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Most fog detection from space cannot differentiate fog and low stratus clouds, and cannot estimate fog deposition. This study assessed the feasibility of using spaceborne lidar observations from the Cloud‐Aerosol Lidar and Infrared Pathfinder Satellite Observation (CALIPSO) in fog detection and estimation. We tested the method in the central Namib Desert, Namibia, where frequent fog events occur and fog observations are available. Results showed the CALIPSO backscatter signal at 532 nm can differentiate low clouds and fog due to its high‐resolution vertical profiles. Backscatter signals during fog events were significantly higher than those during non‐fog periods. The R2 between backscatter signals and fog observations was 0.85. Moreover, the backscatter signal was also sensitive to relative humidity variation (R2 = 0.66). These results indicate that the CALIPSO data are feasible to estimate fog occurrence and deposition, providing a new perspective for space‐based fog studies. Plain Language Summary: Fog is an important water resource for ecosystem productivity and functions in many dryland regions. Most fog detection from space cannot differentiate fog and low stratus clouds, and cannot estimate fog deposition. The spaceborne lidar measurements from Cloud‐Aerosol Lidar and Infrared Pathfinder Satellite Observation with high‐resolution vertical profiles provide a possibility to differentiate fog and low stratus clouds from space. A significant correlation was shown between spaceborne lidar signals and ground fog observations. Our findings can help investigate fog formation mechanisms as well as improve the capacity and accuracy of satellite‐based fog detection. Key Points: The first use of spaceborne lidar measurements to retrieve fog depositionThe Cloud‐Aerosol Lidar and Infrared Pathfinder Satellite Observation lidar observations with high‐resolution vertical profiles can differentiate fog and low cloudsThe spaceborne lidar measurements reflect the spatial features of fog and clouds, and can assist to investigate fog formation and identify fog types [ABSTRACT FROM AUTHOR]

Soil nematodes are fundamentally aquatic animals, requiring water to move, feed, and reproduce. Nonetheless, they are ubiquitous in desert soils because they can enter an anhydrobiotic state that allows them to persist when water is biologically unavailable. In the hyper‐arid Namib Desert of Namibia, rain is rare, but fog routinely moves inland from the coast and supports plant and animal life. Very little is understood about how this fog may affect soil organisms. We investigated the role of fog moisture in the ecology of free‐living, soil nematodes across an 87‐km fog gradient in the gravel plains of the Namib Desert. We found that nematodes emerged from anhydrobiosis and became active during a fog event, suggesting that they can utilize fog moisture to survive. Nematode abundance did not differ significantly across the fog gradient and was similar under shrubs and in interplant spaces. Interplant soils harbor biological soil crusts that may sustain nematode communities. As fog declined along the gradient, nematode diversity increased in interplant soils. In areas where fog is rare, sporadic rainfall events can stimulate the germination and growth of desert ephemerals that may have a lasting effect on nematode diversity. In a 30‐day incubation experiment, nematode abundance increased when soils were amended with water and organic matter. However, these responses were not evident in field samples, which show no correlations among nematode abundance, location in the fog gradient, and soil organic matter content. Soil nematodes are found throughout the Namib Desert gravel plains under a variety of conditions. Although shown to be moisture‐ and organic matter‐limited and able to use moisture from the fog for activity, variation in fog frequency and soil organic matter across this unique ecosystem may be biologically irrelevant to soil nematodes in situ. [ABSTRACT FROM AUTHOR]

Fog is an important water source for many ecosystems, especially in drylands. Most fog‐vegetation studies focus on individual plant scale; the relationship between fog and vegetation function at larger spatial scales remains unclear. This hinders an accurate prediction of climate change impacts on dryland ecosystems. To this end, we examined the effect of fog on vegetation utilizing both optical and microwave remote sensing‐derived vegetation proxies and fog observations from two locations at Gobabeb and Marble Koppie within the fog‐dominated zone of the Namib Desert. Significantly positive relationships were found between fog and vegetation attributes from optical data at both locations. The positive relationship was also observed for microwave data at Gobabeb. Fog can explain about 10%–30% of variability in vegetation proxies. These findings suggested that fog impacts on vegetation can be quantitatively evaluated from space using remote sensing data, opening a new window for research on fog‐vegetation interactions. Plain Language Summary: This study presents the first observed relationships between fog and vegetation function using satellite remote sensing data. Significant correlations were found between fog and satellite‐derived vegetation indices at two study sites within the Namib Desert. These findings suggested that satellite data can be used to assess and quantify the impacts of fog on vegetation at large spatial scales. Key Points: The positive impact of fog on vegetation is first observed using satellite remote sensing dataFog can explain 10%–30% of variability in vegetation proxiesOptical and microwave remote sensing data showed continuous positive impact of fog on vegetation [ABSTRACT FROM AUTHOR]