An optical model accounting for the East Asian dust is proposed as a result of theory calculation and compo-sition analysis of the aerosol samples collected in China de-sert during the international project, Studies o...An optical model accounting for the East Asian dust is proposed as a result of theory calculation and compo-sition analysis of the aerosol samples collected in China de-sert during the international project, Studies on the Origin and Transport of Aeolian Dust and its Effects on Climate (ADEC). Study indicates that dust aerosols emitting from China deserts have smaller imaginary parts of refractive indices, therefore absorb less and scatter more solar radia-tion than the most dust optical models published so far. Fur-thermore, the forward fraction of scattering is less and the backscattering is stronger than those of the other models. The seasonal averaged radiative forcing in spring, 2001 over east Asia-north Pacific region is simulated employing the new dust optical model. The net forcing at the top of atmos-phere (TOA) is estimated as -0.943 W·m-2 for regional and seasonal mean, with shortwave and longwave contributions of -1.700 and 0.759 W·m-2, respectively. The surface net forcing is calculated to be -5.445 W·m-2, and made up of shortwave component of -6.250 W·m-2 and longwave component of +0.759 W·m-2. The distributions of TOA and surface net forcing over this region are also analyzed in this study.展开更多
The International Satellite Cloud Climatology Project (ISCCP) D2 dataset is used to study the global dis- tribution of low, middle and high cloud amounts and their trends of 1983—2001. Evidences have shown that globa...The International Satellite Cloud Climatology Project (ISCCP) D2 dataset is used to study the global dis- tribution of low, middle and high cloud amounts and their trends of 1983—2001. Evidences have shown that global warming has accelerated over the past 20 a and the 1990s was the warmest decade in the instrumental records since 1861. Trends of various clouds amounts over this period are analyzed by employing the linear regression method. The results show that global mean total cloud amounts, in general, have tended to reduce over the past 20 a. But there are slightly increasing by about 2% before 1987 and decreasing by about 4% since then. Cloudiness trends of both low and high clouds decrease while increase for the middle cloud. And there exist remarkable discrepancies in different regions. The preliminary analyses suggest that it is likely that the cloud change occurring over the past 20 a is a positive feed- back to global warming.展开更多
文摘An optical model accounting for the East Asian dust is proposed as a result of theory calculation and compo-sition analysis of the aerosol samples collected in China de-sert during the international project, Studies on the Origin and Transport of Aeolian Dust and its Effects on Climate (ADEC). Study indicates that dust aerosols emitting from China deserts have smaller imaginary parts of refractive indices, therefore absorb less and scatter more solar radia-tion than the most dust optical models published so far. Fur-thermore, the forward fraction of scattering is less and the backscattering is stronger than those of the other models. The seasonal averaged radiative forcing in spring, 2001 over east Asia-north Pacific region is simulated employing the new dust optical model. The net forcing at the top of atmos-phere (TOA) is estimated as -0.943 W·m-2 for regional and seasonal mean, with shortwave and longwave contributions of -1.700 and 0.759 W·m-2, respectively. The surface net forcing is calculated to be -5.445 W·m-2, and made up of shortwave component of -6.250 W·m-2 and longwave component of +0.759 W·m-2. The distributions of TOA and surface net forcing over this region are also analyzed in this study.
文摘The International Satellite Cloud Climatology Project (ISCCP) D2 dataset is used to study the global dis- tribution of low, middle and high cloud amounts and their trends of 1983—2001. Evidences have shown that global warming has accelerated over the past 20 a and the 1990s was the warmest decade in the instrumental records since 1861. Trends of various clouds amounts over this period are analyzed by employing the linear regression method. The results show that global mean total cloud amounts, in general, have tended to reduce over the past 20 a. But there are slightly increasing by about 2% before 1987 and decreasing by about 4% since then. Cloudiness trends of both low and high clouds decrease while increase for the middle cloud. And there exist remarkable discrepancies in different regions. The preliminary analyses suggest that it is likely that the cloud change occurring over the past 20 a is a positive feed- back to global warming.
