Modeling Mesoscale Convective Systems in a Highly Simplified Environment

Xiping Zeng Morgan State University
NASA GSFC NASA GSFC
Robert Houze University of Washington

Category: Modeling

Working Group: Cloud Life Cycle

A three-dimensional cloud-resolving model (CRM) is used to simulate mesoscale convective systems (MCSs) in a highly simplified environment, addressing how cloud microphysics, vertical wind shear, and radiation impact the cloud organization in radiative-convective equilibrium (RCE). Sensitivity experiments reveal that the clouds at RCE become aggregated in two forms: (1) cloud envelopes that span ~100 km wide and propagate at ~4 m/s and (2) convective lines that are embedded in the former. These two forms are associated with cloud microphysics (e. g., ice processes) and vertical wind shear, respectively. Besides, the prevalence in modeled cloud envelope as well as observed MCS suggests that tropical cloud systems favor mesoscale too, which is beyond the Bjerknes theory that conditional instability favors the smallest possible scale of cumulus clouds.

This poster will be displayed at ASR Science Team Meeting.

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