Cloud droplet number concentrations are controlled by both meteorological and microphysical factors. Microphysical factors include aerosol number concentration and composition. This paper examines the importance of microphysical phenomena compared to the sensitivity with respect to parcel updraft velocity in the activation of aerosols to become cloud droplets. Of the compositional (chemical) fa...

This study presents a summary of the properties of deep convective updraft and downdraft cores over the central plains of the United States, accomplished using a novel and now-standard Atmospheric Radiation Measurement Program (ARM) scanning mode for a commercial wind-profiler system. A unique profilerbased hydrometeor fall-speed correction method modeled for the convective environment was adop...

Smoke plume rise is critically dependent on plume updraft structure. Smoke plumes from landscape burns (forest and agricultural burns) are typically structured into “sub-plumes” or multiple-core updrafts with the number of updraft cores depending on characteristics of the landscape, fire, fuels, and weather. The number of updraft cores determines the efficiency of vertical transport of heat and...

A computationally-effective framework is presented that addresses the contribution of subgrid-scale vertical velocity variations in predictions of cloud droplet number concentration (CDNC) in large-scale models. Central to the framework is the concept of a “characteristic updraft velocity”, w, which yields CDNC value representative of integration over a probability density function (PDF) of upd...

Aerosol indirect effects suffer from large uncertainty in climate models and among observations. This study focuses on two plausible factors: regime dependence of aerosol-cloud interactions and the effect of cloud droplet spectral shape. We show, using a new parcel model, that combined consideration of droplet number concentration (Nc) and relative dispersion (ε, ratio of standard deviation to ...

This is a two-part study that addresses the kinematic, microphysical, and electrical aspects of a severe storm that occurred in western Kansas on 29 June 2000 observed during the Severe Thunderstorm Electrification and Precipitation Study (STEPS) field campaign. In this first part, polarimetric and Doppler radar data are used along with a simple particle growth model to examine the evolution of...

This study investigates the effects of aerosols on tropical deep convective clouds (DCCs). A series of largescale, two-dimensional cloud-resolving model simulations was completed, differing only in the concentration of aerosols available to act as cloud condensation nuclei (CCN). Polluted simulations contained more DCCs, wider storms, higher cloud tops, and more convective precipitation domainw...

The Tornado Alley is a geographic region in central United States that is home to the largest number of violent tornadoes in the world. The cloud structures that produce the most violent tornadoes are known as supercells. Being able to predict the formation and the evolution of supercell thunderstorms can improve the forecasting of such severe weather events, thereby preventing human and resour...

Abstract. The number of cloud droplets formed at the base depends on both properties aerosol particles and updraft velocity an air parcel base. As spatial scale updrafts is too small to be resolved in global atmospheric models, commonly parameterised based available turbulent kinetic energy. Here we present alternative methods through parameterising high-resolution large-eddy simulation (LES) r...