Fine-Scale Turbulence, Cloud Microphysics, and Radiative Cooling Rate Measurements in the Entrainment Interface Layer of Marine Stratocumulus

海洋层积云夹带界面层的细尺度湍流、云微物理和辐射冷却速率测量

• 批准号: 275522730
• 负责人: Dr. Holger Siebert
• 金额: --
• 依托单位: Leibniz-Institut für Troposphärenforschung e.V. (TROPOS)
• 依托单位国家: 德国
• 项目类别: Research Grants
• 财政年份: 2015
• 资助国家: 德国
• 起止时间: 2014-12-31 至 2018-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/275522730?language=en
• 关键词: Fine; Scale; Turbulence; Cloud; Microphysics

Although much progress has been achieved in the general understanding ofmixing and radiative processes of Stratocumulus (Sc), the representation of feedback processes of Sc clouds causes significant uncertains in climate projections. These uncertainties are partly caused by problems in understanding and realistically describing fine-scale mixing mainly at cloud top. Cloud top cooling (entrainment, radiative and evaporative cooling) and dynamic/turbulent processes are strongly linked. Cloud top cooling results in a buoyancy reduction which induces vertical motion within the clouds. Vertical motion subsequently generates turbulence that increases entrainment processes and associated evaporative cooling. In order to investigate these processes we suggest the following project objectives: (a) to improve the understanding of the fine-scale structure of the entrainment interface layer (EIL), (b) to quantify the influence of the EIL on the entrainment in Sc clouds, and (c) to evaluate the role of radiative heating and cooling rates in cloud entrainment and convection processes. In order to reach these goals observations with a modified version of the established, helicopter--borne, combined sensor package ACTOS (Airborne Cloud Turbulence Observation System) and SMART--HELIOS (Spectral Modular Airborne Radiation measurement sysTem) will be performed in an observational campaign at the Azores. Both instrumental platforms are carried as external cargo by a helicopter with low true airspeed.The unique sensor package enables in-situ measurements of dynamic, thermodynamic, cloud microphysical, and radiative parameters with a high spatial resolution (mostly in the decimeter range). No other measurement platform world-wide can achieve such a high resolution which is, however, crucial to achieve the general aims of this proposal. This is particular true considering that the EIL can have thickness as small as 10 m, therefore, high measurement resolution is critical.

尽管在层流（SC）的混合和辐射过程的一般理解中取得了很多进展，但SC云的反馈过程的表示会导致气候预测的重大不确定性。这些不确定性部分是由于理解和现实描述主要在云顶部进行的精细尺度混合而引起的。云顶冷却（夹带，辐射和蒸发冷却）和动态/湍流过程密切相关。云顶冷却导致浮力减少，从而在云中诱导垂直运动。垂直运动随后产生湍流，从而增加了夹带过程并相关的蒸发冷却。为了研究这些过程，我们建议以下项目目标：（a）提高对夹带界面层（EIL）的精细尺度结构（b）的理解，以量化EIL对SC云中夹带的影响，以及（c）评估云隔开和对交流过程中辐射性加热和冷却速率的作用。为了通过修改的已建立的直升机 - 播种，合并的传感器包（空中云湍流观测系统）和Smart-Helios（Spectral模块化机载辐射测量系统）的修改版本来达到这些目标观察。这两个仪器平台均由较低的真实空速的直升机作为外部货物携带。独特的传感器包装可实现对动态，热力学，云微物理和辐射参数的原位测量，其空间分辨率很高（大多数在折射率范围内）。全球范围内没有其他测量平台可以实现如此高的分辨率，但是对于实现该提案的总体目标至关重要。考虑到EIL的厚度可以较小至10 m，因此这是事实，因此，高测量分辨率至关重要。

项目成果

Observations of Aerosol, Cloud, Turbulence, and Radiation Properties at the Top of the Marine Boundary Layer over the Eastern North Atlantic Ocean: The ACORES Campaign

• DOI: 10.1175/bams-d-19-0191.1
• 发表时间: 2020-08
• 期刊: Bulletin of the American Meteorological Society
• 影响因子: 8
• 作者: H. Siebert;K. Szodry;U. Egerer;B. Wehner;S. Henning;Karine Chevalier;J. Lückerath;O. Welz;K. Weinhold;Felix Lauermann;M. Gottschalk;A. Ehrlich;M. Wendisch;P. Fialho;G. Roberts;Nithin Allwayin;S. Schum;R. Shaw;C. Mazzoleni;L. Mazzoleni;J. Nowak;S. Malinowski;K. Karpińska;Wojciech Kumala;D. Czyzewska;E. Luke;P. Kollias;R. Wood;J. Mellado