Letters to Nature

Nature 411, 290-293 (17 May 2001) | doi:10.1038/35077048; Received 14 September 2000; Accepted 26 March 2001

Strong coherence between solar variability and the monsoon in Oman between 9 and 6 kyr ago

U. Neff1, S. J. Burns2,3, A. Mangini1, M. Mudelsee4, D. Fleitmann2 & A. Matter2

  1. Heidelberg Academy of Sciences, Im Neuenheimer Feld 229, Heidelberg, Germany D-69120
  2. Geological Institute, University of Bern, Baltzerstrasse 1, Bern, Switzerland CH-3012
  3. Institute of Meteorology, University of Leipzig, Stephanstrasse 3, Leipzig, Germany D-04103
  4. Present address: Department of Geosciences, University of Massachusetts, Amherst, Massachusetts 01003, USA.

Correspondence to: S. J. Burns2,3 Correspondence and requests for materials should be addressed to S.B. (e-mail: Email: sburns@geo.umass.edu).

Variations in the amount of solar radiation reaching the Earth are thought to influence climate, but the extent of this influence on timescales of millennia to decades is unclear. A number of climate records show correlations between solar cycles and climate1, but the absolute changes in solar intensity over the range of decades to millennia are small2 and the influence of solar flux on climate is not well established. The formation of stalagmites in northern Oman has recorded past northward shifts of the intertropical convergence zone3, whose northward migration stops near the southern shoreline of Arabia in the present climate4. Here we present a high-resolution record of oxygen isotope variations, for the period from 9.6 to 6.1 kyr before present, in a Th–U-dated stalagmite from Oman. The delta18O record from the stalagmite, which serves as a proxy for variations in the tropical circulation and monsoon rainfall, allows us to make a direct comparison of the delta18O record with the Delta14C record from tree rings5, which largely reflects changes in solar activity6, 7. The excellent correlation between the two records suggests that one of the primary controls on centennial- to decadal-scale changes in tropical rainfall and monsoon intensity during this time are variations in solar radiation.