Moist Convective Dynamics Research

Convective clouds in the atmosphere are a critical component of many weather phenomena, including high impact weather like hurricanes and severe thunderstorms, and are also a key driver of climate. Continued advances in computing power, including NCAR’s Cheyenne supercomputer, have allowed unprecedented fidelity in simulating convective clouds using research models to address important uncertainties in the dynamics of convective clouds. Combined with recent theoretical work, these simulations have shown how the structure of convective clouds often consist of a series of rising bubbles of buoyant air, or thermals (referred to as a thermal of updraft “chain”). An example of this structure from a model simulation is shown in the figure, with individual thermals in the chain illustrated by black circles. This structure has important implications for how convective clouds entrain and mix with surrounding environmental air, which strongly influences their properties. In addition to improving understanding of the fundamental behavior of convective clouds, this research is directly relevant to the development of convection parameterization schemes in weather and climate models.

Idealized 3D LES (dx = dz = 100m) of a growing deep convective cloud. Color contours show cloud water mixing ratio, blue and red lines are perturbation pressure, and arrows indicate flow vectors.
Figure: Idealized 3D LES (dx = dz = 100m) of a growing deep convective cloud. Color contours show cloud water mixing ratio, blue and red lines are perturbation pressure, and arrows indicate flow vectors.

This research is being carried out in collaboration with the Naval Postgraduate School, Pacific Northwest National Laboratory, and Brookhaven National Laboratory. Sponsors include the Department of Energy Atmospheric System Research DE-SC0016476, United Arab Emirates Research Program for Rain Enhancement Science.