Kalahari Heat Low
| Kalahari Heat Low (Kalahari Thermal Low) | |
|---|---|
 Location of the Kalahari Desert where the Heat Low forms | |
| Area of occurrence | Southern Africa |
| Season | September–March (austral summer) |
| Effect | Rainfall variability, droughts, atmospheric circulation |
The Kalahari Heat Low (KHL), also known as the Kalahari Thermal Low, is a semi‑permanent low‑pressure system that develops over the interior of Southern Africa during the austral summer months. It is driven by intense surface heating over the Kalahari Desert and surrounding plateau, and plays a critical role in regional climate, rainfall variability, and drought dynamics.[1]
Structure and dynamics
The Kalahari Heat Low is characterized by:
- Strong surface heating over the semi‑arid Kalahari plateau.
- Low‑level cyclonic circulation with ascent between 800 and 600 hPa.
- Subsidence aloft, producing a “heat dome” effect that suppresses convection.[2]
The system exhibits strong diurnal variability, with maximum ascent occurring around midnight and peak low‑level winds in the early morning hours.[1]
Seasonal variability
- The KHL typically initiates in September over Angola and migrates southward into Namibia and Botswana by November–March.
- It dissipates in March, coinciding with the end of the rainy season.
- Its strength and position are closely linked to the Intertropical Convergence Zone (ITCZ) and the Angola Low.[3]
Climatic importance
The Kalahari Heat Low is a key driver of rainfall variability in southern Africa:
- Warm phases induce subsidence and drought conditions.
- Cooler phases allow moisture convergence and convection, increasing rainfall.
- Recent studies show a 175% increase in strong heat low days between 1960–1989 and 1990–2019, consistent with regional warming trends.[1]
See also
References
- ↑ 1.0 1.1 1.2 Attwood, Kitty; Washington, Richard; Munday, Callum (2024). "The Southern African Heat Low: Structure, Seasonal and Diurnal Variability, and Climatological Trends". Journal of Climate. 37 (10). doi:10.1175/JCLI-D-23-0522.1.
- ↑ "The representation of the Kalahari thermal low and its induced circulations". University of Cape Town. Retrieved 30 December 2025.
- ↑ "Climate research in the Kalahari Desert: the KAPEX field campaign". University of Oxford. Retrieved 30 December 2025.
External links
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