Effects of spatial variations of soil moisture and vegetation on the evolution of a prestorm environment: a numerical case study

Abstract

The modeled effects of spatial variations of vegetation and soil moisture included the enhancement of a stationary front oriented northwest-southeast through Grand Island. Prior to sunset, the unstable boundary layer collapses over a zone of cool surface temperature aligned with the observed front and coincident with an observed dry/moist soil boundary. Following the boundary layer collapse, the evolution of the ageostrophic flow exhibits a horizontally differential acceleration that amplifies the isolated upward motion over the frontal boundary. It is shown that the observed stationary front was strongly enhanced by differential heating caused by observed gradients of soil moisture, as acted upon by the vegetation cover. -from Authors