在气候变化的背景下，自上世纪80年代以来，我国水库修建、水生态文明建设等人类活动也日益剧烈，这带来的水体变化可能会加剧我国的水资源短缺。为了解我国不同区域水体变化特点和变化原因，进而为水资源管理与水生态文明建设提供科技支撑。这里根据气候特点、干湿状况、经济发展水平和人口密度等在全国范围内选取了9个研究区域，然后基于Google Earth Engine云计算平台在线调用Landsat卫星遥感影像并辅以DEM数据，采用多指数组合法并结合目视解译法提取了各个研究区在1985~2018年期间的各个季节的水体面积，并量化分析了各个研究区水体面积变化的原因；采用Penman-Monteith公式计算各个研究区的水面蒸发并定量分析了影响水体蒸发量变化的原因。其主要结果和结论为：

（1）人类活动与气候变化共同作用改变了中国水体面积

在1985~2018年期间，不同研究区的水体面积表现出不同的变化规律。半干旱半湿润地区的北京市、密云水库和半干旱地区红碱淖的水体面积明显减少；半湿润地区的徐州市的水体面积有所增加；位于高寒山区的纳木错的水体面积明显增加。人类活动对不同研究区的作用程度和作用方向不同，干旱半干旱区抵抗人类活动干扰的能力弱，人类活动（水景观、水利工程等）对水体影响程度较大，既可能造成天然水面的减少（红碱淖），又可能造成人工水面的增加（乌海市）；湿润区抵抗人类活动干扰的能力强，一定程度的人类干扰对水面变化产生的影响不大（广州市、鄱阳湖）；像纳木错这种人类活动较少的地区，水体面积主要随气候变化而变化。

（2）我国不同地区蒸发能力变化表现不同特征

年蒸发能力呈现增加趋势的有广州市、徐州市、红碱淖、纳木错和鄱阳湖，其中呈现显著增加的有广州市和红碱淖，广州市的年蒸发能力增加速率为1.5mm/yr，红碱淖的年蒸发能力增加速率为7.2mm/yr；年蒸发能力呈现减少趋势的有北京市、乌海市、白洋淀和密云水库，其中乌海市、白洋淀和密云水库呈现显著减少趋势，乌海市的年蒸发能力减少速率为1.9mm/yr，白洋淀的年蒸发能力减少速率为1.7mm/yr，密云水库的年蒸发能力减少速率为2.9mm/yr。

（3）我国不同地区水体蒸发量变化各异

各个研究区域的水体蒸发量都遵循“春夏季多，秋冬季少”的季节性变化规律；在1986~2018年期间，年水体蒸发量呈现增加现象的有广州市、徐州市、乌海市、纳木错和鄱阳湖，其中徐州市的年水体蒸发量增加速率为0.042×10⁸m³/yr，乌海市的为0.024×10⁸m³/yr，纳木错的为0.049×10⁸m³/yr，鄱阳湖的为0.051×10⁸m³/yr；年水体蒸发量呈现减少现象的有北京市、白洋淀、红碱淖和密云水库，其中北京市的年水体蒸发量减少速率为0.011×10⁸m³/yr，白洋淀的年水体蒸发量减少速率为0.010×10⁸m³/yr，红碱淖的年水体蒸发量减少速率为0.005×10⁸m³/yr。

（4）水体面积发生变化较大是导致水体蒸发量变化主要原因

除纳木错之外的其它研究区，蒸发能力变化对水体蒸发量变化的影响都比较小，水体蒸发量变化都主要是由水体面积变化引起的，且不同的研究区域水体面积变化对水体蒸发量变化的作用方向不同，对水体蒸发量变化起正向影响的主要有徐州市、乌海市和鄱阳湖，对应的水体面积变化的贡献率分别为99.71%、97.90%和75.83%；对水体蒸发量变化起负向影响的主要是北京市、广州市、白洋淀、红碱淖和密云水库，对应的水体面积变化的贡献率分别为-92.03%、-78.26%、-97.14%、-73.27%和-86.10%。对于半干旱半湿润且人口密集的区域，像乌海市、白洋淀，其水体面积增大造成的无效蒸发损失可能会加剧水资源短缺问题。

