An Abrupt Change of Winter Surface Air Temperature over the Northern Part of Korean Peninsula in the Late 1980s and Related Atmospheric Circulation Variability

The aim of this study is to detect the variation of winter surface air temperature (SAT) over the northern part of Korean Peninsula (NPKP) for the period of 1949-2020 under global warming, as well as to investigate its possible mechanisms. All temperature data used for the study were obtained from representative 37 weather stations over NPKP. Results are as follows. 1) Winter temperature anomaly series manifested a clear shifting point in the late 1980s, with upward rate of about 0.19 degrees C per decade for the period of 1949-2020, and those were generally smaller than normal year prior to the shifting point, but were greater after 1988. 2) Spatial patterns of first mode of empirical orthogonal function before or after the shifting point in the Northern Hemisphere had reversely alternated, as an evidence describing the possible linkage between negative (positive) phase of Arctic oscilliation and cold (warm) winter over the study area. 3) A schematic diagram shows the connections of atmospheric circulation indices with the winter temperature over the study area: the East Asian trough had the best rela-tionship with winter SAT over the study area among the East Asian winter monsoon components affecting East Asia. However, the possible causes of the winter temperature variation in the study area need to be further investigated.