Spatiotemporal variations of precipitation and driving forces during wheat maturation season in Henan Province

Since entering the twenty-first century, global warming has continued to escalate, and the frequency of rainfall occurrence during the wheat maturity period has increased significantly, which has seriously threatened the yield of wheat. In this study, based on the rainfall data and a variety of remote correlation factors during the wheat maturation period in Henan Province from 2000 to 2022, we comprehensively explored the spatial and temporal characteristics of wheat maturation rain and its drivers in Henan Province by using the Pettitt method, the Morlet wavelet method, the center of gravity model, and cross-wavelets. The results show that: (1) the wheat maturation rain in Henan Province shows an upward trend, the mutation point is mainly concentrated in 2013, and the cycle change is characterized by a small scale; (2) The multi-year averages of total rainfall, maximum daily rainfall and rainfall intensity in the southern part of Henan Province during the wheat-yellow period were all the highest, and the number of rainfall days also showed a significant upward trend; (3) In 2013 wheat maturation rain in Henan Province, the center of gravity of daily rainfall was mainly concentrated in northwestern Henan Province, and the typical rainfall event mainly experienced five processes of occurrence-intensification-dissipation-re-intensification-dissipation; (4) Total rainfall, maximum daily rainfall and rainfall intensity had the highest correlation with sunspot, and overall sunspot had the greatest impact on wheat maturation rain. By analyzing the spatial and temporal characteristics of wheat maturation rain and further revealing its driving mechanism, it is of great significance to understand the ability of wheat to adapt to climate change and ensure food security.