1961—2010年安徽省参考作物蒸散时空变化特征及成因

基于联和国粮农组织推荐的Penman Monteith公式和60个台站1961—2010年逐日气象观测资料，估算了安徽省的参考作物蒸散量(ET₀),在对ET₀空间分布特征和时间演变规律进行分析的基础上,定量探讨了安徽省影响ET₀变化的主导因素.结果表明: 研究期间,安徽省ET₀的年平均值约为878.58 mm·a^-1，夏季最大，冬季最小.年平均ET₀呈现由北向南、由低海拔向高海拔递减的空间分布特征.ET₀的变化主要归因于日照时数和风速,而气温和相对湿度的作用较小.由于日照时数和风速的共同负贡献明显超过气温和相对湿度的共同正贡献,导致安徽省ET₀整体上以-1.61 mm·a^-1的速率显著下降.ET₀在春季呈不显著的微弱上升趋势;夏季ET₀以-1.37 mm·a^-1的速率显著下降;秋、冬季的ET₀微弱下降,但趋势不显著.春、秋、冬季ET₀变化的主导因子是风速;夏季的主导因子是日照时数.ET₀变化的主导因子存在明显空间差异.有36.7%站点的年平均ET₀变化的主导因子是风速,主要分布在淮北南部和沿淮地区;其他大部分地区的主导因子都是日照时数.

Temporal-spatial variations of reference evapotranspiration in Anhui Province and the quantification of the causes.

In this paper, daily reference evapotranspiration (ET₀) was computed with the recommended FAO-56 Penman Monteith equation for Anhui Province using data collected 60 weather stations during 1961 to 2010 and its temporal spatial variations were characterized. The determining factors in ET₀ trends were inquired into through partial derivative quantification analysis for the study region. Results showed that the mean annual ET₀ was 878.58 mm·a^-1 over the whole region during the study period. ET₀ was the highest in summer and the lowest in winter. The mean annual ET₀ decreased from the north to the south and from low altitude regions to high altitude regions. Both sunshine duration and wind speed were the dominant factors contributing to the interannual change of ET₀, with less contribution from air temperature or relative humidity. The annual ET₀ showed a general decline at a rate of -1.61 mm·a^-1 owing to a more negative contribution of sunshine duration and wind speed than a positive contribution of air temperature and relative humidity. ET₀ increased insignificantly in spring and decreased slightly in both autumn and winter. However, it decreased significantly at a rate of -1.37 mm·a^-1 in summer. The main impacting factor was wind speed in spring, autumn and winter, but it was sunshine duration in summer. Great diffe rences in the determining factors of the mean annual ET₀ existed from area to area in Anhui Pro vince. The wind speed was the determining factor for 36.7% of the whole stations distributing in the southern part of the area north to the Huaihe River and the area along the Huaihe River, while the sunshine duration was the determining factor for the other regions.