宁夏冬季气温的变化及同期500hPa环流特征量的变化特征

Change characteristics of air temperature in Ningxia and of atmospheric circulation of 500 hPa in Winter

通过近40多年来宁夏冬季气温的变化进行了研究,结果表明:宁夏冬季气温总趋势是变暖的,冬季平均气温在1985年前后发生突变,突变后升温最明显的是中部干旱带;宁夏冬季气候变暖与大区域有不同之处,1967-1990年宁夏冬季升温过程,最低气温是主要的,但1990年以后宁夏冬季的变暖,并不完全是由于最低气温的变暖而形成,最高气温的变暖也是20世纪90年代以来宁夏冬季气候变暖的重要特征;宁夏极端气温变化具有明显阶段性特征,80年代末期以后极端最低气温的变率明显增大;冬季北半球500 hpa极涡面积、亚洲西风环流指数、东亚大槽位置、西太平洋副热带高压强度与宁夏冬季平均气温有较为一致的年代际气候特征;小波分析发现,以上环流特征量与宁夏冬季平均气温存在相同的4年左右的主周期变化,且在时、频域上有较为一致的对应关系。

In this paper, the change of air temperature in Ningxia Hui Autonomous Region, China, is researched using the data of average, average maximum and minimum and extremely maximum and minimum temperatures observed by 23 meteorological stations in Ningxia during the period of 1961-2004 and the data of the 500 hPa general circulation. The results are as follows： （1） The air temperature in Ningxia in winter was increased during the period of 1962-2003; a sudden climate change occurred around 1985, after the sudden climate change, the average temperature in winter, average minimum and maximum temperatures were increased by 1.7℃, 1.5℃ and 2.0℃ respectively than that before the sudden climate change, and the temperature increase is the most significant in the central arid regions after the,sudden climate change; （2） The climate warming in Ningxia in winter is different to some extent from that in other regions, that is the climate warming in Ningxia in winter is affected by the increase of both minimum and maximum temperatures since the 1990s; （3） The change of the extremely minimum temperature in Ningxia in winter is significantly periodical, and the change rate of the extremely minimum temperature has been significantly increased; （4） Corresponding to the decade temperature increase, the climate change since the mid-1980s is also revealed by the eigenvalues of 500 hPa general circulation, such as the change in the North Hemisphere vortex area in winter, Asian west wind circulation index, position of East Asian trough, and intensity of subtropical high in West Pacific Ocean; the results of wavelet analysis reveal that the change of average temperature in Ningxia in winter accords with that of the eigenvalues of 500 hPa general circulation, and they have the same 4-year periodical change.