Effects of atmospheric stability conditions on heat fluxes from small water surfaces in (semi-)arid regions |
| |
Authors: | Ali Abbasi Frank Ohene Annor Nick van de Giesen |
| |
Affiliation: | 1. Faculty of Civil Engineering and Geosciences, Water Resources Section, Delft University of Technology, Delft, The Netherlands;2. Faculty of Engineering, Civil Engineering Department, Ferdowsi University of Mashhad, Mashhad, Iran;3. Civil Engineering Department, Kwame Nkrumah University of Science and Technology, Kumasi, Ghana |
| |
Abstract: | Atmospheric stability conditions over the water surface can affect the evaporative and convective heat fluxes from the water surface. Atmospheric instability occurred 72.5% of the time and resulted in 44.7 and 89.2% increases in the average and maximum estimated evaporation, respectively, when compared to the neutral condition for a small shallow lake (Binaba) in Ghana. The proposed approach is based on the bulk-aerodynamic transfer method and the Monin-Obukhov similarity theory (MOST) using standard meteorological parameters measured over the surrounding land. For water surface temperature, a crucial parameter in heat flux estimation from water surfaces, an applicable method is proposed. This method was used to compute heat fluxes and compare them with observed heat fluxes. The heat flux model was validated using sensible heat fluxes measured with a 3-D sonic anemometer. The results show that an unstable atmospheric condition has a significant effect in enhancing evaporation alongside the sensible heat flux from water surfaces. |
| |
Keywords: | evaporation small reservoirs atmospheric boundary layer stability condition semi-arid region |
|
|