An intensive observation period was conducted in September 2017 in the central Namib, Namibia, as part of the project Namib Fog Life Cycle Analysis (NaFoLiCA). The purpose of the field campaign was to investigate the spatial and temporal patterns of the coastal fog that occurs regularly during nighttime and morning hours. The fog is often linked to advection of a marine stratus that intercepts with the terrain up to 100 km inland. Meteorological data, including cloud base height, fog deposition, liquid water path, and vertical profiles of wind speed/direction and temperature, were measured continuously during the campaign. Additionally, profiles of temperature and relative humidity were sampled during five selected nights with stratus/fog at both coastal and inland sites using tethered balloon soundings, drone profiling, and radiosondes. This paper presents an overview of the scientific goals of the field campaign; describes the experimental setup, the measurements carried out, and the meteorological conditions during the intensive observation period; and presents first results with a focus on a single fog event.

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Dolueg is a two-component framework to dynamically display time series. It serves as outreach to other researchers and the local public, educational resource and quality control tool. The first component is a set of Python functions. These create different types of visualisation with meta information about the data in the zoomable, modern SVG format. The second component is a simple but highly customizable website, that groups these figures according to the displayed data. We provide the code in two separate repositories on GitHub for interested parties including more detailed instructions for the installation.

<p>Regular, nocturnal fog is a defining and seasonally varying feature in the Namib desert. Historical observations were limited to the binary measure of fog occurrence and the concurrent fog water input is quantified only since 2014 via the FogNet using Juvik fog collectors. This installation opened new avenues of research such as the efficiency of the transport mechanism, sampling and spatial variation thereof. An eddy covariance setup of a cloud droplet probe and collocated sonic(s) was installed in turns at the two FogNet stations Vogelfederberg (23.10°S, 15.03°E, 515 m above sea level) and Gobabeb (23.56°S, 15.04°E, 406 m above sea level) for 2 years in the frame of the Namib Fog Life Cycle Analysis Field Measurements (NaFoLiCA-F) project. With this setup, we gathered duration, droplet size distribution, droplet concentration, liquid water content, turbulent liquid water flux and the fog water input via the Juvik fog collector with a total of over 150 fog events. We found that fog appears suddenly and front-like as seen by an increase of droplet numbers by several magnitudes and dissolves more gradually towards the morning. All droplet classes of the resolved range of 2 to 50 µm are present, but at the Vogelfederberg with around 2 to 3 times larger fog water input, the mean and median of the distribution are lower due to comparably fewer large droplets. Liquid water fluxes at both sites resulted in a net gain for the surface but the spatial discrepancy between fog water input recorded by fog collectors and the liquid water content indicates that drizzle, i.e. droplets outside the resolved range, may contribute to the larger total water deposition at Vogelfederberg.</p>