Increased water vapor supply in winter and spring leading to the arid Central Asian wetting in last 6000 years  

作　　者：Xu ZHANG Bo LIU Shengqian CHEN Zhenhao FU Tingting XIE Fahu CHEN 

机构地区：[1]Key Laboratory of Western China's Environmental SystemsMinistry of Education,College of Earth and Environmental Sciences,Lanzhou University,Lanzhou 730000,China [2]Alpine Paleoecology and Human Adaption Group(ALPHA),State Key Laboratory of Tibetan Plateau Earth System,Resources and Environment(TPESRE),Institute of Tibetan Plateau Research,Chinese Academy of Science,Beijing 100101,China

出　　处：《Science China Earth Sciences》2022年第7期1353-1367,共15页中国科学（地球科学英文版）

基　　金：supported by the National Program on Key Basic Research Project of China(Grant No.2018YFA0606403)。

摘　　要：Paleoclimate reconstructions show that the arid Central Asia(ACA)is characterized by a wetting trend from the midHolocene(MH)to the Preindustrial period(PI),which has been acknowledged to be a result of increased mean precipitation.However,a systemic understanding of its governing dynamics remains elusive.Based on model outputs from 13 climate models from the Paleoclimate Model Intercomparison Project phase 4(PMIP4)and proxy records from ACA,here we show that increase in mean precipitation in ACA can be attributed to changes in water vapor source and its transport intensity in winter(December,January,and February)and spring(March,April,and May).In particular,the increase in water vapor supply in winter is associated with the southerly wind anomaly over the northwestern Indian Ocean and Central Asia,caused by an overall weakening of the Asian winter monsoon.This is conducive to water vapor transport from the upwind regions(e.g.,Mediterranean)to ACA.Meanwhile,water vapor supply from the eastern Iceland is also enhanced due to a negative North Atlantic Oscillation-like(NAO-like)atmospheric circulation pattern caused by sea ice expansion in the North Atlantic.In spring,evaporation over land and inland lakes is enhanced by increased insolation in the Northern Hemisphere,which increases atmospheric humidity that fuels midlatitude westerlies to enhance ACA precipitation.In addition,weakened atmospheric subsidence over ACA in winter and spring also contributes to the increased precipitation.Overall,our results indicate that paleoclimate modeling is of great importance for disentangling governing dynamics accounting for reconstructed climate phenomena that might be a synergic consequence of several processes operating in different seasons.

关 键 词：Arid Central Asia Precipitation MID-HOLOCENE Paleoclimate simulation 

分 类 号：P426.616[天文地球—大气科学及气象学]