAs in three U.S. CLIVAR Project models

“…The unique geographical features of East Asia lead to its climate characteristics and severe climate variabilities (Yang and Wu, ). According to results (Figure ), all of the models can reliably simulate the climatology of the EAWM‐related circulation with realistic features.…”

Month-to-Month Variability of Autumn Sea Ice in the Barents and Kara Seas and Its Relationship to Winter Air Temperature in China

“…Severe cold events and anomalously heavy snowfalls have frequently affected most midlatitude regions of the Northern Hemisphere (NH), including major industrialized centers [2,3]. Along with this unforeseen cooling trend in the midlatitude regions of the NH, both the Cold Siberian High and the East Asian winter monsoon exhibit a substantial decadal intensification, leading to more active cold air outbreaks in China [4,5]. Recent studies documented that there may be some physical linkages between the recent reduction of ice in the Arctic Ocean and cooling in the midlatitude continents of the NH through the anomalous atmospheric circulation response of sea ice loss [6].…”

“…e variations of the sea ice in the BK are associated with the Arctic Oscillation (Arctic Dipole pattern) by inducing cross-Arctic-like (Eurasian) teleconnection wave-train patterns that lead to an intensification of cold surge activity in China [26]. e SST anomalies in the NH and the changes in Arctic sea ice were involved in the interdecadal changes in the winter surface air temperature (SAT) over East Asia that occurred approximately during the mid-1990s [4,27].…”