Simulating cloud ensembles using large-scale forcing from the DYNAMO sounding array

We will present preliminary results from cloud-resolving simulations of convective ensembles during DYNAMO using the WRF model. The model is forced in two ways: 1). The conventional method, in which large-scale vertical velocity derived from the sounding array is used to compute large-scale vertical advective tendencies, as done in many previous studies. The purpose here is to show the ensemble characteristics of simulated clouds in the Indian Ocean, as compared to previous studies using forcing observed at TOGA COARE, and to validate our numerical model, including its dynamics and physics. 2). The Weak Temperature Gradient (WTG) method. Here we use WTG to derive large scale vertical velocity interactively, while time varying tropospheric temperature anomalies from DYNAMO sounding array are imposed. As we are focusing on time varying behavior of cloud ensembles for specific observed time periods, our study differs from past studies that used WTG to simulate statistically steady properties of convection under time-independent forcings. Our preliminary results suggest that the WTG method may be able to capture variations of surface rainfall on synoptic time scales, but not higher-frequency variations.