In January 2025, a joint team from the University of Oxford and the University of Cape Town headed into the Kalahari to study a fascinating but under-observed atmospheric feature: the Kalahari dryline.
Drylines are sharp boundaries in the atmosphere separating moist and dry air. They’re often linked to the development of convection, and research shows that around 68% of Kalahari drylines are associated with storms forming within 100 km. Despite their significance, there’s been little direct observation of these features in this region — something this project aimed to change.
An early morning radiosonde launch just east of Askham, Northern Cape.
The team carried out observations over three intensive periods, each designed to capture the dryline’s structure and evolution in detail. Two instrumented 4x4 vehicles conducted transects across the dryline, collecting continuous surface data on temperature, humidity, and pressure using Campbell Scientific CR1000 data loggers.
A fixed radiosonde site was operated from Molopo Lodge in Askham, while a second vehicle served as a mobile launch platform. This setup allowed the team to conduct near-simultaneous atmospheric soundings on either side of the dryline — a key part of understanding how it develops and interacts with its environment.
Automatic weather station installation in the Kalahari heat.
A roadside radiosonde release shortly after sunrise, south of Stella, North West province.
This project marks a rare opportunity to capture detailed observations of the Kalahari dryline. The data collected will help improve our understanding of how these features form, persist, and influence convection in semi-arid environments — and contribute to better forecasting in the region.