Research On Extreme Climate Change In Tarim Basin And Its Surroundings

Based on the materials of temperature and rainfall from1961to2009, theresearch on extremely changeable climate rules of Tarim Basin and its surroundingsis conducted, and the main results can be concluded below:The temperature extreme events can be summarized as below: yearly extremehigh temperature and low temperature in Tarim Basin and its surroundings are raisedin wave, worming trend were0.07℃/10a,0.14℃/10a, annual extreme lowtemperature variation was higher than the annual extreme high temperature in extentchange, and mutated in1978. The number of extreme high temperature days is raiseddistinctly, and that of extreme low temperature is decreased obviously. There is anincreasing tendency of seasonal extreme high temperature and low temperatureexcept winter, and the number of extreme high temperature days appears increasingtendency while that of extreme low temperature presents decreasing tendency. Thereis a great consistency of tendency distributions of extreme high temperature and lowtemperature and those of extreme high temperature days and extreme lowtemperature days in Tarim Basin and its surroundings. In the period of research, theextreme low temperature days appear decreasing in Tarim Basin and its surroundingsexpect for the middle area of Tarim Basin, especially the western part. However,there is a negative tendency of extreme high temperature days in western areas, mostparts of northwest areas, northern, some parts of southern including the middle areaof Tarim Basin, and the rest areas have increasing tendency of day extreme hightemperature, especially in the some parts of northeast and southeast areas. Moreover,there is a remarkable cycle change of yearly extreme temperature, and the warm andthe cold have a cycle exchange.The precipitation extreme events can be concluded as below: there is anincreasing tendency of rainfall, its frequency and its intensity. Linear trend raterespectively in2.85mm/10a、1.6d/10a、0.03mm/d/10a. Extreme precipitationfrequency and extreme precipitation are in good positive correlation, and they are allreached the maximum value in1996, and mutated in1981.The proportion thatextreme take up in the total precipitation quantity tends to increase, variation trendfor0.66%/10a and space distributions of tendency coefficients of extreme rainfalland extreme rainfall days are highly similar in Tarim Basin and its surroundings.There is an increasing tendency of yearly extreme rainfall and extreme rainfall daysin the north and the west areas, while the yearly extreme rainfall intensity decreases at the same areas. The change of yearly extreme rainfall and yearly extreme rainfalldays appears obvious in the middle area of Tarim Basin. In the eastern, there is adecreasing tendency of yearly extreme rainfall and yearly extreme rainfall days, butthe extreme rainfall intensity increases. Season is a kind of obvious factor of extremerainfall, which focuses on summer. There is an increasing space tendency forseasonal extreme rainfall, its frequency and its intensity in western areas, northernareas and northwest areas, while there is a decreasing tendency in southern areas andeastern areas. What’s more, there is a remarkable cycle change of yearly extremerainfall, and the dry and the wet have a significant alternation.The relation of average and extreme temperature and extreme rainfall is thatcompared the correlation of yearly average and extreme events with that ofseasonable average temperature and extreme temperature events, the correlation ofthe former appears apparently. The relationship of seasonable average temperatureand extreme temperature events mainly reflects on extreme temperature and little onextreme rainfall.