| 摘要: |
| 为探究淡水湖库及其所属流域蒸散发演变特征，以及气象因子对蒸散发的影响规律。以长三角地区最大的淡水人工湖和重要的水源地——千岛湖为研究对象，采用Penman-Monteith等方法与WEP-L分布式水文模型，分别计算千岛湖流域1960-2020年潜在蒸散发ET_0与实际蒸散发ET_a，分析二者年际变化趋势及突变年份；采用偏微分方法分析气象因子对ET_0的敏感性和贡献度；采用归因分析法分析突变前后气象因子对ET_a变化的贡献度，并利用蒸发表面水分指数E_MI解析流域蒸发互补关系。结果表明：ET_0与ET_a多年平均值分别为1021.7mm和857.5mm，整体皆呈减少趋势，倾向率分别为-0.77mm/a、-1.03mm/a，二者均在1980年和2000年左右发生突变；ET_0对相对湿度变化最为敏感，ET_0增加的月份主要是由于相对湿度、平均气温的正贡献，风速呈负贡献但相对较小，ET_0减少的月份主要是由于日照时数和风速的负贡献，平均气温呈正贡献但相对较小；ET_a空间分布呈现东高西低格局，驱动因素按贡献率大小依次为相对湿度、风速、日照时数和气温；流域整体存在“蒸发悖论”现象，日照时数和风速的减小是引起ET_0近年来下降的主要原因；E_MI愈趋近于1时，反映流域ET_0和ET_a取值愈加接近，蒸散发互补理论在千岛湖流域适用。 |
| 关键词: 流域蒸散发 气候变化 互补关系 千岛湖 |
| DOI： |
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| 基金项目:国家自然科学基金资助项目（52279030）；国家重点研发计划资助项目（2021YFC3201101，2021YFC3201105） |
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| Evolution characteristics and influencing factors of evapotranspiration in Qiandao Lake Basin from 1960 to 2020 |
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DONG Hao1, DU Junkai1, YU Fakang2, QIU Yaqin1, LYU Xianglin1
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1.China Institute of Water Resources and Hydropower Research;2.Chun''an County Ecological Comprehensive Protection Bureau
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| Abstract: |
| The largest freshwater artificial lake and important water source in the Yangtze River Delta region, Lake Qiandao, was chosen as the research region to explore the evolvement characteristics of evapotranspiration in freshwater lakes and their watersheds, as well as the influence of meteorological elements on evapotranspiration. The Penman-Monteith method and WEP-L distributed hydrological model were employed to calculate the potential evapotranspiration (ET_0) and actual evapotranspiration (ET_a) in the Lake Qiandao basin from 1960 to 2020. The annual variations and mutation years of both ET_0 and ET_a were analyzed. The sensitivity and contribution of meteorological elements to ET_0 were analyzed using the partial derivative method. The contribution of meteorological elements to the change in ET_a before and after the mutation was analyzed using the attribution analysis method. Additionally, the evaporative surface water index E_MI was used to analyze the complementarity of basin evapotranspiration. The results showed that the multi-year average values of ET_0 and ET_a were 1021.7 and 857.5 mm, respectively, both exhibiting decreasing trends with inclination rates of -0.77 and -1.03 mm/a. Both ET_0 and ET_a experienced mutations around 1980 and 2000. Relative humidity had the highest sensitivity to ET_0 changes, and ET_0 increased mainly due to positive contributions from relative humidity and average temperature, with wind speed making a relatively small negative contribution. ET_0 decreased mainly due to negative contributions from sunshine duration and wind speed, with average temperature making a relatively small positive contribution. The spatial distribution of ET_a showed an east-high and west-low pattern, with the driving factors in order of contribution rate being relative humidity, wind speed, sunshine duration, and temperature. The basin exhibited an "evaporation paradox," and the reduction in sunshine duration and wind speed were the main reasons for the recent decline in ET_0. As E_MI approaches 1, it indicated that ET_0 and ET_a values in the basin were getting closer, and the theory of evapotranspiration complementarity was applicable in the Lake Qiandao basin. |
| Key words: Watershed evapotranspiration climate change complementary relationship Lake Qiandao |
