| Climate change is unequivocal. It changes the regional and even global evapotranspiration and redistribution under global warming clearly since 1990s. And it results meteorological disasters and climate events more and more,and regional water shortage problem is increasing prominent, especially in the extreme arid areas which climate sensitivity is strongly. This paper took the main stream of Tarim River as research and choose the potential evapotranspiration as a key factor to analy change characterics of different stage on climate and potential evapotranspiration,and discuss the main meteorological influence factors of different time-spactial on potential evapotranspiration, and quantifies sensitive range and spatio-temporal difference on potential evapotranspiration change under different influence factor using Mann-Kendall nonparametric mutation test, climate tendency rate, Penman-Monteith model, anolmaly correlation method and sensitivity analysis method in the main stream basin of Tarim River.The results showed that:1.The temporal-spatial distribution and change characteristics on climatic elements were revealed. (1) The annual average temperature in the main stream of Tarim River was downstream basin (11.5℃)> middlestream basin(11.1℃)> upstream basin(11.0℃), and warm season(spring,summer and autumn) average temperature was downstream basin(14.6℃,26.2℃ and 10.7℃)> upstream basin(14.4℃,24.2℃ and 10.7℃)> middlestream basin(13.6℃,24.3℃ and 10.3℃), cold season(winter) average temperature was upstream basin(-5.2℃)> middlestream basin(-5.3℃)> downstream basin(-5.7℃) and were summer> spring> autumn> winter, the highest value in July and the lowest value in January. The annual and seasonal precipitation were middlestream basin (63.7mm,12.7mm,36.6mm,10.8mm and 3.6mm)> upstream basin(58.4mm,11.5mm,34.4mm,9.4mm and 3.5mm)> downstream basin(31.7mm,5.1mm,22.5mm,2.9mm and 1.2mm) and were summer > spring> autumn> winte, the highest value in July and the lowest value in February.(2) The annual temperature and precipitation were increasing,aridity index was decreasing in the main stream of Tarim River since 1980s,and dynamic change on climate except downstream basin was cold dry-warm moist-cold dry. (2) The spring temperature was increasingly in the main stream of Tarim River after 2000. The amplification was middlestream basin(0.67℃/10a)> downstream basin(0.36 ℃/10a)> upstream basin(0.24℃/10a),the average temperature was decreasing significantly in summer,autumn and winter,and the largest damping in autumn and winter after 2000.2.The temporal-spatial distribution and change characteristics on potential evapotranspiration was proven.(1) The annual potentional evapotranspiration in the main stream of Tarim River was downstream basin (1759.6mm)> upstream basin (1694.2mm)> middlestream basin (1666.5mm), seasonal ETp of downstream basin was higher upstream basin,was higher middlestream basin and were spring> summer > autumn> winter, the highest value in May and the lowest value in February. (2) The annual ETp did not change significantly before 1970s, was decreasing after 1970s and was increasing gradually after 2000. And dynamic change on ETp was high-low-high.(2) The annual and sensonal ETp were increasing significantly in the main stream of Tarim River after 2000. The amplification on annual ETp was upstream basin (99.61mm/10a)> middlestream basin (92.36mm/10a)> downstream basin (78.21mm/10a) and the highest amplification on ETp was in spring which was middlestream basin (47.61mm/10a)> upstream basin (41.79mm/10a)> downstream basin(34.89mm/10a).3.The temporal-spatial difference and sensitive range of different influence factors on potential evapotranspiration change were quantified.(1) The annual ETp were controlled by average wind speed, sunshine hours, average relative humidity and precipitation in common, which less controlled by air temperature in main stream of Tarim River. And decreased on annual ETp bfore mutation point were controlled by decreased sunshine hours, decreased average wind speed,increased average relative humidity and precipitation in common, which less controlled by temperature and the ranking of climate sensitivity was RH>h>P,U>h>RH and h in main stream,upstream and middlestream of Tarim River. And increased annual ETp after mutation point were controlled by decreased minimum temperature, increased sunshine hours and increased (decreasde) average relative humidity in common and the ranking of climate sensitivity was RH>h, Tmin>h and RH>h in main stream,upstream and middlestream of Tarim River. And increased on annual ETp was controlled by increased average relative humidity and increased sunshine hours in common and the ranking of climate sensitivity was h>RH in downsteam basin. And decreased on annual ETp was controlled by decreased average relative humidity, decreased sunshine hours and raised minimum temperature in common,whiche the ranking of climate sensitivity was RH>h>Tmin in downsteam of Tarim River. (2) Seasonal ETp were controlled by average relative humidity, average wind speed, sunshine hours, precipitation and air temperature in common in the main basin of Tarim River. The changing on sasonal ETp before mutation point were controlled by average relative humidity, average wind speed, sunshine hours, precipitation,maximum and minimum temperature in common. Which the ranking of climate sensitivity were h, h>RH, RH>h>P, h>P>Tmax, Tmax>h>U, RH>h, h >RH,h>P>U, h, h, RH>h>P>Tmin, h>P and h, Tmax>RH>h, RH>h, RH>h >Tmax in main stream and every river basin. The changing on sasonal ETp after mutation point were controlled by average relative humidity, average wind speed, sunshine hours, precipitation and air temperature in common.Which the ranking of climate sensitivity were Tmax>T>h>Tmin>RH, h>RH, h, h>RH>P, Tmax>U> h>T, h, h>Tmax>RH, h>Tmin>RH>Tmax>P, Tmax>h>T>RH>Tmin, h>U> RH, RH>h>U, RH>h>P, T>Tmax>h>RH>P, T>h>Tmin, h and Tmin>h> U>P. |
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