Unexpected peak near −15°C in CloudSat echo top climatology
Unexpected peak near −15°C in CloudSat echo top climatology
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DOI：
10.1029/2009gl037558
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发表时间：
2009-05
影响因子：
5.2
通讯作者：
E. Riley;B. Mapes
中科院分区：
文献类型：
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作者：
E. Riley;B. Mapes
我们研究了地球云量的雷达衍生气候学，重点关注回波顶的垂直分布。在与低云和高云分别有关的~ 2 km和~ 14 km两个主峰之间，有两个明显的热带中层峰。一个在5-6公里层，另一个在7 - 8公里层。无论是白天还是黑夜，无论是陆地还是海洋，无论是热带海盆，还是已出版的地面雷达气候学，都能看到它们。在温带地区，温度垂直回波顶分布在−15 ~−20℃层有一个明显的峰值（对应于热带地区的7 ~ 8 km峰值）。再一次，信号是强大的（夜间-白天，陆地-海洋，夏季-冬季）。我们考虑了对- 15°C峰值的解释，从数据伪像（不太可能）到单纯的雷达增亮，再到可能真正的微物理或动态云增强机制。
We examine a radar‐derived climatology of Earth's cloudiness, focusing on the vertical distribution echo tops. Between the two main peaks at ∼2 km and ∼14 km associated with low and high clouds, respectively, lie two distinct midlevel peaks in the tropics. One is in the 5–6 km layer, the other between 7 and 8 km. Both are seen day and night, over land and sea, over each tropical ocean basin, and in published ground radar climatology. In the extratropics, the vertical echo top distribution by temperature reveals a strikingly sharp peak in the −15 to −20°C layer (corresponding to the 7–8 km peak in the tropics). Again the signal is robust (night‐day, land‐sea, summer‐winter). We consider interpretations of the −15°C peak ranging from data artifacts (unlikely), to mere radar brightening, to possible true microphysical or dynamical cloudiness enhancement mechanisms.