Is There Enhanced Evaporation In Surface-Exposed Fractures Due To Convection Of Water Vapor? Academic Article uri icon

abstract

  • Diffusive fluxes limit the potential amount of evaporation from surface-exposed fractures and other discontinuities crossing the land surface. However, if density differences between the air above a fracture and the moist air within the fracture voids exist, convective flux might be developed. If so, evaporation could increase by up to several orders of magnitude, dependent on temperature differences and the size of the aperture. Theoretical calculations suggest that under typical high deserts conditions convection is likely to occur during the night while diffusion is likely to control evaporation from fractures during the day. Field experiment carried out in the Negev desert of Israel showed that the amount of salts accumulated within a fracture in six months is much higher than what could be explained by diffusion alone. This further support the existence of additional mechanism that enhances …

publication date

  • January 1, 2005