ANALYSES OF CUMULUS MIXING USING ASR AIRCRAFT OBSERVATIONS AND LES SIMULATIONS

The goal of the proposed research is to better understand mixing in cumulus clouds, which has broad implications to cumulus dynamics and their representations in Global Climate Models (GCMs). We propose to carry out detailed analyses of aircraft measurements and the associated surface and atmospheric profile measurements from the recent Atmospheric System Research (ASR) field campaigns. The analyses will be supported by Large Eddy Simulations (LES) combined with Lagrangian tracking, and in turn help to evaluate the LES. We will focus on specific issues including two-point mixing and buoyancy sorting, the extent of homogenization of entrained air parcels within the updrafts, dilution of the cloud core, the probability distribution of the cloud-environment mixture, characteristics of the subsiding shells, and how these characteristics depend on the types of cumuli and the conditions of their environment. We expect this research to improve our understanding of cumulus mixing, which forms the foundation for physically based parameterizations of cumulus convection,

convection

The rising of warm air and the sinking of cool air. Convection can cause local breezes, winds, and thunderstorms.

Source: NASA earth observatory Source

and significantly enhance the scientific return of the ASR aircraft campaigns. The representation of clouds and convection in GCMs remains a main contributor to the high degree of uncertainty in climate change

climate change

A change in the average conditions — such as temperature and rainfall — in a region over a long period of time.

Source: NASA Climate Kids Source

projections. This research will therefore support the accomplishment of the office of Biological and Environmental Research Earth and Environmental Systems Science's Division’s long-term measure of scientific advancement.