Characteristics of cloud overlap over Eastern Asia are analyzed using a threeyear dataset （20072009） from the cloud observing satellite CloudSat. Decorrelation depth Lis retrieved, which represents cloud overlap cha...Characteristics of cloud overlap over Eastern Asia are analyzed using a threeyear dataset （20072009） from the cloud observing satellite CloudSat. Decorrelation depth Lis retrieved, which represents cloud overlap characteristics in the simulation of cloudradiation processes in global climate models. Results show that values of L in six study regions are generally within the range 03 km. By categorizing L according to cloud amount in subregions, peak L appears near subregions with cloud amount between 0.6 and 0.8. Average L is 2.5 km. L at higher altitudes is generally larger than at lower lati tudes. Seasonal variations of L are also clearly demonstrated. The sensitivity of cloud radiative forcing （CRF） to L;y in Community Atmosphere Model 3.0 of the National Center for Atmospheric Research （CAM3/NCAR） is analyzed. The result shows that L can have a big impact on simulation of CRF, especially in major monsoon regions and the MidEastern Pacif ic, where the difference in CRF can reach 4050 W m2. Therefore, accurate parameterization of cloud vertical overlap struc ture is important to CRF simulation and its feedback to climate.展开更多
基金supported by National Basic Research Program of China (Grant No. 2011CB403405)National Natural Science Foundation of China (Grant No. 41075056)Public Meteorology Special Foundation of MOST (Grant No. GYHY201106022)
文摘Characteristics of cloud overlap over Eastern Asia are analyzed using a threeyear dataset （20072009） from the cloud observing satellite CloudSat. Decorrelation depth Lis retrieved, which represents cloud overlap characteristics in the simulation of cloudradiation processes in global climate models. Results show that values of L in six study regions are generally within the range 03 km. By categorizing L according to cloud amount in subregions, peak L appears near subregions with cloud amount between 0.6 and 0.8. Average L is 2.5 km. L at higher altitudes is generally larger than at lower lati tudes. Seasonal variations of L are also clearly demonstrated. The sensitivity of cloud radiative forcing （CRF） to L;y in Community Atmosphere Model 3.0 of the National Center for Atmospheric Research （CAM3/NCAR） is analyzed. The result shows that L can have a big impact on simulation of CRF, especially in major monsoon regions and the MidEastern Pacif ic, where the difference in CRF can reach 4050 W m2. Therefore, accurate parameterization of cloud vertical overlap struc ture is important to CRF simulation and its feedback to climate.
