Research Of The Drought Characteristics In The Lancang River Basin And The Association With SST Anomalies

The Lancang regional National Meteorological Information Center,1961-201150years of meteorological data, using wavelet analysis, EMD decomposition, mean generating function stepwise regression model, correlation analysis etc. method to explore the link between the variation of the Lancang River Basin extreme weather disasters, and its regional change and global climate change. The results showed that:①According to the analysis of the first and the second EOF modal, the precipitation in overall precipitation in the northern basin of the spring and winter, precipitation is less than the south. On the contrary, precipitation in Summer is less in northern than in southern.In the past20years, the Lancang area arid the number was significantly increased by the Lancang River Basin annual rainstorm frequency times in the past50years there was no obvious increase trend, the future of the region of extreme weather disasters, mainly drought disaster.②CI index is calculated based on the Four Seasons light drought, severe drought in arid and arid special spatial frequency analysis. The basin is relatively arid region moves with the seasons, and the size of drought frequency with seasonal changes. CI index is calculated based on the analysis of drought frequency in the spring and summer drought area of the center is relatively small, while in autumn and winter drought frequency value is relatively large. Relatively arid area from spring to winter, moving from northwest to southeast. Z Index study found affected by the presence of a turning point in the1980s droughts in drought statistics, this result has been corresponding.③The regional precipitation and storm frequency multi-scale features exist, two research methods Lancang River Basin precipitation2a,7a,15a change cycle exists, the only two ways to come to the main cycle is different, EMD method is more suitable than wavelet method to deal with non-stationary, non-linear signal, concluded that the precipitation of the Lancang River Basin2a,7a,15a change cycle, and primary cycle prevail2a.④Correlation between the basin and the sea temperature is mainly concentrated in the winter and spring, through correlation test. IMF1and IMF2cycle frequency of precipitation sequence between2～7a, with the ENSO signal in the interannual variability of the match, a positive correlation with the SOI index. Inferred storms and droughts of Lancang River Basin have an important link to ENSO, and as Seasonal precipitation Lancang River Basin waters associated with changes in the area varies.