Mean and turbulence structure of the summertime Arctic cloudy boundary layer
Mean and turbulence structure of the summertime Arctic cloudy boundary layer
复制标题
夏季北极多云边界层的平均和湍流结构
DOI：
10.1002/qj.49711448109
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发表时间：
1988
影响因子：
8.9
通讯作者：
G. Herman
中科院分区：
文献类型：
--
作者：
J. Curry;E. Ebert;G. Herman
使用 1975 年和 1980 年在波弗特海上空进行的一系列飞机观测数据描述了存在层云的夏季北极行星边界层的结构。研究的多云边界层可分为三组：（1）稳定的边界层，具有薄的、斑片状的云，可能出现在许多层中； (2) 稳定的边界层，通常含有雾，其上方是云顶混合层； (3)从地表延伸的云顶混合层。根据飞机观测，讨论了已应用于北极的几种现有的多云边界层模型。
选择风速信号相对较高的两种情况来详细分析平均和湍流特征。观测到的等效位温平均收支一般由辐射项和平流项主导，而水分收支则由平流项和湍流项主导。还研究了夏季北极多云边界层中产生和破坏湍流动能的过程。北极多云边界层中湍流动能产生的主要模式是由于云非绝热过程而在云内产生的浮力。本文特别关注与云相关的非绝热过程（辐射和凝结加热）在改变边界层湍流结构中的作用。将这两种情况与先前文献中描述的海洋层积云进行了比较。
The structure of the summertime Arctic planetary boundary layer in the presence of a stratus cloud cover is described using the data from a series of aircraft observations made during 1975 and 1980 over the Beaufort Sea. The cloudy boundary layers that were studied can be classified into three groups: (1) a stable boundary layer with thin, patchy clouds that may occur in numerous layers; (2) a stable boundary layer, frequently containing a fog, that is surmounted by a cloud-topped mixed layer; and (3) a cloud-topped mixed layer that extends from the surface. Several existing models of the cloudy boundary layer that have been applied to the Arctic are discussed in light of the aircraft observations.
Two cases with relatively high wind velocity signals have been chosen for detailed analysis of the mean and turbulence characteristics. The observed mean budgets of equivalent potential temperature were generally dominated by the radiative and advective terms, while the moisture budgets were dominated by advection and the turbulent fluxes. The processes that act to produce and destroy turbulence kinetic energy in the summertime Arctic cloudy boundary layer are also examined. The dominant mode of turbulence kinetic energy production in the Arctic cloudy boundary layer is the buoyancy produced within the cloud due to the cloud diabatic processes. This paper focuses particularly on the role of diabatic processes (radiative and condensational heating) associated with the cloud in modifying the turbulence structure of the boundary layer. A comparison is made of these two cases with the marine stratocumulus layers previously described in the literature.