关键词: 东北地区, 寒潮, 特征, 气候变暖, 响应

Abstract:

Based on the daily average air temperature and minimum air temperature data of 164 meteorological stations in Northeast China from 1961 to 2016， according to the Chinese national standard Grade of cold wave （GB/T 21987—2017）， we applied linear trend， trend coefficient， Mann-Kendall test， wavelet analysis and other analytical methods， and calculated the occurrence frequency， temperature drop and continuous days of the cold wave process of the stations， and spatial and temporal distribution characteristics of the cold wave in Northeast China were analyzed. The results show that the winter average air temperature of each station has a small correlation with cold wave days of three types （super-strong cold wave， strong cold wave and cold wave）. The colder areas with lower average temperature in winter and the warmer areas with higher temperature have little difference in the number of cold wave days. There are obvious regional differences in the spatial distribution of the three types of cold wave days. There are relatively more in high-altitude areas， and relatively few in low-altitude and plain areas. This conclusion is consistent with the actual occurrence of cold waves. The distribution characteristics of the three types of cold waves are determined by the cold wave path. When cold air enters from the east， middle， and west routes， the Greater Khingan Range and west side of the Changbai Mountains are most affected， and the Songliao Plain on the east side of the Greater Khingan Range is affected by the foehn effect and low altitude factors. The cold air gradually degenerates， the degree of influence gradually decreases and weakens； the Sanjiang Plain is affected by the regional climate and the blocking effect of the Lesser Khingan Range and the Changbai Mountains on the cold air， the cold wave is weaker， and the number of days is less. On the annual scale， the number of days and station-times of the three types of cold waves showed a decreasing trend from 1961 to 2016， and the rate of decrease was super strong cold wave > strong cold wave > cold wave； On the decadal scale， the three were relatively high from the 1960s to the end of the 1970s， and entered a relatively small period since 1980. There was a small increase after the mid-2000s， but the magnitude was significantly smaller than that of the 1980s. The rate of decrease means that the frequency of cold waves has increased since the beginning of the 21st century， but the long-term downward trend has not changed. Both the number of cold wave days and the number of station-times have obvious short-term periodic changes of 3 to 5 years. Before the 2000s， the period was mainly about 3 years， and in the 2000s， the period was about 5 years. The spatial variation of winter temperature in Northeast China from 1961 to 2016 showed a consistent increase in the whole region， and 66% of the stations increased significantly. The mutation point of the winter temperature was detected in 1981. After the climate in Northeast China warmed， the number of cold wave days and station-times of the three types decreased significantly， with the most significant decrease in eastern Jilin and northeastern Liaoning.

Key words: Northeast China, cold wave, characteristics, climate warming, response