气候变化领域集成服务门户(CCPortal): Droplet size distribution, liquid watercontent and water input of the seasonally variable, nocturnal fog in the Central Namib Desert

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DOI	10.1016/j.atmosres.2021.105765
	Droplet size distribution, liquid watercontent and water input of the seasonally variable, nocturnal fog in the Central Namib Desert
	Spirig R.; Vogt R.; Feigenwinter C.
发表日期	2021
ISSN	0169-8095
卷号	262
英文摘要	In the aridCentral Namib desert, rainfall is rare, but fog frequently occurs at night and exhibits a seasonal pattern. We deployed an eddycovariance setup at two different inland locations, namely Gobabeb and Vogelfederberg. The setup consisted of a cloud droplet probe and at times of up to two sonic anemometer-thermometers. It was deployed for 1.5 years, collecting data during more than 150 fog events at either one of the sites. We characterize the different fog regimes at the two stations with co-located measurements of visibility, fog collector mesh precipitation by fog collectors, and non-rainfall water input by microlysimeters for selected periods. At similar levels of visibility, fog collector mesh precipitation at Vogelfederberg is generally higher, likely due to its higher elevation and exposed location. Fog events appear front-like with a decrease of visibility and an increase of droplet numbers above 10 μm and the associated liquid water content. Fog events regularly lasted 6 h, with the first two to three hours exhibiting higher liquid water content. The droplet distribution, especially droplets above 20 μm, and thus liquid water content varied in numbers between the locations. Liquid water content correlates with fog collector mesh precipitation at Gobabeb, where the droplet distribution spans the whole resolved spectrum. While liquid water flux was bi-directional, the net sum was still a net gain for the surface. We found only a low correlation between liquid water flux and non-rainfall water input, which demonstrates that the liquid water flux can only partially connect the measured input in the fog collectors and the microlysimeters despite similar values. We therefore presume that drizzle, that is droplets out of the CDP sampling range, may play a role in the Central Namib fog, especially when fog is intermittent as fog deposition in microlysimeters continues when no droplets of the respective size range are present near the ground. Furthermore, the contrast of higher fog collector mesh precipitation at Vogelfederberg compared to Gobabeb despite lower liquid water content is potentially a result of the more numerous small droplets as a consequence of the interception with the upper parts of the stratus. © 2021 The Authors
英文关键词	Central Namib; Cloud droplet probe; Fog; Fog droplets; Liquid water content of fog
来源期刊	Atmospheric Research
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/236632
作者单位	Departmentof Environmental Sciences, Klingelbergstrasse 27, University of Basel, Basel, 4056, Switzerland
推荐引用方式 GB/T 7714	Spirig R.,Vogt R.,Feigenwinter C.. Droplet size distribution, liquid watercontent and water input of the seasonally variable, nocturnal fog in the Central Namib Desert[J],2021,262.
APA	Spirig R.,Vogt R.,&Feigenwinter C..(2021).Droplet size distribution, liquid watercontent and water input of the seasonally variable, nocturnal fog in the Central Namib Desert.Atmospheric Research,262.
MLA	Spirig R.,et al."Droplet size distribution, liquid watercontent and water input of the seasonally variable, nocturnal fog in the Central Namib Desert".Atmospheric Research 262(2021).