本文利用卫星CloudSat同时结合了与其同轨道的卫星CALIPSO(Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observations)2007至2009年3年的观测资料,将东亚地区划分为六个研究区域,着重研究了东亚地区云垂直分布的统计特征.结果表明：东亚地区不同高度的云量之和具有明显的季节变化趋势,夏季最大,春秋次之,冬季最小.海洋上空的单层云量最大值出现在冬季,而在陆地上空则出现在夏季.从云出现概率来看,东亚地区单层云出现的概率在春、夏、秋、冬季节依次为52.2%,48.1%,49.2%和51.9%,而多层(2层和2层以上)云出现的概率在春、夏、秋、冬季节分别为24.2%,31.0%,19.7%,15.8%.云出现的总概率和多层云出现的概率,在六个区域都呈现出夏季最大,冬季最小;对4个季节都呈现出东亚南部比东亚北部大,海洋上空比陆地上空大的特点,表明云出现的总概率的季节变化主要由多层云出现的概率的变化决定.东亚地区云系统中最高层云云顶的高度,在夏季最高,为15.9 km,在冬季最低,为8.2 km;在东亚南部和海洋上空较高,平均为15.1 km;在东亚北部较低,平均为12.1 km,且呈现东亚南北部之间差异较大的特点.东亚地区云系统的云层厚度基本位于1 km到3 km之间,且夏季大,冬季小;对同一季节,不同区域的云层厚度差别较小;当多层云系统中的云层数目增加时,云层的平均厚度减少,且较高层的云层平均厚度大于较低层的.云层间距的概率分布基本呈单峰分布,出现峰值范围的云层间距在1到3 km之间,各区域之间没有明显差别,季节变化也不大.本文的研究为在气候模式中精确描述云的垂直结构提供了有用的参数化依据.
Statistical characteristics of the vertical structure of clouds over East Asia are obtained by dividing the area into six regions and analyzing the 2007, 2008, and 2009 datasets from the cloud observing satellite CloudSat and Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observations (CALIPSO). Results indicate that the total cloud amount exhibits a distinct tendency of seasonal change at various altitudes, reaching a maximum in summer and minimum in winter. The maximum value of single-layer cloud amount appears in winter above the ocean and in summer above land. The frequency of occurrence of single-layer clouds in East Asia is 52.2%, 48.1%, 49.2%, and 51.9% for spring, summer, autumn, and winter, respectively; that for multilayer clouds is 24.2%, 31.0%, 19.7%, and 15.8%, respectively. For all six regions, the frequency of occurrence for both types of clouds is highest in summer and lowest in winter. In all four seasons, cloud frequency in the southern region of East Asia is higher than that in the northern region and is greater above the ocean than that above land. These results indicate that variance in the frequency of occurrence for total clouds is decided by that of multilayer clouds. Cloud top height of the highest cloud layer in East Asia reaches a maximum in summer and minimum in winter at 15.1 km and 8.2 km, respectively. The difference in levels is higher in the southern region above the ocean than in the northern region above land at 15.1 km and 12.1 km, respectively. In addition, the thickness of the cloud layer ranges from 1 km-3 km and is largest in summer and smallest in winter; little difference appears among the regions. Moreover, when the number of cloud layers in the multilayer cloud system increases, the mean cloud thickness decreases, and the mean thickness of the higher cloud layer is larger than that of the lower. The intervals among cloud layers show single peak distribution with the peak value appearing between 1 km and 3 km; differences among regions and seasons are minimal. This work supplies useful information for accurate parameterization of vertical cloud structures.
彭杰,张华,沈新勇.东亚地区云垂直结构的CloudSat卫星观测研究.大气科学,2013,37(1):91~100 PENG Jie, ZHANG Hua, SHEN Xinyong. Analysis of Vertical Structure of Clouds in East Asia with CloudSat Data. Chinese Journal of Atmospheric Sciences (in Chinese),2013,37(1):91~100复制