澜沧江流域极端天气灾害特征及波动趋势

基于中国气象局国家气象信息中心提供的澜沧江1961—2010年气象资料,采用小波分析、EMD分解、CI指数、均生函数逐步回归模型、相关分析等方法,探讨19世纪末至21世纪初澜沧江流域极端天气灾害的变化特征,及其区域极端灾害变化和全球气候变化之间的联系。结果表明:(1)1961—2010年50a期间,年降水量趋于稳定,略有上升,但上升率较小,只有3.1848。年降水量距平分布图反映了降水量南多北少的区域差异,正负距平之间在-2到2之间,北部干旱出现的几率较大。(2)近20年来,澜沧江区域干旱次数明显上升,而澜沧江流域年暴雨频次在过去50a和未来的20a内没有明显的增加趋势,干旱频次未来20年内呈斜率0.2635的上升态势,未来该区域极端天气灾害主要是干旱灾害。(3)该区域降水和暴雨频次存在多尺度特征,两种研究方法都得到澜沧江流域降水量存在2、7、15a的变化周期,只是两种方法得出的主周期不同,EMD方法比小波方法更适合处理非平稳、非线性信号,可以认为澜沧江流域降水量存在2、7、15a的变化周期,且主周期为准2a。(4)降水量和暴雨频度序列的IMF1和IMF2周期在2—7 a之间,与ENSO在年际变化上的信号相吻合,推断澜沧江流域暴雨和干旱灾害与ENSO有重要联系,且随着气温升高干旱灾害频次明显增加,显示区域极端气温灾害的变化与全球气候变暖有某种关联,是全球气候变化的区域响应表现形式之一。

Research on characteristics of extreme weather disasters and fluctuations trend on Lancang river basin

The meteorological data from1961 to 2010 about the Lancang region which was provided by National Meteorological Information Center were used to to explore the link between the variation of the Lancang River Basin extreme weather disasters in the late 19th century to the early 21st century, and its regional extreme disasters change and global climate change the method whose using wavelet analysis, EMD decomposition, CI index, mean generating function stepwise regression model, mutation testing and correlation analysis etc were been used. It is showed that by the results: (1) Annual precipitation is stabilized, rose slightly, but the rate of rise is small, only 3.1848 in the 50-year period of which from 1951 to 2010. Annual precipitation anomaly maps to reflect regional differences in precipitation in the south than in the north, between positive and negative anomalies between -2 to 2, the probability of occurrence of the northern arid. (2) In the past 20 years, the Lancang area arid the number was significantly increased by the Lancang River Basin annual rainstorm frequency times in the past 50 years and the next 20 years there is no obvious increase trend, drought frequency times the next 20 years showed a slope of 0.2635 the rising trend, the future of the region of extreme weather disasters, mainly drought disaster. (3) There have multi-scale features about regional precipitation and storm frequency, whose 2a, 7a, 15a change cycle in Lancang River Basin precipitation has been proved by two research methods, but whose main cycle by two method is different. It is showed that EMD method is more suitable than wavelet method to deal with non-stationary, non-linear signal, concluded that the precipitation of the Lancang River Basin 2a, 7a, 15a change cycle, and primary cycle prevail 2a. (4) The cycle of IMF1 and IMF2 about precipitation and frequent rainstorms the degree sequence is between 2-7 a, which is coincided similar to that of ENSO. It was inferred by it that there is important connection between the storms and drought disasters of Lancang River Basin and ENSO. As the temperature increased significantly increased frequency of drought disasters, all of those showed that extreme temperature disasters, climate change and global warming have some connection to one of the manifestations of global climate change, regional response.