High-Resolution C-band Radar Observations of Convective Cores

Understanding how water moves around in the atmosphere through convective mass flux (CMF), a critical piece of the climate system, has implications for the location and occurrence of extreme weather events. Observations of processes describing convection on scales necessary to resolve mass flux are rare and are the objective of the new NASA Earth Science Mission Investigation of Convective Updrafts (INCUS). INCUS will fly a small constellation (three) of Ka-band radars which will provide temporal resampling of tropical convection on the order of tens of seconds (30 - 120 s). Such temporal resolution observations from ground-based radars are typically unavailable and require the use of targeted (adaptive) radar observations.

Here, we leverage high resolution observations from two polarimetric C-band radars deployed in the Houston, TX area during the summer of 2022 which employed the Multi-sensor Agile Adaptive Sampling (MAAS) framework. The C-band radars were deployed as part of the in Experiment of Sea Breeze Convection, Aerosols, Precipitation and Environment (ESCAPE) and the Tracking Aerosol Convection interactions ExpeRiment (TRACER) field campaigns supported by the National Science Foundation and the Department of Energy respectively.

The two polarimetric C-band radars' data were collected using the MAAS tracking software throughout the convective lifecycle, allowing for RHI resample times of convective cores on the order of 30-120 seconds, similar to that of the planned INCUS radars. The ground-based C-band radar data are analyzed to determine the ascent rate of water mass and the characteristics of convective cells related to the CMF in a variety of isolated cells. These convective characteristics are examined in the context of their environments. As available, derived ascent rates are compared to vertical velocities measured from profilers or retrieved through dual-Doppler techniques. The updraft variability observed on these short time scales could have implications for representation of isolated convection in cloud resolving models.