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Another Record of Asian Monsoon Variability
Reference
Ji, J., Shen, J., Balsam, W., Chen, J., Liu, L. and Liu, X.  2005.  Asian monsoon oscillations in the northeastern Qinghai-Tibet Plateau since the late glacial as interpreted from visible reflectance of Qinghai Lake sediments.  Earth and Planetary Science Letters 233: 61-70.

What was done
The authors used reflectance spectroscopy on a sediment core taken from Qinghai Lake, located in the northeastern part of the Qinghai-Tibet Plateau, to obtain a continuous high-resolution proxy record of the Asian monsoon over the past 18,000 years.

What was learned
Monsoonal moisture since the late glacial period was shown to be subject to "continual and cyclic variations," among which was a "very abrupt onset and termination" of a 2,000-yr dry spell that started about 4200 yr BP and ended around 2300 yr BP.  Other variations included the well-known centennial-scale cold and dry spells of the Dark Ages Cold Period (DACP) and Little Ice Age (LIA), which lasted from 2100 yr BP to 1800 yr BP and 780 yr BP to 400 yr BP, respectively.  Sandwiched between them was the warmer and wetter Medieval Warm Period, while preceding the DACP was the Roman Warm Period.

Time series analysis of the sediment record revealed statistically significant periodicities (above the 95% level) of 123, 163, 200 and 293 yr, the 200-yr periodicity of which corresponds well with the de Vries or Suess solar cycle and implies that change in solar activity is an important trigger for some of the cyclic environmental changes at Qinghai Lake.

What it means
Once again we have another new study that indicates that large and abrupt fluctuations in the Asian monsoon have occurred with great regularity throughout the Holocene, and that the sun is an important factor driving some of these changes.  Given that they occur naturally, there is little reason to believe that any similar change that might occur in the near future would be in any way related to the anthropogenic-induced ongoing rise in the air's CO2 content; but you can be sure that the world's climate alarmists would make the new "monsoon regime shift" their catastrophic climate-change poster child in a heartbeat.

Reviewed 7 September 2005