A1B情景下东亚地区未来春季沙尘变化趋势预估

Prediction on Dust in Spring during 2015-2100 over East Asia under A1B Scenario

采用区域气候与沙尘耦合模式RegCM4-Dust,模拟研究了A1B情景下东亚地区未来(2015—2100年)春季沙尘变化趋势。结果表明:(1)总体上,东亚沙尘源区起尘通量与沉降通量存在明显的振荡特征,而沙尘光学厚度呈现显著的波动减小趋势;源区下游沙尘光学厚度和沉降通量均呈现显著的波动增大趋势。(2)沙尘子源区中,仅塔克拉玛干沙漠及周边地区起尘通量有显著波动减少趋势,速度达-2.1%/10a;萨雷耶西克阿特劳沙漠和呼伦贝尔沙地沙尘光学厚度减小速度最快,分别达到-2.8%/10a、-2.3%/10a。(3)未来,中国华北南部、黄淮以及长江中下游地区以及中国东、南部近海春季沙尘光学厚度增速均为1.5%/10a;中国近海沙尘沉降通量显著上升,速度达1.9%/10a。(4)地面风速尤其是最大风速变化是导致起尘通量变化的主要因素,而影响光学厚度的主要因素是地面最大风速。

A regional climate model RegCM4 coupled with an on-line dust module is used to predict the future trend of East Asian dust in spring from 2015 to 2100. Based on the simulation results, there generally exists obvious oscillation characteristics of the dust emission flux （DEF） and dust deposition flux （DDF）. The mod- el also captures the significant fluctuating and descending trend of the dust optical depth （DOD） over East A- sian dust sources. At the same time, the DOD and DDF appear significant fluctuating and ascending trend o- ver downstream areas of dust sources. Only the DEF over the Taklimakan Desert and its circumjacent areas presents significant fluctuating and descending trend over all East Asian dust sub-sources. The maximal fall- ing velocity of DOD occurs over Saryesik-Atyrau Desert and Hulun Buir Desert with the values up to --2.8%/10a and --2.3%/10a respectively. In addition, the rising velocity of DOD is 1.5%/10a over southern North China, Huanghuai Area, the middle and lower reaches of Yangtze River and eastern and southern Chinese offshore. The significant rise （1.9%/10a） of DDF may do harm to the marine environment of our country. Compared to the maximum surface wind speed for DOD, the mean surface wind speed especially maximum surface wind speed are the main factors of the DEF.