Cirrus clouds at heights of 10–18 km are investigated for the seasonal migrations based on 3 years observations of CALIOP (Cloud-Aerosol Lidar with Orthogonal Polarization) in 2008–2012. Past studies have shown cirrus clouds migrate from their winter peaks in the equatorial regions to the maximum latitudes of ± 30° in the boreal summer as the migration of ITCZ (Intertropical Convergence Zone). However, this general picture does not show detailed distributions by including height, seasons and latitudinal dependences considering cirrus extended height and latitudinal coverages. We are also interested in understanding the occurrences of thin cirrus in the tropical tropopause and formation of all cirrus in the extratropics where little studies about their migration have been made. It is not well know if the summer enhancement in the extratropics is only related to the migration or by other factors. Cirrus distributions are studied in two height groups of low (< 15 km) or high cirrus (> 15 km), and in three regions of EQ (− 15° to 15° latitudes), NH (15°–30°), and SH (− 15° to − 30°) for different seasons. Our results show a major part of cirrus, the low cirrus, migrate to the extratropics in the summer. Like ITCZ, they stay mostly in the north (64%) less in the south (36%) following the same migration pattern. High cirrus cloud is decoupled from ITCZ with the major part showing a boreal winter peak spread to higher latitudes with seasons. In the extratropics, enhanced production of high cirrus can be attributed to the convective production in the summer monsoons. The summer convective production is used to estimate the formation of equatorial high cirrus in terms of rapid convection or slow ascending with a ratio determined.

中文翻译：

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使用 CALIOP 观测的卷云季节性迁移

基于 2008-2012 年对 CALIOP（具有正交极化的云气溶胶激光雷达）的 3 年观测，调查了 10-18 公里高度的卷云的季节性迁移。过去的研究表明，卷云随着 ITCZ（热带辐合带）的迁移从赤道地区的冬季高峰迁移到北半球夏季的最大纬度 ± 30°。然而，考虑到卷云的延伸高度和纬度覆盖率，这张总图并没有通过包括高度、季节和纬度依赖性来显示详细的分布。我们也有兴趣了解热带对流层顶薄卷云的出现和温带地区所有卷云的形成，但很少有关于它们迁移的研究。目前尚不清楚温带地区夏季的增强是仅与迁移有关还是与其他因素有关。卷云分布在低（< 15 公里）或高（> 15 公里）两个高度组以及 EQ（纬度 - 15° 至 15°）、NH（15°–30°）和三个区域进行研究不同季节的 SH（- 15° 至 - 30°）。我们的结果表明，卷云的主要部分，低卷云，在夏季迁移到温带地区。与 ITCZ 一样，他们遵循相同的迁移模式，主要留在北部 (64%)，而南部 (36%) 较少。高卷云与 ITCZ 分离，主要部分显示北方冬季峰值随季节扩展到高纬度地区。在温带地区，高卷云产量的增加可归因于夏季季风中的对流产生。