Formation and Evolution of Pileus Cloud Near the Tropopause

在14 - 18公里高度的对流层顶过渡层（TTL）中，薄卷云层广泛分布。它们在气候、平流层湿度和遥感方面的作用最近引起了相当大的关注。然而，由于云层非常稀薄和非常高，它们的起源在很大程度上仍然不确定。这项研究探讨了一个假设，即一些TTL卷云起源于菌盖云-薄的层状冷凝层，形成之前的强对流隆起-随后演变为覆盖大面积的热带地区。看来，至少在其初始阶段，菌盖演变的问题，基本上是确定大气深对流力的分层TTL运动之一。利用一个大涡模拟云分辨模式研究了对流与环境相互作用形成菌盖云的三种主要情景，并从对流层顶过渡层卷云在气候和平流层湿度控制中的重要作用引出了这项研究的更广泛的影响。此外，该补助金还资助了一名女研究生。

Thin layers of cirrus are widespread in the tropopause transition layer (TTL) between 14 and 18 km altitude. They have attracted considerable recent attention for their role in climate, stratospheric humidity, and remote sensing. However, because the clouds are very tenuous and very high, their origins remain largely uncertain. This study explores a hypothesis that some TTL cirrus originates as pileus cloud - thin stratiform layers of condensate that form ahead of vigorous convective uplift - that subsequently evolve to cover large areas of the tropics. It appears that, at least in its initial stages, the problem of pileus evolution is essentially one of determining how atmospheric deep convection forces motions in the stratified TTL. A large-eddy-simulation cloud resolving model is used to investigate three main scenarios of the how convection interacts with its environment to form pileus clouds.The broader impacts of this study are derived from the important roles that tropopause transition layer cirrus have in climate and in controlling stratospheric humidity. Moreover, this grant supports one female graduate student.