Analysis of cirrus in the tropical tropopause layer from CALIPSO and MLS data: A water perspective
Analysis of cirrus in the tropical tropopause layer from CALIPSO and MLS data: A water perspective
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DOI：
10.1029/2011jd016442
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发表时间：
2012-02
影响因子：
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通讯作者：
Tao Wang;A. Dessler
中科院分区：
文献类型：
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作者：
Tao Wang;A. Dessler
[1]热带对流层顶卷云的形成主要有两种机制：深对流砧的疏散和原位形成。通过分析水汽（H2O）测量的光环微波临边探测器（MLS）和冰水含量（IWC）测量的云气溶胶激光雷达和红外线探路者卫星观测（CALIPSO），我们确定TTL卷云，包含太多的冰已经形成原位，因此必须对流起源。分析3年（2008 - 2010年）的CALIPSO测量，我们发现对流卷云的发生三个最大值：赤道非洲，热带西太平洋和南美洲。在整个热带地区，我们发现，对流卷云更频繁地发生在北方冬春季和较少发生在北方夏秋季。卷云的对流分数也增加，直到冷点对流层顶在大多数季节达到这意味着对流层顶周围的卷云是对流起源的概率较高。经过3年的平均，我们发现TTL中至少有30%的卷云是由对流引起的。
[1] Two mechanisms are thought to be primarily responsible for the formation of cirrus in the Tropical Tropopause Layer (TTL): detrainment from deep convective anvils and in situ initiation. By analyzing water vapor (H2O) measurements from the Aura Microwave Limb Sounder (MLS) and ice water content (IWC) measurements from the Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observations (CALIPSO), we identify TTL cirrus that contain too much ice to have been formed in situ—and therefore must be of convective origin. Analyzing 3 years of CALIPSO measurements (2008–2010), we found three maxima in the occurrence of convective cirrus: equatorial Africa, the tropical western Pacific, and South America. Over the entire tropics, we found that convective cirrus occur more frequently during boreal winter-spring and less frequently during boreal summer-fall. The convective fractions of cirrus also increase until the cold point tropopause is reached in most seasons—implying higher probabilities of cirrus around the tropopause being of convective origin. Averaged over 3 years, we find that at least ∼30% of cirrus in the TTL are definitely of convective origin.