Radiative Forcing and Climate Response due to Black Carbon in Snow and Ice
【摘要】：The radiative forcing and climate response due to black carbon (BC) in snow/ice are investigated by integrating observed effects of BC on snow/ice albedo into an atmospheric general circulation model (BCC_AGCM2.0.1) developed by the National Climate Center (NCC) of the China Meteorological Administration (CMA). The results show that the global annual mean surface radiative forcing due to BC in snow/ice is +0.042 W m -2 , with maximum forcing found over the Tibetan Plateau and regional mean forcing exceeding +2.8 W m -2 . The global annual mean surface temperature is increased 0.071 o C by BC in snow/ice. Positive surface radiative forcing is clearly shown in winter and spring and increases the surface temperature of snow/ice in the Northern Hemisphere. The surface temperatures of snow-covered areas of Eurasia and North America in winter (spring) are increased by 0.83(0.6) o C and 0.83(0.46) o C, respectively. Snow-melt rates are also increased greatly, leading to earlier snowmelt and peak runoff timings. With the rise of surface temperature in the Arctic, more water vapor could be released into the atmosphere, allowing for easier cloud formation, which could lead to higher thermal emittance in the Arctic. However, the total cloud forcing could be decreased due to the increasing of cloud cover, which will offset some of the cloud positive feedback mechanism.