Entrainment Rate of Deep Convection over the Amazon
Authors
Usama Anber — Brookhaven National Laboratory
Scott Giangrande — Brookhaven National Laboratory
Michael Jensen — Brookhaven National Laboratory
Category
Convective clouds, including aerosol interactions
Description
High-Resolution model simulations of convective events over the Amazon basin are analyzed to directly compute entrainment and detrainment rates. The rates are computed from the analytical expression of continuity equation applied over convective cloudy air sampled conditionally. Entrainment is then compared against that estimated from cloud buoyancy, cloud height, and relative humidity usually used in parameterization schemes. The results suggest that the only relationship that holds robustly is that with the inverse convective updraft vertical velocity. The mixing time scale over which the relationship holds monotonically decreases with the model resolution. When applying this time scale to the observed radar vertical velocity obtained from the GoAmazon field campaign, it yields entrainment rate that agrees very well with the computed one.
