The Distribution of Cloud Horizontal Sizes
The Distribution of Cloud Horizontal Sizes
复制标题
云水平尺寸的分布
DOI：
10.1175/2011jcli4056.1
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发表时间：
2011
影响因子：
4.9
通讯作者：
P. Field
中科院分区：
文献类型：
--
作者：
R. Wood;P. Field
本文给出了近全球卫星资料、飞机资料和全球高分辨率数值天气预报模式的云水平尺度分布，其尺度范围为0.1-8000 km，在0.1 - 1500 km或更大范围内，用指数β = 1.66 ±0.04的单一幂律关系很好地表示。在大于1500公里的尺度上，有一个统计上显著的尺度突变，比幂律预期的更少的非常大的云。对尺寸分布进行积分，以确定大于给定尺寸的云对云量和可见光反射率的贡献。在全球范围内，云与200公里或更大的水平尺寸构成约50%的云量和60%的反射率，这一结果是不敏感的最小尺寸阈值假设在积分假设幂律可以外推到100米以下的规模。结果对是否用云谱法测定粒度分布也不敏感。
AbstractCloud horizontal size distributions from near-global satellite data, from aircraft, and from a global high-resolution numerical weather prediction model, are presented for the scale range 0.1–8000 km and are shown to be well-represented using a single power-law relationship with an exponent of β = 1.66 ±0.04 from 0.1 to 1500 km or more. At scales longer than 1500 km, there is a statistically significant scale break with fewer very large clouds than expected from the power law. The size distribution is integrated to determine the contribution to cloud cover and visible reflectance from clouds larger than a given size. Globally, clouds with a horizontal dimension of 200 km or more constitute approximately 50% of the cloud cover and 60% of the reflectance, and this result is not sensitive to the minimum size threshold assumed in the integral assuming that the power law can be extrapolated below 100-m scale. The result is also not sensitive to whether the size distribution is determined using cloud se...