A tendency equation for evaporation in a growing convective boundary layer (CBL) is derived. This derivation allows for a process-based decomposition in which each involved land-atmosphere feedback accounts for one term in the equation. Therefore, the influence of entrainment processes on evaporation can be quantified and separated from other land-atmosphere feedbacks. An expression for equilibrium evaporation is derived from the tendency equation and it is investigated how the magnitude of the equilibrium evaporation and the involved time scales depend on the land-atmosphere feedbacks. It is shown that entrainment can enhance the equilibrium evaporation significantly. In addition, the relative enhancement explains very well the characteristic Priestley-Taylor coefficient of 1.26 over well-watered surfaces. Entrainment increases the characteristic time scale of the system if the evaporation exceed
|Title of host publication||EMS Annual Meeting Abstracts, Eighth Annual Meeting of the European Meteorological Society, Amsterdam, 29 September-3 October 2008|
|Publication status||Published - 2008|
|Event||Eighth Annual Meeting of the European Meteorological Society - |
Duration: 29 Sep 2008 → 3 Oct 2008
|Conference||Eighth Annual Meeting of the European Meteorological Society|
|Period||29/09/08 → 3/10/08|
van Heerwaarden, C. C., & Vilà-Guerau de Arellano, J. (2008). A tendency equation for evaporation over a convective boundary layer. In EMS Annual Meeting Abstracts, Eighth Annual Meeting of the European Meteorological Society, Amsterdam, 29 September-3 October 2008 (pp. A-00148). EMS.