山东省降水量、潜在蒸散量与湿润指数的时空分布

Spatio-temporal Variation in Precipitation,Potential Evapotranspiration,Humidity Index in Shandong Province

【目的】分析山东省降水量、潜在蒸散量和湿润指数的长期时空分布特征及其影响因素,为农业水资源管理与水土保持等提供数据支持与决策依据。【方法】基于山东省20个气象站1966-2015年的气象数据资料研究了年均降水量、潜在蒸散量和湿润指数的空间分布特征,并采用主成分分析和相关分析法研究了与地理位置(经纬度)、海拔和相关气象因素的关系。在此基础上,由东南至西北选择日照、济南和陵县3个代表性站点分析了年降水量、潜在蒸散量和湿润指数1966-2015年的时间变化特征及其影响因素的地域性差异。【结果】山东省年均降水量自东南向西北减少而潜在蒸散量升高,年均湿润指数介于0.43~0.89之间,半干旱区和半湿润区面积分别占28.7%和71.3%;主成分分析表明,第一、二主成分主要与海拔、气温相关因子和相对湿度有关,可解释超过70%的环境因子变异,年均降水量的空间分布与海拔和气温相关性高,而年均潜在蒸散量主要受相对湿度的变化影响;1966-2015年各站点年降水量和湿润指数与时间的相关性不显著,而年潜在蒸散量的变化趋势存在明显的地域性差异;在日照由于平均气温升高和风速降低,导致辐射项升高,年潜在蒸散量呈上升趋势,而在陵县由于相对湿度升高导致空气动力学项降低幅度超过辐射项升高幅度,导致年潜在蒸散量呈降低趋势。【结论】山东省降水量、潜在蒸散量和湿润指数的空间分布受地理位置、地形和环境因素的综合影响,1966-2015年的时间变化特征及其影响因素具有显著的地域性差异。

【Background】Water resource distribution varies spatially and temporally and the imbalance between water availability and demand has become limiting factors to sustainable socioeconomic development in China.【Objective】The purpose of this paper is to analyze the long-term spatiotemporal variation in precipitation,potential evapotranspiration and humidity index in Shandong province aimed to provide a database for improving agricultural water resource management and soil and water conservation in this region.【Method】The analysis was based on meteorological data measured from 20 meteorological stations across the province in 1966-2015,from which we calculated spatial distributions of the mean annual precipitation,the potential evapotranspiration and the humidity index.We also analyzed their relationship based on their geographical location(latitude and longitude),elevation,and climatic factors.Three stations representing typical weather change from the southeast to the northwest of the province were selected to elucidate the temporal variation in annual precipitation,potential evapotranspiration and humidity index,as well as their determinants across the province.【Result】The mean annual precipitation decreased from the southeast to the northwest while the mean annual potential evapotranspiration trended in opposite direction across the province.The mean annual humidity index varied between 0.43~0.89,with the semi-arid zone and semi-humid zones accounting for 28.7%and 71.3%of the total area in the province respectively.Principal component analysis showed that the Axis 1 and Axis 2 explained over 70%of the variations in environments,which were highly correlated with elevation,temperature and relative humidity.The spatial distribution of mean annual precipitation correlated highly with the elevation and temperature,while the mean annual potential evapotranspiration was mainly affected by relative humidity.From 1966 to 2015,the annual precipitation and humidity index at the three stations did not show a temporal trend at significant level,while there was a substantial difference in temporal trend of the annual potential evapotranspiration between the three stations.At the Rizhao station,the aerodynamic term in the potential evapotranspiration had increased at significant level due to the increase in temperature and decrease in wind speed,which resulted in an increase in annual potential evapotranspiration.At the Lingxian station,the decline in the radiation term offset the increase in the aerodynamic term because of the increase in relative humidity,which led to a reduction in annual potential evapotranspiration.【Conclusion】The spatial distribution of precipitation,potential evapotranspiration and humidity index all depended on the combined impacts of geographic location,topographic and climatic factors,and the temporal variation in these indicators and their correlation with other climatic factors differed spatially across the province at significant level.These findings are helpful for analyzing and balancing water supply and demand to achieve sustainable water resource management in the province.