In this proposal, we outline a project aimed at combining the various interactions between hydrometeors and small-scale turbulent motions using a unique combination of tools: NASA in-situ observations…

The University of Wyoming, operating as Sponsored Programs, was awarded a $248,320.53 grant from the National Aeronautics and Space Administration (NASA) to conduct research on the interactions between hydrometeors and small-scale turbulent motions. This project will leverage a combination of NASA field campaign data, a unique cloud-in-a-box laboratory setup, direct numerical simulations (DNS), and large eddy simulations (LES) to develop a novel parameterization of the two-way coupling between droplet-turbulence interactions. The goal is to improve the representation of these processes in cloud-resolving models, with the ultimate aim of enhancing the understanding of precipitation rates and cloud structure. This grant does not have a set-aside designation and is set to be completed by February 28, 2023.

In this proposal, we outline a project aimed at combining the various interactions between hydrometeors and small-scale turbulent motions using a unique combination of tools: NASA in-situ observations from select field campaigns, a novel cloud-in-a-box laboratory installation, DNS, and state-of-the-art large eddy simulation (LES) and cloud-resolving model (CRM) simulations. The laboratory experiments, in which high-intensity turbulence conditions are reproduced in a controlled environment, will provide millimeter-resolution information on the air-droplet two-way coupling the conditions of these laboratory experiments (both with regard to the turbulent structure and microphysical characteristics) will be guided by the NASA in-situ field campaign observations. The results of these experiments form a basis by which to validate the DNS work, which will then be used to quantify the impact of the two-way coupling on sedimentation because the one-way effects can be separated in the DNS framework but not in the lab experiments thus, the lab and DNS are complimentary in this work in terms of validating the latter and formulating a parameterization of the two-way coupling observed in the former. This quantification will lead to a parameterization applicable to LES and cloud resolving models (crms), which will be implemented in a bulk microphysics scheme. The novel parameterization will be used in hindcast simulations of the selected NASA field campaign intensive observing periods (iops). Comparison between the model simulations and NASA field campaign data will allow US to examine the effects of droplet-turbulence interaction on precipitation rates and cloud structure at larger scales than can be simulated with DNS.