Spatiotemporal variability in convective cells and their thermodynamic and aerosol environments during TAMU TRACER

Description

In June-September 2022, a team from Texas A&M University (TAMU) conducted mobile radiosonde and aerosol measurements as part of the Tracking Aerosol Convection Interactions Experiment (TRACER) field campaign. Given the proximity of the Gulf of Mexico and Galveston Bay to the study region, sea- and bay-breeze circulations are ubiquitous features of this region during the study period, and they often serve as a focus for convection initiation. Moreover, distinct air masses on either side of these mesoscale boundaries are likely to contain different aerosol and meteorological characteristics that may influence convection. Thus, the specific goal of the mobile TAMU team was to sample both the meteorological and aerosol variability across mesoscale air masses, using a suite of radiosondes, aerosol, cloud condensation nuclei (CCN) and ice nucleating particle (INP) instruments similar to the those at the fixed-site DOE facilities. 

In this poster, we briefly review our deployment strategy, summarize the available radiosonde, aerosol and cloud nucleation data, and present new results documenting the variability in convective cell environments as well as radar-derived cell characteristics as a function of their background airmass. First, early and late afternoon differences in the thermodynamic conditions (e.g., CAPE, CIN, precipitable water) in continental (inland of the sea-breeze front), maritime (on the coastal side of the sea-breeze front), and outflow (from ongoing or previous convection) air masses are compared between the TAMU measurements and DOE ARM sites.  Next, we compare the characteristic surface and boundary layer concentrations of aerosols with the propensity to activate as CCN or INP with the conditions present within these air masses. Finally, radar observations from the National Weather Service S-band WSR-88D and the DOE C-band Scanning ARM Precipitation Radar (CSAPR2) are used to compare convective cell attributes as a function of their parent airmass (continental, maritime, outflow, or along the sea-breeze front). WSR-88D measurements are used to provide a climatology of cell attributes (e.g., durations, maximum echo top heights, cell area, maximum reflectivity, time to transition) in each air mass. The CSAPR2 was run in a novel cell-tracking mode featuring targeted PPI sectors and RHIs, which we use to provide and compare vertical profiles of reflectivity and polarimetric variables (e.g., differential reflectivity columns) for a subset of the well-sampled cells. We will also describe our plans for the remainder of this project to isolate the  relative importance of thermodynamic versus aerosol variability on observed differences in convection across air masses.