嫩江流域参考作物蒸散量时空变化及其气候归因

为了解嫩江流域参考作物蒸散量(ET₀)的时空变化特征,明确气候因素对流域ET₀的影响,应用Penman-Monteith公式计算1970—2019年嫩江流域各站点日ET₀,分析ET₀的时间变化趋势和空间分布格局,采用敏感性分析方法定量研究ET₀对气象因子敏感性程度,并进一步探究各气象因子对ET₀变化的贡献。结果表明: 研究期间,嫩江流域年际ET₀整体呈不显著减少趋势,春、夏、秋季ET₀波动减少,冬季波动增加;ET₀整体呈从东南向西北递减趋势。ET₀在时间和空间尺度上均表现为对相对湿度的敏感性最高;平均气温、相对湿度和风速的敏感性系数逐渐增强,日照时数的敏感性系数逐渐减弱。大兴安岭北部和小兴安岭地区ET₀对平均气温较敏感;大兴安岭南部和松嫩平原地区ET₀对风速较敏感。风速是影响全年及春、秋、冬季ET₀变化的主导因素,日照时数是影响夏季ET₀变化的主要因素。大兴安岭北部和小兴安岭地区平均气温和相对湿度对ET₀的贡献率最大,松嫩平原地区风速的贡献率最大。

Spatio-temporal variation of reference crop evapotranspiration and its climatic mechanism in Nenjiang River Basin,China

To understand the temporal and spatial variations of reference crop evapotranspiration(ET₀) in Nenjiang River Basin,and clarify the effects of climatic factors on ET₀,we calculated the daily ET₀ of each station in Nenjiang River Basin from 1970 to 2019 by Penman-Monteith formula,analyzed the temporal variation trend and spatial distribution pattern of ET₀.We further quantitatively examined the sensitivity of ET₀ to meteorological factors by sensitivity analysis,and explored the contribution of meteorological factors to ET₀ changes.The results showed that ET₀ generally showed an insignificant decreasing trend during the study period in the Nenjiang River Basin.ET₀ decreased in spring,summer,and autumn,but increased in winter,and decreased from southeast to northwest.ET₀ had the highest sensitivity to relative humidity at both temporal and spatial scales.The sensitivity coefficients of mean temperature,relative humidity and wind speed increased gradually,while that of sunshine hours decreased gradually.ET₀ was sensitive to mean temperature in northern Greater Khingan Mountains and Lesser Khingan Mountains,while to wind speed in southern Greater Khingan Mountains and Songnen Plain.Wind speed was the main factor affecting the change of ET₀ in the whole year,spring,autumn,and winter.Sunshine hours was the main affecting factor in summer.The mean temperature and relative humidity had the greatest contribution to ET₀ in the north of Greater Khingan Mountains and Lesser Khingan Mountains,and it was the wind speed in Songnen Plain.