Causes of early Holocene desertification in arid central Asia

• DOI: 10.1007/s00382-011-1086-1
• Publication Date: 2011-05-11T13:30:14Z
• Authors: Liya Jin; Fahu Chen; Carrie Morrill; Bette L. Otto-Bli...; Nan Rosenbloom
• Keywords: Paleoclimatology; Westerlies; East Asian Monsoon; Meltwater; Holocene climatic optimum

Paleoclimate records of effective moisture (precipitation minus evaporation, or P–E) show a dry (low moisture) period in mid-latitude arid/semi-arid central Asia during the early Holocene (11,000–8,000 years ago) relative to middle and late Holocene, contrast evidence for greater-than-present precipitation at same time south east Asian monsoonal areas. To investigate spatial differences climate response over we conducted series simulations with Community Climate System Model version 3 coupled model early, Holocene. The test climatic impact all important forcings including changes orbital parameters, presence remnant Laurentide ice sheet deglacial freshening North Atlantic. results clearly patterns indicated by proxy records, both decreased arid Asia, which occurs primarily winter months, increase summer monsoon Asia. suggest that conditions are closely related water vapor advection due reduced westerly wind speed less evaporation upstream from Mediterranean, Black, Caspian Seas boreal winter. As an extra forcing system, meltwater fluxes have substantial cooling effect high latitudes, especially just downstream sheets, but contribute only small degree aridity Instead, most signal can be explained decreasing latitudinal temperature gradient wintertime surface temperature. We find little regional subsidence stronger as has been previously hypothesized.