Abstract
Solar forcing exerts a notable influence on driving variability in monsoon patterns. However, the connection between decadal shifts in monsoon precipitation patterns and solar cycles remains ambiguous. This study delves into assessing the impact of the 11-year solar cycle on precipitation patterns during the East Asian summer monsoon (EASM) spanning from 1958 to 2020. Results indicate that the summer precipitation pattern on a decadal timescale, characterized by reverse variations in northern and southern China, can be attributed to the solar precipitation regime. The solar precipitation regime, intricately tied to the East Asia/Pacific (EAP) teleconnection, is impacted by zonal winds and convections in the western Pacific. In early summer, the EAP teleconnection is partially influenced by the solar signal in the stratosphere. During high solar years, the stratospheric ozone's heating response to solar radiation induces a warm anomaly in the tropical and subtropical lower stratosphere. This anomaly initiates anomalous convection in the troposphere, reinforcing the tropospheric EAP teleconnection and causing a northward shift in the rain belt. Additionally, the warm anomaly intensifies mid-latitude westerly winds in the lower stratosphere and upper troposphere, facilitating the downward propagation of signals and bolstering the EAP teleconnection. Consequently, the EAP teleconnection amplifies solar signals in the EASM region, fostering droughts in southern China and flooding in northern China during high solar years. These findings propose a mechanism through which the sun shapes the spatial pattern of precipitation and enhance our understanding of decadal variability of monsoon precipitation.
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