新论文介绍:Direct Climatic Effect of Dust Aerosol in the NCAR Community Atmosphere Model Version 3 (CAM3)

[发布日期: 2014-12-30 浏览量 638]

Direct climate responses to dust shortwave and longwave radiative forcing (RF) are studied using the NCAR Community Atmosphere Model Version 3 (CAM3). The simulated RF at the top of the atmosphere (TOA) is ¡0.45 W m¡2 in the solar spectrum and +0.09 W m¡2 in the thermal spectrum on a global average. The magnitude of surface RF is larger than the TOA forcing, with global mean shortwave forcing of ¡1.76 W m¡2 and longwave forcing of +0.31 W m¡2. As a result, dust aerosol causes the absorption of 1.1 W m¡2 in the atmosphere. The RF of dust aerosol is predicted to lead to a surface cooling of 0.5 K over the Sahara Desert and Arabian Peninsula. In the meantime, the upper troposphere is predicted to become warmer because of the absorption by dust. These changes in temperature lead to a more stable atmosphere, which results in increases in surface humidity. The upward sensible and latent heat °uxes at the surface are reduced, largely balancing the surface energy loss caused by the backscattering and absorption of dust aerosol. Precipitation is predicted to decrease moderately on a global scale.