A study of tropical convection using a cloud-resolving model with
parameterized large-scale dynamics

Responses of tropical deep convection to external forcing are studied using a cloud-resolving model (CRM) in which large-scale dynamics parameterized with the weak temperature gradient (WTG) approximation. I will present some results on the equilibrated convective responses to change in SST and drying imposed in the free troposphere. Results from CRM are discussed and compared to parameterized convection in a
single column model.

In contrast to these time-independent CRM experiments, the model is also driven by time-dependent field observations, again with large scale dynamics parameterized. In this case, two different dynamical parameterizations are used, WTG and the damped gravity-wave scheme. With appropriate parameters, the model is able to simulate the low-frequency component of the variability with some fidelity to observations. Both WTG and the gravity wave scheme give comparably simulations of precipitation, but the gravity wave scheme gives much better agreement in the large-scale vertical velocity profile.

http://www.columbia.edu/~sw2526/

Host: Marty Singh