HR: 10:20h
AN: GP22A-01 INVITED     [Abstracts]
TI: On the interpretation of Chinese loess as a paleoclimate indicator
AU: * Roe, G
EM: gerard@ess.washington.edu
AF: University of Washington, 070 Johnson Hall, Seattle, Wa 98195, United States
AB: The records of wind blown dust, or loess, in China and elsewhere are some of the most important terrestrial records of past climate changes, stretching back over the last ten million years. In the paleoclimate literature, intervals of increased dust generation have been almost always interpreted as being associated with more intense or prolonged wintertime conditions. Here we show that, in accordance with modern observations, dust outbreaks in Asia are predominantly springtime phenomena. During spring, frequent cyclogenesis in the lee of the Mongolian Altai, and the passage of strong cold fronts produce the intense windstorms that loft and entrain dust into the air. The meteorology governing such outbreaks is likely to be robust in past climates. Contrary to the common paleoclimate presumption, it is actually the breakdown of the Siberian High that permits the dust- producing windstorms to occur. The importance of cold fonts in generating such windstorms suggests that cooling of high latitude climate over the Miocene, or during glacial intervals, might play a significant role in the signal recorded in the loess deposits.
DE: 0305 Aerosols and particles (0345, 4801, 4906)
DE: 3319 General circulation (1223)
DE: 3329 Mesoscale meteorology
DE: 4906 Aerosols (0305, 4801)
DE: 4914 Continental climate records
SC: Geomagnetism and Paleomagnetism [GP]
MN: 2007 Joint Assembly