Strong coherence between solar variability and the monsoon in Oman between9 and 6 kyr ago

Variations in the amount of solar radiation reaching the Earth are thought to influence climate, but the extent of this influence on timescales of mil lennia to decades is unclear. A number of climate records show correlations between solar cycles and climate(1), but the absolute changes in solar int ensity over the range of decades to millennia are small(2) and the influenc e of solar flux on climate is not well established. The formation of stalag mites in northern Oman has recorded past northward shifts of the intertropi cal convergence zone(3), whose northward migration stops near the southern shoreline of Arabia in the present climate(4). Here we present a high-resol ution record of oxygen isotope variations, for the period from 9.6 to 6.1 k yr before present, in a Th-U-dated stalagmite from Oman. The delta O-18 rec ord from the stalagmite, which serves as a proxy for variations in the trop ical circulation and monsoon rainfall, allows us to make a direct compariso n of the delta O-18 record with the Delta C-14 record from tree rings(5), w hich largely reflects changes in solar activity(6,7). The excellent correla tion between the two records suggests that one of the primary controls on c entennial- to decadal-scale changes in tropical rainfall and monsoon intens ity during this time are variations in solar radiation.