尉犁县地表蒸发量变化及影响因子分析

The Variation of Evaporation and the Analysis of Affecting Factors in Yuli County

分析了尉犁县小型蒸发皿(直径20cm)蒸发量1970年至2006年之间变化情况,发现其呈线性减少的态势,分析在春、夏、秋、冬四季中变化情况,同样也保持此变化规律,只是强度不同。夏季蒸发量最大且下降的幅度最明显,其次是秋季、春季,最后是冬季,年均蒸发量最少,且下降趋势最不明显。研究这一变化规律的相关性,发现年均蒸发量与相对湿度、年平均风速在0.01显著水平上相关,与年平均最大风速在0.05显著水平上相关。这种相关性在每个季节中的表现不尽相同。春季蒸发量与相对湿度、平均风速在0.01显著水平上相关,与最大风速在0.05显著水平上相关;夏季和秋季的蒸发量与相对湿度、平均风速在0.01显著水平上相关;冬季不具有这种相关性。蒸发量与相对湿度、8成以上低空云量出现日数负相关,与年平均风速、最大风速、2成以下低空云量出现日数正相关,除研究相对湿度、风速、不同成分低空云量出现日数与蒸发量间的相关性以外,还考虑了积温、降水量和日照时数等因子,这些因子与蒸发量关系不大。

By analyzing the variation of surface evaporation from 1970 to 2006 in Yuili County, we found its trend to be linear decrease, and by researching the rule of variation in four seasons, the same variation trend was kept with only the different intensity. The evaporation was the largest and its extent of decrease was the strongest in summer, and it was followed by autumn and spring, winter is final. In winter, the mean evaporation was the least, and the decreasing trend was the weakest of all. By researching the rule of correlation of the variation with other factors, we found the variation of vapour transportation from the surface to atmosphere was positive correlation with the relative coYre dity latio and the year average wind speed at the 0.01 significance level, and to be positive n with the year average maximum wind speed at the 0.05 significance level. The correlation had a different representation in the every season. In spring, the variation of vapour was a high correlation with the relative humidity and the average wind speed at the 0.01 significance level, and to be correlation with the maximum wind speed at the 0.05 significance level. In summer and autumn, the variation of vapour was a high correlation with the relative humidity and the average wind speed at the 0.01 significance level. There was not this kind correlation in winter. Evaporation in winter was a negative correlation with the relative humidity and the days while low altitude cloud cover to be beyond 80 percent, and to be a positive correlation with the year average wind speed, maximum wind speed and the days while low altitude cloud cover to be below 20 percent. Besides researching the correlation of factors said above, we took into account the accumulated temperature, the precipitation and the sunshine-hour etc., but there were no correlation with these factors.