Analysis of the Spatiotemporal Variations in Heavy Rainfall Events in the Taihang Moutainous Region from 1973 to 2022

Based on the daily precipitation data from 13 meteorological stations in the Taihang moutainous region(TMR) spanning 50 a period, various methods such as the Mann-Kendall abrupt change test, the signal-to-noise ratio test, the Sen’s slope estimator, the wavelet analysis and the empirical orthogonal function decomposition, were applied to examine the spatiotemporal patterns of heavy rainfall events in the TMR. The findings revealed: (1) Heavy rainfall in the TMR showed the substantial fluctuation. According to the fitted slope and Sen’s slope estimation method, it was suggested that heavy rainfall in this region would experience an increasing trend in the future. (2) The Mann-Kendall abrupt change test and signal-to-noise ratio test indicated a notable transition towards higher levels of heavy rainfall in the TMR in 2006. (3) The Morlet wavelet analysis showed cyclic variations in heavy rainfall with period scales of 2~3 a in the study area. (4) The first two modes of the Empirical Orthogonal Function(EOF) analysis illustrated coherent spatial patterns throughout the entire region in heavy rainfall distribution, including a southwest-northeast reverse pattern. Both patterns were influenced by atmospheric circulation and topography in the TMR.