Diagram of Winter Monsoon Winds
Click for larger image.
|
Influence of the intertropical convergence zone on the East Asian monsoon
Nature
Vol 445, Number 7123, pp. 74-77, 4 January 2007, doi:10.1038/nature05431.
Gergana Yancheva1, Norbert R. Nowaczyk1, Jens Mingram1, Peter Dulski1,
Georg Schettler1, Jörg F. W. Negendank1,
Jiaqi Liu2, Daniel M. Sigman3, Larry C. Peterson4 & Gerald H. Haug1
1 GeoForschungsZentrum (GFZ), Section 3.3, Telegrafenberg, Potsdam D-14473, Germany.
2 Institute of Geology and Geophysics, Chinese Academy of Sciences, PO Box 9825, Beijing
100029, China.
3 Department of Geosciences, Princeton University, Princeton, New Jersey 08544, USA
4 Rosenstiel School ofMarine and Atmospheric Science, University of Miami, Miami, Florida 33149, USA.
|
ABSTRACT:
The Asian-Australian monsoon is an important component of the Earth's
climate system that influences the societal and economic activity of
roughly half the world's population. The past strength of the rain-bearing
East Asian summer monsoon can be reconstructed with archives such as cave
deposits, but the winter monsoon has no such signature in the hydrological
cycle and has thus proved difficult to reconstruct. Here we present high-
resolution records of the magnetic properties and the titanium content
of the sediments of Lake Huguang Maar in coastal southeast China over the
past 16,000 years, which we use as proxies for the strength of the winter
monsoon winds. We find evidence for stronger winter monsoon winds before
the Bølling-Allerød warming, during the Younger Dryas episode and during
the middle and late Holocene, when cave stalagmites suggest weaker summer
monsoons. We conclude that this anticorrelation is best explained by
migrations in the intertropical convergence zone. Similar migrations of
the intertropical convergence zone have been observed in Central America
for the period AD 700 to 900, suggesting global climatic changes at that
time. From the coincidence in timing, we suggest that these migrations
in the tropical rain belt could have contributed to the declines of both
the Tang dynasty in China and the Classic Maya in Central America.
|