Role of vegetation and soil in the Holocene megathermal climate over China

There was significant difference between vegetation cover in mid-Holocene and that at present over China based on various evidences as concluded by Shi et al [1992]. These changes were introduced to the climate model to study the role of the changing vegetation and associated soil to the simulated climate of mid-Holocene at 6000 years before present (BP) with bigger seasonal cycle of insolation than present (caused by the change of orbital parameters). Results show that the changes in vegetation and soil could further strengthen the monsoon rainfall over China. We found that replacing the today's seasonal cycle of insolation by that of mid-Holocene increases the summer (June-August) precipitation by 20% in eastern China(100 degrees-120 degrees E, 18 degrees-42 degrees N); while considering both the effect of changing orbital forcing and the vegetation and soil, the total summer precipitation increase is 29% in the same region. Compared with the reconstructed precipitation over China, the result of that including changing vegetation and soil is quantitatively better.