SIMULATIONS OF EAST ASIAN CLIMATE AT 6kaB.P.
6kaB.P.东亚区域气候模拟及其变化机制探讨

Using a regional climate model with detailed land surface processes, East Asian monsoon climate at 6kaB.P. is simulated by employing the present day vegetation and the paleovegetation converted from the pollen records in the East Asia region, and the impact of the changes in vegetation on East Asian climate is investigated as well. The climatic evolution figures with a higher resolution obtained from the regional climate simulations show that the enlargement of the seasonal cycle of insolation, the reducing of perpetual snow and sea ice in high latitudes, and the increasing of polar sea temperature at 6kaB.P. led to the weakening of winter continental anticyclones and hence the diminishing of the amplitude of winter temperature decline in China; by the inclusion of paleovegetation in simulation, the surface albedo was reduced, thus further increasing in the winter temperature. This result not only made a break through the limitation of the winter temperature decline (compared with the present) obtained from many simulations of Paleoclimate Modeling Intercomparison Project (PMIP), but also renders the seasonal characters of simulated temperature changes in a better agreement with the geological records. The temperature rise in whole year during the 6kaB.P. over the East Asian continent resulted in the strengthening of the East Asian summer monsoon and the weakening of the winter monsoon; the precipitation and effective precipitation increased, and the monsoon rain belt spread westwards and northwards.$$