Determining the Importance of Initiation Mechanism and Background Environment on the Evolution of Deep Convection in Varied Regimes

Description

Results from our prior ASR-funded data collection and analysis during the Tracking Aerosol Convection Interactions Experiment (TRACER) ARM mobile facility deployment (and affiliated TAMU TRACER project) suggest that convection initiated along sea-breeze fronts may evolve to become more intense than that initiated by other mechanisms, and were potentially more sensitive to their initiation mechanism than differences in the background meteorological environment.  This finding has led to a new project by our team that will use ARM observations, both from TRACER and the newly established AMF3 Southeast US (SEUS) atmospheric observatory at Bankhead National Forest in northwest Alabama to determine and quantify the importance of the influence of the initiating mechanism relative to the background environment to subsequent convective cell evolution in varied regimes. To achieve this goal, our project will determine how initial cell area and vertical velocity of nascent convection vary as a function of the initiation mechanism (sea-breeze front, outflow boundary, or boundary layer convective roll/cell) from both TRACER and SEUS AMF3 observations. The dynamical characteristics of the nascent convection (i.e., initial cell width and cloud-top vertical velocity) that are most determinative of subsequent convective cell evolution will be explored and compared to the large-scale ascent, instability, shear, and aerosols in the background environment. Here we present  initial activities towards these goals (focused on TRACER observations) as well as an overview of our planned future activities. Specifically, we will provide initial findings from the implementation of an automated satellite tracking method to identify and quantify area and vertical velocity in nascent convective cells.  We will also present our expanded analysis of the evolution of vertical profiles of aerosols serving as cloud condensation nuclei (CCN) and ice-nucleating particles (INPs) collected in and above continental and maritime boundary layers during the TRACER field project, including our efforts to develop an empirical model for estimating aerosol vertical profiles using only surface aerosol measurements when lidar observations above the surface are unavailable.