Thermal structure of the atmospheric boundary layer over the South African Mpumalanga Highveld

ABSTRACT: This study deals with the parametrisation of the vertical thermal structure of the atmospheric boundary layer up to 100 m above ground level over the industrial Mpumalanga Highveld in South Africa. Potential air temperatures were calculated by similarity theory based algorithms. The results were unsatisfactory for stable and unstable conditions in comparison to the measured data of a 96 m tower. A higher accuracy was achieved with algorithms constructed by subjecting the measured data to multiple regression analysis. Potential air temperatures at various levels up to 96 m above ground level were calculated with average errors of 0.82°C for stable conditions, 0.63°C for unstable early-morning and late-afternoon conditions and 0.37°C for unstable daytime conditions. The accuracy was sufficient to assess the thermal atmospheric stability of the boundary layer up to 100 m above ground level.