Indian summer monsoon drives synchronous interdecadal hydroclimate changes in the Tibetan Plateau and surroundings

Abstract

The interdecadal relationship (10–100 years) between the Indian Summer Monsoon (ISM) and arid climate is pivotal in comprehending Asian hydroclimate dynamics. Despite extensive tree-ring based climate reconstructions conducted across both monsoonal and arid regions in the Tibetan Plateau (TP) and surroundings, the correlation between the ISM and arid climate on interdecadal scales remains contentious. In this study, we assembled a tree-ring network from 242 moisture-sensitive sites around the TP. We established composite chronologies over three regions each in southern and northern TP, revealing more pronounced interdecadal fluctuations than those identified using traditional methods. These moisture-sensitive composite chronologies demonstrated synchronous variations on interdecadal timescales throughout their common period from 1517 to 2003, encompassing the most severe drought. The concurrent hydroclimate changes around the TP exhibited the strongest correlations with the ISM-dominated Himalayan region on interdecadal scales, signifying ISM-driven synchronous changes. Furthermore, the synchronous interdecadal hydroclimate changes displayed positive associations with solar irradiance. Notably, the driest periods coincided with the most intense solar Maunder Minimum (∼1645–1715) and Dalton Minimum (∼1790–1830), further underscoring the influence of solar activity on regional hydroclimate conditions.