Ring Ring

Scientists from the Tree-Ring Laboratory at Columbia University's Lamont Doherty Earth Observatory have compiled tree-ring data from 327 sites in Asia into a new database called the Monsoon Asia Drought Atlas. The tree-rings date back to 1300 AD, which allowed the researchers to put together a year-by-year history of the region's monsoon rains and gives them good weather data for testing climate change models. The sites themselves are necessarily clumped in regions that contain old trees, but these data were used to extrapolate to regions which had no records available. The team mapped annual rainfall across Asia including the Indian and Australian monsoon areas and correlated rainfall patterns with 150 years of sea-surface-temperature recordings to look at how distant ocean conditions affect Asian weather. This is important because monsoons pull moisture from the ocean as hot air rises over the land mass. Looking at historical data will tell us if the drivers of these phenomena are the same now as in the past and to what degree global warming plays in altering these patterns. These data have revealed that past droughts were much longer and more severe than they are in modern times. But, at this point, the analysis has not yielded a lot of climate change model results but has great potential in this respect and will be used as a data source for many modelers.

Read more here: http://www.nature.com/news/2010/100422/full/news.2010.196.html

The journal article:

Edward R. Cook, et al. (2010) Asian Monsoon Failure and Megadrought During the Last Millennium. Science: 328 (5977), 486. (DOI: 10.1126/science.1185188)

and related to it:

Buckleya, Brendan M., et al. (2010) Climate as a contributing factor in the demise of Angkor, Cambodia. PNAS: 107 (15), 6748-6752. (DOI: 10.1073/pnas.0910827107)

(image from newsimg.bbc.co.uk/media/images)