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Structure, modulation and impacts of southeastern Africa's diurnal convection.
- Source :
-
Theoretical & Applied Climatology . Jun2024, Vol. 155 Issue 6, p4851-4862. 12p. - Publication Year :
- 2024
-
Abstract
- This study explores the structure, modulation, and impacts of the mean diurnal climate across southeast Africa using high-resolution hourly reanalysis and satellite rainfall. This research was motivated by upward trends in diurnal temperature range and vegetation index over the Drakensberg escarpment. Statistical analysis identified a land-sea rainfall dipole pattern associated with diurnal airflows. Point-to-field regressions (Oct–Mar 2000–2023) found that sea breeze-driven convection is underpinned by 'col' airflow between adjacent sub-tropical low-pressure cells (30°S, 20°E/22°S, 37°E) and a weak mid-latitude anticyclone (40°S, 10°E). Diurnal residual and case study analysis demonstrate an ~ 6-m/s sea breeze penetrating ~ 200 km inland during the day, as part of an over-turning zonal circulation. Land > sea rainfall during summer is initiated by temperature gradients ∂T/∂x ~ 5 °C at 29°S, 31°E and convergence in the afternoon ∂U/∂x ~ − 4 × 10−5 s−1. Further inland (29°S, 26°E) a 1007-hPa thermal low and counter-clockwise rotating airflows interact with the incoming sea breeze. Together these contribute to evening rainfall ~ 30 mm over the Drakensberg escarpment. The drivers of diurnal rainfall show little response to global climate variability, and help sustain water resources during multi-year dry spells over southeastern Africa. [ABSTRACT FROM AUTHOR]
- Subjects :
- *RAINFALL
*AIR flow
*SEA breeze
*WATER supply
*CLIFFS
Subjects
Details
- Language :
- English
- ISSN :
- 0177798X
- Volume :
- 155
- Issue :
- 6
- Database :
- Academic Search Index
- Journal :
- Theoretical & Applied Climatology
- Publication Type :
- Academic Journal
- Accession number :
- 178459689
- Full Text :
- https://doi.org/10.1007/s00704-024-04885-y