Global S&T Development Trend Analysis Platform of Resources and Environment
DOI | 10.5194/acp-17-13317-2017 |
The role of 1-D and 3-D radiative heating in the organization of shallow cumulus convection and the formation of cloud streets | |
Jakub, Fabian; Mayer, Bernhard | |
2017-11-09 | |
发表期刊 | ATMOSPHERIC CHEMISTRY AND PHYSICS
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ISSN | 1680-7316 |
EISSN | 1680-7324 |
出版年 | 2017 |
卷号 | 17期号:21 |
文章类型 | Article |
语种 | 英语 |
国家 | Germany |
英文摘要 | The formation of shallow cumulus cloud streets was historically attributed primarily to dynamics. Here, we focus on the interaction between radiatively induced surface heterogeneities and the resulting patterns in the flow. Our results suggest that solar radiative heating has the potential to organize clouds perpendicular to the sun's incidence angle. To quantify the extent of organization, we performed a high-resolution large-eddy simulation (LES) parameter study. We varied the horizontal wind speed, the surface heat capacity, the solar zenith and azimuth angles, and radiative transfer parameterizations (1-D and 3-D). As a quantitative measure we introduce a simple algorithm that provides a scalar quantity for the degree of organization and the alignment. We find that, even in the absence of a horizontal wind, 3-D radiative transfer produces cloud streets perpendicular to the sun's incident direction, whereas the 1-D approximation or constant surface fluxes produce randomly positioned circular clouds. Our reasoning for the enhancement or reduction of organization is the geometric position of the cloud's shadow and its corresponding surface fluxes. Furthermore, when increasing horizontal wind speeds to 5 or 10 m s(-1), we observe the development of dynamically induced cloud streets. If, in addition, solar radiation illuminates the surface beneath the cloud, i.e., when the sun is positioned orthogonally to the mean wind field and the solar zenith angle is larger than 20 degrees, the cloud-radiative feedback has the potential to significantly enhance the tendency to organize in cloud streets. In contrast, in the case of the 1-D approximation (or overhead sun), the tendency to organize is weaker or even prohibited because the shadow is cast directly beneath the cloud. In a land-surface-type situation, we find the organization of convection happening on a timescale of half an hour. The radiative feedback, which creates surface heterogeneities, is generally diminished for large surface heat capacities. We therefore expect radiative feedbacks to be strongest over land surfaces and weaker over the ocean. Given the results of this study we expect that simulations including shallow cumulus convection will have difficulties producing cloud streets if they employ 1-D radiative transfer solvers or may need unrealistically high wind speeds to excite cloud street organization. |
领域 | 地球科学 |
收录类别 | SCI-E |
WOS记录号 | WOS:000414949200003 |
WOS关键词 | LARGE-EDDY SIMULATION ; PLANETARY BOUNDARY-LAYER ; SURFACE IRRADIANCE ; TENSTREAM SOLVER ; LAND-SURFACE ; APPROXIMATION ; HETEROGENEITY ; ATMOSPHERE ; MODELS ; IMPACT |
WOS类目 | Environmental Sciences ; Meteorology & Atmospheric Sciences |
WOS研究方向 | Environmental Sciences & Ecology ; Meteorology & Atmospheric Sciences |
引用统计 | |
文献类型 | 期刊论文 |
条目标识符 | http://119.78.100.173/C666/handle/2XK7JSWQ/16158 |
专题 | 地球科学 |
作者单位 | Ludwig Maximilian Univ Munchen, Meteorol Inst, LMU, Munich, Germany |
推荐引用方式 GB/T 7714 | Jakub, Fabian,Mayer, Bernhard. The role of 1-D and 3-D radiative heating in the organization of shallow cumulus convection and the formation of cloud streets[J]. ATMOSPHERIC CHEMISTRY AND PHYSICS,2017,17(21). |
APA | Jakub, Fabian,&Mayer, Bernhard.(2017).The role of 1-D and 3-D radiative heating in the organization of shallow cumulus convection and the formation of cloud streets.ATMOSPHERIC CHEMISTRY AND PHYSICS,17(21). |
MLA | Jakub, Fabian,et al."The role of 1-D and 3-D radiative heating in the organization of shallow cumulus convection and the formation of cloud streets".ATMOSPHERIC CHEMISTRY AND PHYSICS 17.21(2017). |
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