Australia: The Land Where Time Began

A biography of the Australian continent 

North Atlantic Stadials Linked to Failure of the Deglacial Indian Monsoon by Surface Cooling in the Indian Ocean

The Indian monsoon, which is the largest monsoon system on Earth, has been found to respond to remote climate forcings, which include changes of temperature in the North Atlantic (Overpeck et al., 1996; Schulz, et al.). During 2 cool periods that punctuated the last deglaciation, Heinrich Stadial 1 and the Younger Dryas the monsoon was weak. Sea surface cooling in the Indian Ocean has been suggested to be the critical link between these North Atlantic stadials and the failure of the monsoon (Pausata et al., 2011); it is not clear however, based on existing proxy records (Saraswat et al., 2013), whether surface temperatures in the Indian Ocean and Arabian Sea dropped during these intervals. In this paper Tierney et al. compile new and existing data from the Arabian Sea which suggests that during both the Heinrich Stadial 1 and the Younger Dryas the surface temperatures cooled though the subsurface temperatures warmed. It was shown by analysis by Tierney et al. of model simulations that surface cooling weakens the monsoon winds which leads to destratification of the water column and substantial warming of the surface. Therefore Tierney et al. conclude that in the Indian Ocean the sea surface temperature does indeed link the climate of the North Atlantic to the strength of the Indian monsoon.

Sources & Further reading

1. Tierney, J. E., F. S. R. Pausata and P. deMenocal (2016). "Deglacial Indian monsoon failure and North Atlantic stadials linked by Indian Ocean surface cooling." Nature Geosci 9(1): 46-50.