Parameterization of Entrainment Rate for Cumulus Clouds with WRF Simulation

By using Weather Research and Forecasting Model (WRF) to simulate a southwest vortex precipitation process, this work studies the correlations between entrainment rate (λ) dynamical parameters in cloud further fit λ. We relate probability density distribution (PDF) parameterization of λ find that greater probability, larger slope logarithmic liner function. The log-linear fitting function decreases for developing enhancing cumulus clouds, which is related increase updraft motion decrease Then, we group clouds according top heights calculate average dynamic parameters, results indicate when only one parameter used, vertical wind velocity (w) more suitable than buoyancy (B) be used functions combing single by principal components regression are compared with two traditional schemes, found obtained our schemes schemes. Because component method takes into account interaction factors entrainment, function, including w B, applied scheme clouds.