青海省东部农业区参考作物蒸散量的变化及对气象因子的敏感性分析

Changes of Reference Crop Evapotranspiration and Sensitivity Analysis of Meteorological Factors in Eastern Plateau Agricultural Region of Qinghai Province

使用FAO推荐的Penman-Monteith公式计算了青海省东部农业区7个气象代表站的逐日参考作物蒸散量(ET0),运用多窗谱方法(MTM)对青海省东部代表站的ET0的变化周期进行了分析,同时,分析了影响ET0的主要气象要素的变化趋势,运用基于偏导数的敏感系数法分析了生长季ET0对气温、日照时数、相对湿度、风速的敏感性,结果表明,青海省东部农业区的7个站点有比较一致的19.23～22.22 a的周期;整个东部农业区的气温(最高温度、最低温度、平均温度)呈明显的上升趋势,日照时数、风速、相对湿度则随纬度的变化而趋势不同,北纬36°以南的两个站日照时数、风速均有增加的趋势,相对湿度则减小,以北的5个站则呈相反的变化;ET0对日照时数最为敏感,其次是气温、相对湿度和风速;敏感系数在整个生长季随气象因子的变化而变化,日照时数敏感系数呈波动状,最大值出现在4月,最小值出现在9月,气温敏感系数呈现单峰型变化,最大值出现在7月,风速敏感系数则呈单谷型变化,最小值出现在7月。

The reference crop evapotranspiration （ETo ） in the eastern plateau agricultural region of Qinghai Province was calculated by Penman-Monteith formula based on meteorological data of seven meteorological observation stations. The main change circle as well as the main trend of main meteorological elements were analyzed with Multi-Taper Method （MTM）. Sensitivity coefficient of temperature, sunshine duration, relative humidity, wind speed sensitivity in growing season of eastern Qinghai were studied based on partial derivatives. The results showed that the seven stations we used have a constant 19. 23 -22. 22-year changing cycle, temperature （including maximum temperature, minimum temperature and average temperature） showed a significant upward trend in the whole region. Sunshine duration, wind speed and relative humidity differed with the variation of latitude. In south of latitude 36°, sunshine duration and wind speed showed a significant upward trend while relative humidity decreased, the other five stations in north of latitude 36° had an opposite trend; that sunshine duration was the most sensitive variable to ETo in general for the region, followed by air temperature and relative humidity, wind speed had the least impact. Sensitivity coefficient in the whole growth season changed with meteorological factors. The sensitivity coefficient of sunshine duration in the whole growth season fluctuate insignificantly, the maximum value appeared in April, and the minimum value appeared in September. The sensitivi- ty coefficient of temperature varies in a single curve and the maximum value appeared in July. The sensitivity coefficient of wind speed varies in a single valley and the minimum value appeared in July.