In the context of climate change, since the 1980s, human activities such as the construction of reservoirs and the construction of aquatic ecological civilization in China have become increasingly fierce. Changes in water bodies brought about by this may exacerbate water shortage. In order to understand the characteristics and causes of changes in water bodies in different regions of China, and then provide scientific and technological support for water resources management and the construction of aquatic ecological civilization. Here, nine research areas were selected nationwide based on climatic characteristics, wet and dry conditions, economic development level, and population density. Then, online Landsat satellite remote sensing image was invoked, supplemented by DEM data, based on the cloud computing platform of Google Earth Engine. Multiple indexes were used. Combined with the visual interpretation method, the water area of each study area in each season from 1985 to 2018 was extracted, and the reasons for the change of water area in each study area were analyzed quantitatively. The Penman-Monteith formula was used to calculate the water area of each study area. Water surface evaporation and quantitative analysis of the reasons affecting the change of water evaporation. The main results and conclusions are:

(1) Characteristics and causes of changes in water area

During the period of 1985~2018, the change of water area in different study areas was also different. Water areas in Beijing, Miyun Reservoir, and Hongjiannao Lake located in arid and semi-arid areas have decreased significantly; Water areas in Xuzhou, located in humid areas, have increased; Water areas in Namco, located in alpine mountains have increased significantly. Human activities play different roles in different research fields. The arid and semi-arid areas have weak ability to resist human interference, and human activities (water landscape, water conservancy projects) have a greater impact on water bodies, which may cause natural water surface reduction ( Hongjiannao Lake), which may also cause an increase in artificial water surface (Wuhai); The humid area has a strong ability to resist human interference, and a certain degree of human interference has little impact on water surface changes (Guangzhou, Poyang Lake); In areas with less human activities, water body changes with climate change(Namco).

(2) Changes in evaporation capacity

Guangzhou, Xuzhou, Hongjiannao Lake, Namco and Poyang Lake have an increasing annual evaporation capacity. Guangzhou and Hongjiannao Lake have a significant increase. The rate of increase of annual evaporation capacity in Guangzhou is 1.5mm / yr, 7.2mm / yr in Hongjiannao Lake; Beijing, Wuhai, Baiyangdian, and Miyun Reservoir are showing a decreasing annual evaporation capacity. Wuhai, Baiyangdian, and Miyun Reservoir are showing a significant decrease. The decrease rate of annual evaporation capacity in Wuhai is 1.9mm / yr, 1.7mm / yr in Baiyangdian, 2.9mm / yr in Miyun Reservoir.

(3) Variation characteristics of water evaporation

Water evaporation in each study area follows the seasonal change pattern of "more in spring and summer and less in autumn and winter". From 1986 to 2018, the annual water evaporation increased in Guangzhou, Xuzhou, Wuhai, Namco and Poyang Lake. The annual increase rate of water evaporation is 0.042 × 10⁸m³ / yr in Xuzhou, 0.024 × 10⁸m³ / yr in Wuhai, 0.049 × 10⁸m³ / yr in Namco, and 0.051 × 10⁸m³ / yr in Poyang Lake. The annual water evaporation decreased in Beijing, Baiyangdian, Hongjiannao Lake and Miyun Reservoir, the annual water evaporation reduction rate is 0.011 × 10⁸m³ / yr in Beijing, 0.010 × 10⁸m³ / yr in Baiyangdian, and 0.005 × 10⁸m³ / yr in Hongjiannao Lake.

(4) Reasons for changes in water evaporation

In other research areas except Namco, the effects of changes in evaporation capacity on changes in water evaporation are relatively small. Changes in water evaporation are mainly caused by changes in water area, and changes in water area in different study areas affect changes in water evaporation in different directions, the positive influences on water evaporation in Xuzhou, Wuhai, and Poyang Lake, and the corresponding contribution rates of water area changes are 99.71%, 97.90% and 75.83%, respectively; the negative influences on water evaporation in Beijing, Guangzhou, Baiyangdian, Hongjianyan Lake and Miyun Reservoir, the corresponding contribution rates of water area changes are -92.03%, -78.26%, -97.14%, -73.27%, and -86.10%. For arid and densely populated areas, such as Wuhai and Baiyangdian, the inefficient evaporation loss caused by the increase in water area may aggravate the shortage of water resources.