1981—2010年西藏怒江流域潜在蒸发量的时空变化

 利用1981—2010年怒江流域9个站月平均最高气温、最低气温、降水量、风速、相对湿度、日照时数等资料，应用Penman-Monteith模型，采用气候倾向率、R/S等方法分析了潜在蒸发量变化的趋势性和持续性，并探讨了影响潜在蒸发量的气象因子。结果表明：近30年怒江流域四季潜在蒸发量趋于减少，年潜在蒸发量以18.4 mm?(10a)-1的速率显著减少。夏、秋、冬季和年潜在蒸发量具有持续性，未来将持续减少，尤其是冬季。在年代际尺度上，四季潜在蒸发量1980年代为正距平，1990和2000年代均为负距平。风速减小是四季潜在蒸发量减少的主要因素，不过春季潜在蒸发量的减少与降水量的显著增加也有关，且夏季气温日较差的显著变小对潜在蒸发量减少的作用不可忽视。

Spatial and Temporal Changes of Potential Evaporation over the Nujiang River Basin in Tibet During 1981-2010

The tendency and persistency of potential evaporation in the recent 30 years were analyzed based on the observational data of monthly average maximum temperature,minimum temperature,precipitation,wind speed,relative humidity,and sunshine duration of 9 stations in the Nujiang River basin in Tibet from 1981 to 2010 by linear trend analysis and Rescaled Range(R/S) analysis,as well as the Penman-Monteith model.And the relationships between potential evaporation and influential elements,such as sunshine duration,mean wind speed,and precipitation,were also discussed.The results show that the seasonal potential evaporation decreased during 1981-2010.Also,a negative trend of annual potential evaporation,i.e.,a rate of-18.4 mm·(10a)-1 significant at the 95% confidence level,was detected.The results of R/S analysis show that the summer,autumn,winter,and annual series of potential evaporation were persistent and it will assume continuous decrease in future,especially in winter.From the 1980s to the 2000s,the decadal anomaly of potential evaporation was positive in the 1980s,whereas negative in the 1990s and the 2000s.It is thus obvious that the decrease of potential evaporation was mainly caused by the significant decrease of wind speed in all seasons,however in spring it was also correlated with significant increase in precipitation,and in summer it might also be related to decrease in daily temperature range.