Effects of atmospheric stability conditions on heat fluxes from small water surfaces in (semi-)arid regions

Effects of atmospheric stability conditions on heat fluxes from small water surfaces in (semi-)arid regions

Abbasi, A. (TU Delft Water Resources; Ferdowsi University of Mashhad)
Annor, F.O. (TU Delft Water Resources; Kwame Nkrumah University of Science and Technology)
van de Giesen, N.C. (TU Delft Water Resources)

2017-07-04

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.

atmospheric boundary layer
evaporation
semi-arid region
small reservoirs
stability condition

http://resolver.tudelft.nl/uuid:feefcb85-e69e-4350-8a53-6b41a051d342

https://doi.org/10.1080/02626667.2017.1329587

0262-6667

Hydrological Sciences Journal, 62 (9), 1422-1439

Institutional Repository

journal article

© 2017 A. Abbasi, F.O. Annor, N.C. van de Giesen