Wet‐Bulb Temperature Extremes Locally Amplified by Wet Soils
Abstract Wet‐bulb temperature extremes (WTEs) occur due to a combination of high humidity and temperature, and are hazardous to human health. Alongside favourable large‐scale conditions, surface fluxes play an important role in WTEs; yet, little is known about how land surface heterogeneity influenc...
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| Main Authors: | , , , , , |
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| Format: | Article |
| Language: | English |
| Published: |
Wiley
2025-04-01
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| Series: | Geophysical Research Letters |
| Subjects: | |
| Online Access: | https://doi.org/10.1029/2024GL112467 |
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| Summary: | Abstract Wet‐bulb temperature extremes (WTEs) occur due to a combination of high humidity and temperature, and are hazardous to human health. Alongside favourable large‐scale conditions, surface fluxes play an important role in WTEs; yet, little is known about how land surface heterogeneity influences them. Using a 10‐year, pan‐African convection‐permitting model simulation, we find that most WTEs have spatial extents <2,000 km2. They occur preferentially over positive soil moisture anomalies (SMA) typically following rainfall. The wet‐bulb temperature is locally amplified by 0.5–0.6°C in events associated with smaller‐scale SMA (50 km across) compared to events with larger‐scale SMA (300 km across). A mesoscale circulation, resulting from stronger spatial contrasts of sensible heat flux, more efficiently concentrates moist, warm air in a shallower boundary layer. This mechanism could explain the underestimation of peak Twb values in coarser‐resolution products. The role of antecedent SMA from recent rainfall may help issue localized early warnings. |
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| ISSN: | 0094-8276 1944-8007 |