Sensitivity of deep convection updrafts and microphysics to thermodynamic and aerosol environments in idealized simulations using TRACER observations

Description

During the Department of Energy (DOE) Tracking Aerosol Convection interactions ExpeRiment (TRACER), isolated convection was often initiated and organized in sea- and bay-breeze air masses with different aerosol and meteorological characteristics that may influence convective cell evolution. To fully sample the variability in both meteorological conditions and aerosols across the sea breeze front, Texas A&M University (TAMU) deployed a mobile radiosonde unit and the new Rapid Onsite Atmospheric Measurement Van (ROAM-V) for aerosol, cloud condensation nuclei (CCN), and ice nucleating particle (INP) sampling on select enhanced operations days during TRACER.  Combining the DOE Atmospheric Radiation Measurements (ARM) Mobile Facility (AMF1) fixed site measurements with the mobile TAMU measurements, meteorological and aerosol environments were sampled simultaneously in the maritime and continental air masses across the sea breeze front, allowing us to capture the thermodynamic and aerosol profile of the inflow environment of convective cells within a given airmass.

This poster highlights results from a suite of six idealized WRF simulations for an isolated convection case using representative meteorological base states based on TAMU and AMF1 measured thermodynamic and kinematic profiles from the respective maritime and continental sides of the sea breeze front.  For the control simulation, each meteorological base state is paired with the corresponding measured aerosol concentration and size distribution, vertical aerosol profile retrieved from the surface aerosol and lidar observations, and measured aerosol hygroscopicity.  To understand the relative sensitivity to realistic aerosol distributions and the background meteorological environments, we interchange the aerosol size distributions and profiles with two other measured profiles either from the same or different airmass. In particular, we focus the analysis on updraft characteristics, microphysical tendencies, and precipitation processes related to different aerosol-convection interaction mechanisms in simulated isolated convection. Preliminary results show that despite relatively small differences in the maritime and continental thermodynamic environments, the thermodynamic environment effects are generally larger than aerosol effects. However, the sign of the aerosol effects on updrafts, microphysics, and precipitation within a given airmass appears to not only be sensitive to aerosol concentrations and size distributions, but also quite sensitive to the aerosol hygroscopicity.