Response of extreme precipitation events in the middle and lower reaches of the Yangtze River Basin to the atmospheric circulation based on continuous wavelet transform
Under the background of climate warming, thoroughly understanding extreme precipitation in response to the atmospheric circulation is of great importance to the prevention and management of regional flood disasters. Based on the daily precipitation data of 435 meteorological stations in the middle and lower reaches of the Yangtze River Basin from 1980 to 2018，we analyzed the extreme precipitation indices, the characteristics of oscillation period of the atmospheric circulation indices, and their common characteristics and correlations in time and frequency using cross wavelet transform and wavelet coherence methods based on continuous wavelet transform. The results showed that each extreme precipitation index had multi scale periodic oscillations, which mostly tended to be on high time frequency scales. This indicates that each extreme precipitation index experienced “increase-decrease” changes frequently during 1980-2018. Furthermore, each atmospheric circulation index had significant cycles from the mid 1980s to the mid 1990s. The interactions between atmospheric circulation and extreme precipitation indices were mainly reflected on the interannual scale, but there were obvious differences in time domains. In addition, EASM and PDO had a weaker impact on the extreme precipitation in the high energy spectrum region, while IOD had a weaker impact in the low energy spectral region.