三峡蓄水对局地气候变化的影响

Impact of Water Storage in Three Gorges Reservoir on Local Climate Change

大型水体会对局部地区(局地)气候条件造成影响,三峡工程是当今世界规模最大的水利水电枢纽工程,为了分析三峡蓄水对当地气候变化的影响,以三峡库区10个站点为研究对象,利用气候倾向率、CVM检验等方法,系统分析了三峡库区66 a来气候变化特征以及蓄水对局地气候变化的影响。结果表明,三峡蓄水后局地温度下降,影响大坝附近299.83 km^(2)的地区,影响距离最远距大坝12.65 km,大坝最近的秭归站温度在1997年发生突变,蓄水后20 a秭归站年平均温度较蓄水前20 a下降1.15℃;蓄水造成局地降水量增加,影响大坝附近2914.88 km^(2)的地区,影响距离最远距大坝109.15 km,大坝最近的秭归站降水在1997年突变,蓄水后20 a秭归站平均降水量较蓄水前上升245.90 mm;蓄水造成局地相对湿度增加,秭归、兴山站相对湿度分别在1997年、2003年突变,蓄水后20 a秭归站相对湿度较蓄水前20 a上升5.29%;蓄水造成局地日照时数下降,影响大坝附近2045.66 km^(2)的地区,影响距离距大坝最远41.06 km,距大坝最近的秭归站日照时数在2002年突变,蓄水后20 a秭归站日照时数较蓄水前20 a下降33.87 h。蓄水对气象要素影响的范围较小,对各要素共同造成影响的范围仅75.27 km^(2),各要素全部在蓄水期间发生突变的仅秭归一站。

Due to special underlying surface properties,large water bodies have impacts on local water thermal cycle and climate.The Three Gorges Project is the world's largest water conservancy project.In the present research,we analyzed systematically the characteristics of climate change in the Three Gorges Reservoir over the past 66 years and the impacts of water storage on local climate by means of climate tendency rate and CVM test.Results demonstrated that the local temperature of the Three Gorges Project has declined after impoundment,affecting an area of 299.83 km^(2) near the dam,reaching 12.65 km away from the dam.The temperature of Zigui station,which is the closest to the dam,changed abruptly in 1997.The average annual temperature of Zigui two decades after the impoundment was 1.15℃lower than that before the impoundment.Local precipitation has increased,affecting an area of 2914.88 km^(2),reaching 109.15 km away from the dam.The precipitation of Zigui station also changed abruptly in 1997,and the average precipitation of Zigui two decades after the impoundment increased by 245.90 mm compared with that before the impoundment.Water storage also led to the rise of local relative humidity.Zigui and Xingshan witnessed abrupt changes in relative humidity in 1997 and 2003,respectively,of which the former rose by 5.29%two deades after the impoundment.The number of sunshine hours reduced,affecting the nearby area of 2045.66 km^(2),extending 41.06 km away from the dam.The sunshine hours of Zigui changed abruptly in 2002,reducing by 33.87 hours compared with that two decades before the impoundment.In conclusion,water storage in the Three Gorges Reservoir has had a small scope of influence on meteorological elements,affecting an area of only 75.27 km^(2) on all the elements;only Zigui station experienced abrupt changes in all the elements during water storage.