中国气候异常变化与ENSO准四年循环的联系分析

ANALYSIS OF THE RELATIONSHIP BETWEEN THE CHINA ANOMALOUS CLIMATE VARIATION AND ENSO CYCLE ON THE QUASI-FOUR-YEAR SCALE

从月资料分析入手,分析了中国大陆地区的降水和气温异常与ENSO的联系。首先用REOF方法对降水和气温的变化进行分区分析,并讨论其年际变化特点。然后对降水和海温场、气温和海温场分别进行CSVD分析,讨论了在ENSO准四年循环的不同位相上,气温和降水的异常变化情况。结果表明:(1)在El Nino期间,我国东部地区,尤其是东北、长江中下游的江南地区降水偏多,容易发生洪涝,华北地区、黄河流域尤其是中部降水偏少,可能发生干旱。其中长江中下游的南部降水与赤道中东太平洋海温在准四年变化上关系密切,当中东太平洋海温达到最高值后约3个月,长江中下游的南部降水出现最大正距平。(2)在El Nino期间,东北容易出现低温天气,而其它地区尤其是河套地区及西南南部易出现高温天气。其中东北地区气温变化与赤道中东太平洋海温在准四年变化上关系密切,当中东太平洋海温达到最高值后约2个月,东北气温的负距平出现最低。La Nina阶段,情况与前述相反。

The relationship between the ENSO and abnormal variation of precipitation and temperature in the China is investigated based on the monthly data. Firstly, interannual variability of precipitation and temperature in different subareas has been discussed by use of REOF. Then, the variation of precipitation and temperature in the different phase of ENSO cycle is investigated by CSVD, respectively. Results show that, during the period of El Nin o, precipitation in the eastern China, especially in the northeastern China and Yangtze River valley, is much more than normal and is apt to flood. Precipitation in northern China and Huanghe River valley, especially in the middle reach of Huanghe River, is less than normal and is apt to drought. Precipitation in Yangtze River valley is closely related to the SSTA in central and eastern tropical Pacific on the QFO scale, and the precipitation variation lag behind SSTA about 3 months. For the variation of surface temperature, during the period of El Nin o, northeastern China usually colder than normal, and in other regions, especially in the Hetao region and southwestern China, are warmer than normal. The temperature in northeast China is closely associated with SSTA in eastern Pacific on the QFO scale and the surface temperature variation in the northeast China lags behind that of SSTA about 2 months.