摘要:基于2003~2016年MODIS/Aqua（MODerate resolution Imaging Spectroradiometer）云产品资料（MYD08_D3），分析了中国东部大陆及其邻近海域云量（CF）、云滴有效半径（CER）、和液水路径（LWP）的空间分布以及季节变化，并结合同期ERA-Interim再分析资料的850 hPa垂直速度（ω850hPa）、低对流层稳定度（LTS）、以及MODIS/Aqua水汽产品中的大气可降水量（PWV）资料，分析了云宏微观物理量与动力、热力及水汽条件之间的关系。从空间分布来看，夏季由日本海至中南半岛存在一个东北西南走向的云量高值区，覆盖我国东部地区，冬季云量高值区位于我国南方地区和东部海域上空；云滴有效半径冬、夏分布类似，均为由东南洋面至西北内陆递减；夏季液水路径分布较为均一，冬季空间差异很大，30°N是明显的高低值分界线，这与冬季水汽的分布密切相关。陆地和海洋上云量均呈冬高夏低的变化趋势，陆地大于海洋，而云滴有效半径和液水路径则为夏高冬低，海洋大于陆地。总体来说，云量与PWV和LTS均表现为正相关、与ω850hPa呈负相关，表明低层的上升运动有利于水汽向上输送、凝结形成云，但稳定的大气层结又会阻碍云进一步向上发展，使其被限制在底层空间，由于本文的研究对象为暖云，多为中低云，因而云量较高；云滴有效半径和液水路径均与LTS、ω850hPa表现为负相关，但是对PWV的变化不是很敏感，表明水汽并不是影响云滴尺度和液水路径的主导因素，其主要受动力、热力抬升作用的影响；以上关系在不同区域、不同季节的表现存在一定差异。
关键词:MODIS (MODerate resolution Imaging Spectroradiometer)/
云量/
云滴有效半径/
液水路径/
气象条件
Abstract:Spatial distribution and seasonal variation of cloud properties in eastern China and its adjacent ocean are analyzed based on MODerate resolution Imaging Spectroradiometer (MODIS) level three daily cloud products from 2003 to 2016. The relationships of cloud properties with dynamic and thermodynamic conditions and water vapor condition are investigated by combining MODIS and ERA-Interim reanalysis data over the same period. The high cloud fraction (CF) area is found over eastern China in the summer and over southern China and eastern ocean in the winter. The cloud droplet effective radius (CER) decreases from eastern ocean to inland region in both the summer and winter. Compared to that in the summer, the spatial distribution pattern of liquid water path (LWP) in the winter is greatly inhomogeneous with a dividing line between high and low values located near 30°N, which corresponds to the distribution of water vapor. It is found that CF exhibits the same seasonal variation over the land and ocean, i.e., low in summer and high in winter, but the magnitude is larger in eastern China land area than in the adjacent ocean. On the contrary, the CER and LWP are greater over the land than over its adjacent ocean with lower values in the winter and higher values in the summer. In general, CF has an obvious positive correlation with precipitable water vapor (PWV) and low troposphere stability (LTS) and a negative correlation with 850-hPa vertical velocity (ω850hPa), which indicates that abundant moisture and ascending motion in lower levels are favorable for the formation of clouds while the stable atmospheric stratification suppresses the growth of clouds. This explains why cloud fraction in the middle and lower levels is high. Both the CER and LWP show negative correlations with LTS and ω850hPa. However, they display low sensitivity to variations of PWV, which suggests that the CER and LWP are mainly affected by dynamic and thermodynamic lifting instead of the atmospheric moisture condition.
Key words:MODIS (MODerate resolution Imaging Spectroradiometer)/
Cloud fraction/
Cloud droplet effective radius/
Liquid water path/
Meteorological conditions
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http://www.iapjournals.ac.cn/qhhj/article/exportPdf?id=20180609
