纵向岭谷区参考作物腾发量变化的特点和趋势

以Penman Montieth方程分析了西南纵向岭谷区大理、元江、保山、昆明、景洪站46～48年的逐日ET₀及其余25个站1961～2000年逐月ET₀系列。研究结果表明：日最高温度是年内ET₀变化主导因素，年际变化主要受日照时数影响，个别站为最高气温或风速，短期ET₀变化与雾无直接关系。利用Mann-Kendall法对各站年际、年内分季节ET₀趋势检验，56.7%站点的年ET₀呈显著增加趋势，分布于澜沧江耿马-思茅-勐海一带以及横断山区维西、福贡等地。分季节逐日ET₀变化趋势为，昆明夏秋季显著下降，景洪冬春季显著增加，元江、保山、大理有增有减。降水量增加、气温升高，蒸发和日照时数减少，导致80%的站ET₀呈下降趋势，湿润指数普遍增加。

Dynamic variation characteristics and tendency of reference crop evapotranspiration in the longitudinal range gorge region

Penman Monteith equation was used to compute daily ET₀ for five stations: Dali, Yuanjiang, Baoshan, Kunming, and Jinghong, based on the history meteorological data range from 46 to 48 years, and monthly ET₀ series of the other 25 meteorological stations from 1961 to 2000. The most important influence factor of daily ET₀ is daily maximum temperature. The key influence factor of yearly ET₀ is sunshine, but is wind speed and maximum temperature in some stations. And the fog is not relative with ET₀. Then, Mann-Kendall method was used to test seasonal and yearly ET₀ series of five stations. Results indicate that yearly ET₀ series for 56.7% of weather stations increase significantly, which locates at Gengma, Simao, Menghai of Lancang River basin, and Weixi, Fugong of Hengduan Mountainous Area. Daily ET₀ in summer and autumn at Kunming station markedly decrease, while dialy ET₀ in winter and spring at Jinghong station increase, but daily ET₀ at Yuanjiang, Baoshan, and Dali station changes irregularly. The change trend of main meteorological factors is that precipitation and temperature increase, evaporation and sunshine decrease, moisture index increase too, which make ET₀ series of 80% stations decrease observably.