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为了探索近57年(1956-2012年)元谋干热河谷地区不同时间尺度参照作物腾发量ET0特征,该文以实测的日和年微气象资料为基础,采用联合国粮农组织(FAO)推荐的Penman-Monteith方法计算日ET0,采用Mann-Kendall检验法分析年、季度、月和年内日参照作物腾发量的变化趋势和突变情况,并进行其与主要气象因子的通径分析。结果表明:元谋地区ET0总体上均呈现逐渐下降的趋势。年参照作物腾发量1983年以后下降趋势明显;季度参照作物腾发量在1984、1994、1985和1990年分别出现一二三四季度的明显下降;多年平均月ET0在4月达到最大值,12月份达到最小值;年内日ET0在4或5月份出现峰值。对ET0影响为正的因子按大小排列为平均风速u2、最低气温Tmin、平均气温T、日照n和最高气温Tmax,对ET0的影响为负的因子影响大小顺序为平均湿度、水汽压、降雨和气压。
In order to explore the ET0 characteristics of reference evapotranspiration at different timescales in Yuanmou dry-hot valley in recent 57 years (1956-2012), based on the measured daily and annual micrometeorological data and using the recommendations of the FAO Penman-Monteith method was used to calculate the daily ET0. The Mann-Kendall test was used to analyze the trends and abrupt changes of daily reference evapotranspiration (ECT) in year, quarter, month and year, and the path analysis was conducted with the main meteorological factors. The results show that ET0 in Yuanmou area shows a gradual downward trend. The annual amount of reference evapotranspiration had a significant downward trend since 1983; the seasonal reference evapotranspiration significantly decreased in 1984, 1994, 1985 and 1990 respectively; the average monthly ET0 reached the maximum in April, December reached its minimum; ET0 peaked in April or May during the year. Factors that positively influence ET0 are the average wind speed u2, the minimum temperature Tmin, the average temperature T, the sunshine n and the maximum temperature Tmax, and the factors that have a negative impact on the ET0. The order of the factors is average humidity, vapor pressure, rainfall and Pressure.