Investigation of clouds, aerosols, vertical motion, and cold pools during the full convective lifecycle using observations and model simulations from the CACTI field campaign

Investigation of clouds, aerosols,

aerosols

Small particles or droplets, such as wildfire smoke, volcanic gases, or salty sea spray, that float in the air. They are emitted by both natural events and human activities.

Source: NASA Global Climate Change Source

vertical motion, and cold pools during the full convective lifecycle using observations and model simulations from the CACTI field campaign
Kristen L. Rasmussen, Colorado State University (Primary Investigator)
Susan C van den Heever, Colorado State University (Co-Investigator)
Adam Varble, Pacific Northwest National Laboratory (Unfunded Collaborator)

Convective updrafts and downdrafts are fundamental in shaping the vertical and horizontal dimensions of deep convective storms and their microphysical, dynamical and radiative characteristics. Storm vertical motion plays a crucial role in cloud and precipitation formation, latent heating, the amount of water vapor, energy and aerosols that are transported between the surface and upper troposphere, storm intensity and organization, and large-scale atmospheric circulations. These processes, in turn, impact the strength and longevity of updrafts and downdrafts through complex, non-linear feedbacks. In spite of the significant influence of vertical motion in shaping convective storm characteristics and the impacts of 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

on the weather and climate system, accurately predicting convective vertical motion using numerical models remains extremely challenging. This is in part due to our limited understanding of the processes which link storm dynamics, microphysics and surface fluxes,

flux

The amount of some type of particle or energy crossing a unit area per unit time.

Source: NRC Library Source

which affects our capability to accurately represent these relationships in numerical models.

The primary goal of the proposed research is to enhance our understanding of how microphysical and land surface processes impact convective updrafts and downdrafts, and to identify which of these processes are primarily responsible for the biases in high-resolution model predicted vertical velocities within mid-latitude deep convective systems, with the ultimate aim of improving the representation of convection within both high-resolution and global models. The proposed goals will be addressed through the use of observations from the Cloud, Aerosol, and Complex Terrain Interactions (CACTI) and Remote Sensing

remote sensing

The process of detecting and monitoring the physical characteristics of an area by measuring its reflected and emitted radiation at a distance (typically from satellite or aircraft).

Source: USGS Source

of Electrification, Lightning, and Mesoscale/Microscale Processes with Adaptive Ground Observations (RELAMPAGO) field campaigns combined with high-resolution simulations of three convective storm cases across the spectrum of convection initiation over terrain, including upscale growth into a robust MCS,

mesoscale convective system (MCS)

A collection of thunderstorms that act as a system. An MCS can spread across an entire state and may appear as a solid line, a broken line, or a cluster of cells that can last more than 12 hours.

Source: NOAA Source

in which various microphysical processes, surface fluxes, and aerosol concentrations are varied. The project objectives are as follows: (1) Conduct sensitivity tests of microphysical processes to determine which ones have a significant impact on vertical motion; (2) To understand why surface fluxes have an impact on simulated convective updrafts and downdrafts; (3) To increase our knowledge on how combined microphysical and surface fluxes impact cold pools and the associated feedback to convective updrafts; and (4) To determine the impacts of enhanced microphysical parameterization sophistication and grid resolution on the predicted convective updraft biases.

As a result of this research, enhanced process-level understanding will assist the community in addressing convective vertical velocity biases in both high-resolution and global models by virtue of the fact that the development and assessment of global model convective parameterizations rely extensively on vertical velocity statistics from high-resolution models. As such, the proposed research will lead to significant near-term enhancements to both regional and global climate models in representing convective storm structures, dynamics, and life cycles.