Grid Adaption and Its Effect on Entrainment in an E–l Model of the Atmospheric Boundary Layer

Abstract

A one-dimensional numerical model KOLUM is introduced that demonstrates the use of continuous dynamic grid adaption in modeling the atmospheric boundary layer. The entrainment rates of KOLUM are compared against recent calibrations for smoke clouds and water clouds derived from large-eddy simulations. The simulations performed with KOLUM support the claim that turbulent kinetic energy?diagnostic length scale (E?l) models overpredict entrainment by smoke and water clouds, independent of the use of grid adaption. The benefits of grid adaption are slight. Curiously, the simulations did not confirm spurious entrainment of E?l models in episodes of subsidence.