Analysis of climate change in the middle reaches of the Yangtze River Basin using principal component analysis

Global warming and associated frequent extreme hydrological events with increasingly severe climate change threaten human life and economic development. Consequently, climate change has become a significant focus of the scientific community. The middle reaches of the Yangtze River Basin (MYRB) contain abundant water resources and is an area with intensive human activities; it is not only the center of social and economic development in China but also the region with the highest frequency of drought and flood disasters. This study analyzed the spatiotemporal characteristics of several climate change indicators, including temperature, precipitation, and the standardized precipitation evapotranspiration index (SPEI), in the MYRB during 1961–2017, using principal component analysis (PCA). The main results are as follows: (1) mean temperature, monthly air temperature sum, precipitation sum, maximum daily precipitation, and number of days with precipitation exceeding 30 mm were the primary variables that experienced variations in the MYRB; (2) the average temperature during spring and autumn and precipitation intensity in summer increased significantly in the MYRB, primarily in the east and the north. Increased aridity during spring, autumn, and winter was apparent in the MYRB; and (3) changes in the distribution of temperature and the intensification of drought were the principal variables that changed across the study period in the Hanjiang River Basin, while the dominant variables in Dongting Lake Basin and Yichang to Hukou Basin were precipitation regime and temperature-related indicators. The results of this study can improve our understanding of how climate change affects the MYRB, allowing the development of mitigation measures for meteorological disasters.