东亚地区矿物尘气溶胶直接辐射强迫的初步模拟研究

A preliminary simulation study of direct radiative forcing of mineral dust aerosol over the East Asia region

为研究东亚地区矿物尘气溶胶的直接辐射效应,在区域气候模式RegCM3中加入起尘方案、建立矿物尘气溶胶输送模式,并将其辐射过程加入区域气候模式的辐射方案.通过对2001年3月～2002年3月的模拟发现:中国西北和蒙古国年平均地表起尘率在1μg/(m2·s)以上,最大达到90μg/(m2·s)是东亚地区最主要的矿物尘气溶胶源地;东亚地区矿物尘气溶胶柱含量最大值达5g/m2,出现在塔克拉玛干沙漠和秦岭地区;气溶胶大气顶直接辐射强迫基本呈现大陆上为正、海洋上正负均有的分布特征,区域平均辐射强迫在春夏秋冬分别为1.08,0.88,0.37,0.40W/m2,短波辐射强迫在陆上为正、海上正负均有,长波辐射强迫均为正值;四季的地表辐射强迫分别为-5.64,-2.25,-1.37,-1.87W/m2;辐射强迫数值对矿物尘气溶胶单次散射反照率的变化较敏感.

To study the direct radiative effect of dust aerosol over the East Asia region, a dust emission scheme, a transport model and a radiative scheme of dust aerosol have been added into the Regional Climate Model Version 3（RegCM3）. Based on the simulation for the period from March 2001 to February 2002, it has been found that Northwest China and Mongolia are the main dust sources in East Asia, whose emission rates at TOA is positive over land and negative or positive over sea, and its regional average values in Spring, Summer, Autumn, and Winter are 1.08, 0.88, 0.37, 0.40W/m^2 , respectively. The solar radiative forcing is also positive over land and negative or positive over sea, but the infrared radiative forcing is positive in the modeling region. The radiative forcing values at the surface for four seasons are - 5.64, - 2.25, - 1.37, - 1.87W/m^2 , respectively. Radiative forcing is affected sensitively by the change of single scattering albedo of dust aerosol.