黄淮海平原各农业亚区潜在蒸散量变化及其对气候要素的敏感性分析

潜在蒸散量是确定作物需水量的重要依据和基础，客观分析其时空变化及气候成因具有重要意义。本文以国家气象局整编的黄淮海平原40个站点近53a（1961-2013年）逐日气象资料，将黄淮海平原分为6个农业亚区，分别计算潜在蒸散量（ET0）及其对气候要素（气温、相对湿润度、太阳辐射和风速）的敏感系数，并分析其变化特征。结果表明：从各区年、季ET0的平均值看，黄淮海平原各亚区都是夏季ET0最高，秋季和冬季以鲁西平原鲁中丘陵水浇地旱地二熟区（Ⅳ区）最高。从各区年、季ET0变化倾向率看，6个农业亚区夏季ET0均呈显著递减趋势，其中南阳盆地水浇地旱地二熟区（Ⅴ区）减幅最大，而春季ET0表现为燕山太行山山前平原水浇地二熟区（Ⅱ区）和江淮平原丘陵麦稻两熟区（VI区）呈显著递增的变化趋势、冬季Ⅱ区ET0呈现显著递增的变化趋势；从各区年、季ET0敏感系数的平均值和变化倾向率看，春、秋、冬季和年ET0对相对湿度最敏感，夏季ET0对太阳辐射最敏感；ET0对太阳辐射和相对湿度分别呈正向和负向敏感，且敏感性在时间序列上呈减弱趋势；相对湿润度和风速在环渤海山东半岛滨海外向型二熟农渔区（Ⅰ区）、太阳辐射和气温在VI区形成高值区，说明ET0在黄淮海平原Ⅰ区对相对湿润度和风速、在VI区对太阳辐射和温度较敏感。

Variation in Potential Evapotranspiration and Its Sensitivity Coefficients to Climatic Factors in the Huang-Huai-Hai Plain

Potential evapotranspiration (ET0) is generally accepted to be an important element of the hydrological cycle, and changes in sensitivity coefficients of ET0 are of great significance for agricultural water use planning, irrigation system design and management. Potential evapotranspiration and their sensitivity coefficients in four seasons and entire year were calculated by the Penman-Monteith methods and partial derivative equation across six agricultural sub-zones of the Huang-Huai-Hai plain (3H plain) from a data set of daily climate variables in 40 meteorological stations during the period from 1961 to 2013. The highest value of ET0 was found in summer, whilein autumn and winter in the fourth zone. A decreasing trend for ET0 was detected in summer in these six sub-zones in recent 53 years and maximum amplitude was found in fifth zone. However, an increasing trend for ET0 was detected in second and sixth zone during spring and in second zone during winter. Relative humidity was considered to be the most sensitive variable for ET0 in spring, autumn, winter and whole year and solar radiation was the most sensitive variable for ET0 in summer. Moreover, the positive and negative values of sensitivity coefficients were recognized as solar radiation and relative humidity respectively for ET0 with a decreasing trend, similarly for wind speed and air temperature with an increasing trend. Moreover, the high value of sensitivity coefficients to relative humidity and wind speed was found in the first zone of study area, while the high value of sensitivity coefficients to solar radiation and air temperature was in fourth zone of south region. The findings from this research provide important information for crop planting adjustment, ecological engineering planning and water-soil resource management in 3H plain in an attempt to improving the healthy development of agriculture and ecological environment.