Understanding clouds and precipitation at the sub kilometer scale using HAMP – The edge of shallow precipitation (UCP-HAMP-Edge)

降水的形成是信风区通过限制边界层和对流云的增长来维持分散的浅积云状态的关键过程。这种效应在一定程度上决定了浅云对全球变暖的反应，以及这些云是否会加速或减缓气候变化。控制浅云是否开始降水的影响因素尚未完全揭示，特别是由于缺乏全面的观测。利用研究飞机HALO进行的EUREC4A（阐明云环流耦合在气候中的作用）测量活动将克服这一限制，同时提供云宏观和微观物理特性的观测以及亚公里尺度上的凝结水负荷，以及大尺度动力学和潜在能量和水分通量的估计。EUREC4A将于2020年1月和2月进行，探索巴巴多斯的云层。提议者是发起这项运动的国际团队的一部分，并将操作“HALO微波包”（HAMP），该包由HALO上的微波辐射计和云雷达组成。作为解决科学问题的基础，我们将开发协同云和雨检索，并扩展分段云数据库，包括之前的NARVAL活动。该数据集既用于卫星评估，也用于评估网格间距在100米至几公里之间的下一代大气模式。

The formation of precipitation is a key process in the trade wind region to maintain a scattered shallow cumulus regime by limiting the growth of the boundary layer and of convective clouds. This effect partly determines how shallow clouds will respond to global warming and whether these clouds accelerate und reduce the climate change. The influencing factors controlling whether a shallow cloud starts to precipitate are yet not fully unraveled, in particular due to a lack of comprehensive observations. The measurement campaign EUREC4A (Elucidating the Role of Cloud-Circulation Coupling in Climate) using the research aircraft HALO will overcome this limitation and provide simultaneously observations of cloud macro- and microphysical properties and the condensate load at the sub kilometer scale as well as estimates of the large scale dynamics and underlying energy and moisture fluxes. EUREC4A will take place at January and February 2020 and explore clouds eats of Barbados. The proposers are part of the international team, which initiated this campaign, and will operate the "HALO microwave package" (HAMP) consisting of microwave radiometers and a cloud radar onboard of HALO. As basis to address the science question we will develop of synergistic cloud and rain retrievals and the extension of a segmented cloud database including also the preceding NARVAL campaigns. This data set is used both for satellite evaluation and to evaluate the next generation of atmospheric models with grid spacing between 100m and a few kilometers.