ESCAPE

ESCAPE (Experiment of Sea Breeze Convection, Aerosols, Precipitation, and Environment) identified two aircraft platforms to replace the NSF/NCAR C-130 aircraft. This experiement was carried out by the NRC Convair-580 from the National Research Council (NRC) Canada and the SPEC LearJet-35A. The experiment took place between May 30 to June 30, 2022. Project operations were based at the Sugar Land Regional Airport in the Greater Houston area.

Convective clouds play an important role in the Earth’s climate system as a driver of large-scale circulations and a primary mechanism for the transport of heat, moisture, aerosols, and momentum throughout the troposphere. Despite their climatic importance, multi-scale models continue to have persistent biases produced by an inadequate representation of convective clouds. To increase our understanding of convective cloud lifecycles and aerosol-convection interactions, we proposed a field experiment in the Houston area that used high-definition radar-based observations and the NSF/NCAR C-130 to track the lifecycle of a large number of convective cells for the following purposes:

(i) Characterizing the spatial and temporal scale of convective cloud kinematic and microphysical processes using rapid-scan, polarimetric Doppler radar observations

(ii) Quantifying environmental thermodynamic and kinematic controls on convective lifecycle properties under different aerosol conditions

(iii) Increase our process-level understanding on the relative role of aerosols, meteorology and surface forcing in determining the lifecycle of convective clouds using integrated modeling-observations activities.

The Houston, TX region is an optimal location for targeted studies of aerosol-convection interactions owing to frequently developing isolated deep convection, and the interaction of onshore flow and sea-breeze convection with a range of aerosol conditions associated with Houston’s urban and industrial emissions. The campaign focused on the characterization of convective cloud properties, lifecycles, and their environments with an emphasis on cloud-scale dynamics and microphysics, particularly in the updraft/mixed-phase region under different aerosol loading conditions. The observational analysis focused on the differences in these characteristics under varying environmental forcing, surface conditions, wind direction and aerosol regimes. An integrated modeling component was also proposed and used derived forcing datasets to simulate deep convective cases at cloud-resolving model (CRM) scales. The main target was to identify cases with observed differences in isolated convective microphysics where there was a significant aerosol perturbation within a relatively uniform thermodynamic environment with winds from similar directions. These cases were then used to evaluate our ability to simulate these signatures using CRMs.