Investigation of the Vertical Geometry of Low Level Clouds in the Namib Desert

Abstract

This study comprehensively investigates the vertical geometry of low-level clouds in the Namib desert. Using ceilometer measurements and meteorological station observations, a precise determination of cloud-base height and the separation of low-level stratus and fog is performed.The Namib Desert, known for hyper-arid conditions and frequent cloudiness, presents an intriguing environment for the study of low-level clouds and their vertical geometry. Fog (ground-touching low-level clouds), a common atmospheric phenomenon in the Namib Desert, is influenced by the interplay of coastal upwelling and spatial temperature differences. Differentiation of fog from other low-level clouds and understanding cloud dynamics are crucial, as fog impacts the water balance in this arid region. Here, ceilometer measurements of cloud base altitude are analyzed and combined with local station measurements with the aim of developing a statistical model to robustly predict cloud base altitude.Initial results suggest a robust correlation between the cloud base height and surface relative humidity, as well as other meteorological variables. This finding proves beneficial for utilizing meteorological parameters such as the lifted condensation level as a surrogate for cloud-base height. The outcomes of this study hold significance for modeling of satellite-based fog probability product and ecological studies.