Spatiotemporal Distribution Characteristics and Influencing Factors Analysis of Reference Evapotranspiration in Beijing–Tianjin–Hebei Region from 1990 to 2019 under Climate Change

Reference evapotranspiration (ET0) is an important part of the water and energy cycles during crop growth. Understanding influencing factors spatiotemporal variations ET0 positive significance for guiding regional water-saving irrigation regulating agricultural production. Data daily meteorological observations temperature, relative humidity, wind speed, sunshine hours from 40 surface stations methods climate tendency rate, Morlet wavelet, M-K mutation, path analysis, sensitivity contribution rate analysis were utilized, to analyze distribution characteristics in Beijing–Tianjin–Hebei region 1990 2019. The 2019 was 958.9 mm, there a significant downward trend −3.07 mm/10 a. presents spatial pattern decreasing southwest northeast. A change region’s interannual occurred 2016, with decrease 41.12 mm since then. positively correlated hours, negatively humidity; among those, speed temperature are dominant affecting ET0. This study provides scientific basis regulation control production region.