Centennial-scale linkages between the Indian Summer Monsoon and the solar irradiation from the Gulf of Khambhat (Western India)

The Indian Summer Monsoon (ISM) is a major driver of the summer precipitation across the Indian subcontinent affecting a vast population. Yet, the limited chronological extent of the instrumental records accompanied with the control of the climatic variables on the ISM, has hampered the efforts to document the climate change for the last two millennia. The present multiproxy study reports a high-resolution sedimentary record from the Gulf of Khambhat region (Western India) which represents two alternating climatic phases representing relatively arid and humid climatic conditions that coincides with the widely reported Dark Ages Cold Period (DACP) (AD 680 - AD 920) and Medieval Warm Period (MWP) (AD 920 to similar to AD 1400). This variability of the ISM, further tends to be modulated by the solar forcings, with the periods of solar minima coinciding well with the episodes of the reduced monsoonal strength and vice-versa. The difference in timing of DACP and MWP in the North Atlantic Region (NAR) and the present study, hints at the linkage between the ISM and NAR via an atmospheric route, driven by the solar variability.

Automated summary

The study provides a multi-proxy analysis of the Indian summer monsoon and climate change, finding that solar activity plays a significant role in modulating the monsoon strength and suggests a potential linkage with the North Atlantic region.