影响山东参考作物蒸散量变化的气象因素定量分析

根据山东省1961-2010 年90 个气象站的逐日气象观测数据,采用计算参考作物蒸散量(ET₀)的Penman-Monteith 模型方法,分析了山东省ET₀对最高气温、最低气温、风速、日照时数、相对湿度的敏感性,并结合各气象要素的多年相对变化定量探讨了影响ET₀变化的主导因素。结果表明:近50 a 来,山东平均ET₀以-1.818 mm/a的趋势减少,夏季减少趋势最显著,1983 年前后ET₀发生突变。各气象要素对ET₀变化的敏感区域、与ET₀相关性地域差异明显。虽然平均风速和日照时数的敏感系数较低,但其减小趋势极显著,多年相对变化较大,使平均风速成为ET₀变化负贡献最大的气象要素,日照时数次之,最高气温贡献最低,相对湿度在沿海地区的正贡献较大。年、春、秋和冬季对ET₀变化的主导因子是平均风速,夏季是日照时数,半岛大部分地区一年四季的主导因子是相对湿度。突变后主导因子是平均风速的站点明显减少,主导因子为相对湿度的站点明显增多,由于夏季日照时数极显著减少,导致突变后夏季大多数站点对ET₀变化的主导因子为日照时数。

Quantitative Analysis of Climate Factors for Potential Evapotranspiration Changes in Shandong

Based on the daily data from 1961 to 2010 of 90 meteorological stations in Shandong Province, the changes of potential evapotranspiration (ET₀) were studied by analyzing the sensitivity coefficients of ET₀ to average wind speed, relative humidity, sunshine duration, daily maximum temperature and daily minimum temperature together with the relative changes of these climate factors by using the Penman-Monteith method recommended by FAO. The results showed that the annual ET₀ was decreasing with the speed of -1.818 mm/a, and it is more significant in summer. The mutation of annual ET₀ happened around 1983 and the annual ET₀ increased indistinctly after that. The influence of average wind speed on the changes of ET₀ was greater in northwest Shandong and was less in the coastal area. The influence of average relative humidity on the changes of ET₀ was larger in the peninsula and was less in the middle mountain area. The influence of sunshine duration on the changes of ET₀ was greater in southwest Shandong and south Shandong. The influence of maximum temperature on the changes of ET₀ was greater in southwest Shandong, west Shandong, and north Shandong. The correlation between climate factors and the changes of ET₀ was significantly different in space. The changes of ET₀ was primarily attributed to the wind speed due to its significant trends of decreasing, and followed by sunshine duration. The maximum temperature and the minimum temperature had a little positive contribution to the change of ET₀. The positive contribution of relative humidity was greater in the coastal area. The main impacting factor was the wind speed generally in a whole year, and it was so in spring, autumn and winter, but it was sunshine duration in summer. However the peninsula is an exception, that the relative humidity was always the main factor. The sites dominated by the wind speed reduced obviously after the mutation, but that dominated by the relative humidity increased evidently. Because of the significant decrease of sunshine duration in summer, the main impacting factor in summer was sunshine duration in most areas after the mutation.