Simulation of dust aerosol radiative feedback using the GMOD: 2. Dust-climate interactions
Simulation of dust aerosol radiative feedback using the GMOD: 2. Dust-climate interactions
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DOI：
10.1029/2009jd012063
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发表时间：
2010-02
影响因子：
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通讯作者：
X. Yue;Huijun Wang;H. Liao;K. Fan
中科院分区：
文献类型：
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作者：
X. Yue;Huijun Wang;H. Liao;K. Fan
[1]我们利用嵌入在一个大气环流模式（GCM）中的全球沙尘输送模式（GMOD），研究了沙尘气溶胶的短波和/或长波直接辐射效应对气候平衡的影响。据估计，大气中沙尘气溶胶的存在对大气顶部（TOA）的全球平均短波和长波辐射强迫（RF）分别为 -0.25瓦/平方米和 +0.27瓦/平方米，对地表则分别为 -1.95瓦/平方米和 +0.61瓦/平方米。我们使用两种不同的方法模拟沙尘的气候效应。在第一种方法中，先验模拟的沙尘月平均场被用于GCM的辐射传输模块以驱动气候变化，在气候积分过程中沙尘含量固定（记为FIXDST模拟）。在第二种方法中，沙尘气溶胶通过沙尘循环及其直接辐射效应与气象学进行在线相互作用（记为CPLD模拟）。考虑沙尘的长波和短波辐射强迫，在FIXDST中，全球和年平均地表气温以及200百帕高度的气温预测变化分别为0和 +0.12开尔文，在CPLD模拟中则分别为 -0.06开尔文和 +0.05开尔文。CPLD中的冷却作用比FIXDST更强，这是由于在沙尘 - 气候相互作用下CPLD中的沙尘负荷比FIXDST高13%。尽管从全球和年平均的角度来看，沙尘的长波辐射效应预计会抵消其短波效应的很大一部分，但沙尘的短波效应在白天占主导，长波效应在夜间占主导，这对温度预测非常重要。例如，在撒哈拉沙漠上空，在FIXDST模拟中，年平均、年平均白天和年平均夜间地表气温的变化预计分别为 +0.32开尔文、 -0.11开尔文和 +0.68开尔文。在CPLD模拟中，沙尘的长波和短波辐射效应预计对沙尘循环有不同的影响；太阳辐射效应通过增加地表湿度和降低地表风速减少沙尘排放，而热效应则通过气象参数的相反变化增加沙尘扬起。
[1] We examine equilibrium climate responses to the shortwave and/or longwave direct radiative effect of mineral dust aerosol using the Global transport Model of Dust (GMOD) embedded within a general circulation model (GCM). The presence of mineral dust aerosol in the atmosphere is estimated to exert global mean shortwave and longwave radiative forcings (RF) of -0.25 W m ―2 and +0.27 W m ―2 , respectively, at the top of the atmosphere (TOA) and —1.95 W m ―2 and +0.61 W m ―2 at the surface. Climatic effect of dust is simulated using two different approaches. In the first approach, monthly mean fields of dust simulated a priori are used in the radiative transfer module of the GCM to drive climate change, with levels of dust fixed during the climate integration (denoted as simulation FIXDST). In the second approach, dust aerosol interacts online with meteorology through the dust cycle and its direct radiative effect (denoted as simulation CPLD). With both longwave and shortwave RF of dust, predicted changes in global and annual mean surface air temperature and air temperature at 200 hPa are zero and +0.12 K, respectively, in FIXDST, and -0.06 K and +0.05 K in the CPLD simulation. The stronger cooling in CPLD than in FIXDST is a result of a 13% higher dust burden in CPLD with dust-climate interactions. Although dust longwave radiative effect is predicted to offset a large portion of its shortwave effect on a global and annual mean basis, dust shortwave effect dominates during the daytime, and the longwave effect prevails at night, which is found to be very important for predictions of temperature. For example, over the Sahara Desert, the changes in annual mean, annual mean daytime, and annual mean nighttime surface air temperature are predicted to be +0.32 K, -0.11 K, and +0.68 K, respectively, in the FIXDST simulation. The longwave and shortwave radiative effects of dust are predicted to have different impacts on the dust cycle in CPLD simulation; the solar radiative effect reduces dust emissions by increasing surface humidity and by reducing surface wind speed, while the thermal effect increases dust uplift through opposite changes in the meteorological parameters.