| 长江流域蒸发皿蒸发量的区域变化特征及影响因素 |
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| 引用本文： | 杨蓉华,李佳佳,贺新光.长江流域蒸发皿蒸发量的区域变化特征及影响因素[J].热带地理,2022,42(12):2098-2109. |
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| 作者姓名： | 杨蓉华 李佳佳 贺新光 |
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| 作者单位： | 1.湖南师范大学 地理科学学院，长沙 410081;2.地理空间大数据挖掘与应用湖南省重点实验室，长沙 410081 |
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| 基金项目： | 湖南省教育厅创新平台开放基金(18K018) |
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| 摘 要： | 基于长江流域148个气象站1980—2017年的蒸发皿观测数据，将旋转经验正交函数（REOF）和模糊C均值聚类（FCM）相结合，对流域蒸发皿蒸发量（PE）进行分区，然后运用Modified Mann-Kendall检验和多元逐步回归等方法，分析各子区域PE的变化特征并识别其主要影响因子。结果表明：1）REOF的前4个空间模态显示流域PE存在5个主要的异常敏感区，基于这4个空间模态，流域PE在空间上可划分为9个子区域。2）在年尺度上，各区PE呈不同程度的增加趋势，其中中部盆地区上升速率最大（111.28 mm/10 a），西部高原区上升速率最小（12.5 mm/10 a）；而在季节尺度上，秋、冬季流域PE呈显著上升趋势，春、夏季PE的变化具有明显的区域差异性，部分地区PE为下降趋势。3）影响PE变化的主要因子因地而异，但大多子区域的PE变化与平均气温和饱和水汽压差的变化显著相关。
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| 关 键 词： | 蒸发皿蒸发量 蒸发异常敏感区 气候倾向率 平均气温 饱和水汽压差 长江流域 |
| 收稿时间： | 2022-04-17 |
Analysis of Regional Variation Characteristics and Influencing Factors of Pan Evaporation in the Yangtze River Basin |
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| Ronghua Yang,Jiajia Li,Xinguang He.Analysis of Regional Variation Characteristics and Influencing Factors of Pan Evaporation in the Yangtze River Basin[J].Tropical Geography,2022,42(12):2098-2109. |
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| Authors: | Ronghua Yang Jiajia Li Xinguang He |
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| Institution: | 1.College of Geographic Science, Hunan Normal University, Changsha 410081, China;2.Key Laboratory of Geospatial Big Data Mining and Application, Hunan Province, Changsha 410081, China |
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| Abstract: | Evaporation is an important component of both hydrological and energy cycles and is very sensitive to climate change. In the context of global warming, rising temperature leads to a series of changes in hydrological factors, such as precipitation, evaporation, soil moisture, and groundwater flow, which have significant impacts on the natural environment, ecosystems, and social economy. Pan Evaporation (PE) is a vital climatic factor for estimating the atmospheric evaporation demand, and its change has been recognized as an integrative indicator of the hydrological response to climate change. Therefore, it is of great theoretical and practical significance to analyze the variation characteristics of PE and its influencing factors for water resource evaluation, hydrological process research, agricultural irrigation, and evaporation monitoring under climate change. The Yangtze River Basin (YRB) is a densely populated and highly developed area that plays an important role in the development of China's national economy. To discuss the variations in PE in the YRB and its main influencing factors, previous studies only divided the basin into upper, middle, and lower reaches based on natural and social factors. However, the area of the YRB is vast, and the PE varies greatly among the different regions of the basin under the influence of terrain and climate conditions. It is not sufficient to discuss the variation characteristics of regional PE from upstream, middle, and downstream. Additionally, most time series remained around 2000 in the existing studies, and the analysis of change characteristics of recent PE time series and its influencing factors have not been reported. Therefore, it is essential to conduct consistent regionalization for PE in the YRB and to identify the factors influencing PE variations in the subregions in recent decades. In this study, the Rotating Empirical Orthogonal Function (REOF) and Fuzzy C-Means clustering algorithm (FCM) were applied to form subregions based on pan observation data from 148 meteorological stations in the Yangtze River Basin during 1980-2017. Then, the variation characteristics and main influencing factors of PE in each sub-region were analyzed using the modified Mann-Kendall test and multivariate stepwise regression analysis. The results are as follows: (1) The first four REOF modes revealed five principal PE anomaly sensitive areas in the basin: southeast Poyang Lake plain, southwest Hengduan Mountain, northern Nanyang Basin, western Sichuan Plateau, and Central Sichuan Basin. Based on these spatial modes, the PE in the basin can be divided into nine subregions. (2) At the annual scale, PE in respective regions shows an increasing trend with the highest rate (111.28 mm/10 a) in the central basin and the lowest rate (12.5 mm/10 a) in the western plateau region. At the seasonal scale, PE in autumn and winter showed an increasing trend in the whole basin, while the variation in PE in spring and summer showed obvious regional differences, and PE in some areas showed a decreasing trend. (3) The main factors affecting the change in PE differ from region to region; however, in most of the sub-regions, PE variations are closely related to the changes in mean temperature and vapor pressure deficit. Our results are conducive to a better understanding of the temporal changes in PE in other regions of the world. In particular, the results can contribute to the development of more efficient methods for modeling and predicting PE variations by focusing on the main influencing factors under changing climatic conditions. |
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| Keywords: | Pan Evaporation evaporation anomaly sensitive areas climate tendency rate average air temperature vapor pressure deficit Yangtze River Basin |
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