Convective Cells Characterization Using Combined Observations from Scanning Dual-Polarization Doppler Radars and the GOES Satellite

Convective clouds serve as a primary mechanism for the transfer of thermal energy, moisture, and momentum through the troposphere, significantly impacting the large-scale atmospheric circulation and local environment, and affecting the probability of subsequent cloud formation. Isolated convective clouds typically last a short time (less than an hour), and as such consist of rapid evolution on many scales over their lifecycle. The Geostationary Operational Environmental Satellite R series (GOES-R) Advanced Baseline Imager offers superior spectral, spatial, and temporal resolution observations compare to its predecessors and have been extensively used to study convective initiation using VIS and IR imagery along with observations from the Next Generation Weather Radar (NEXRAD) network.

The TRacking Aerosol Convection interactions ExpeRiment (TRACER), supported by the US Department of Energy, and the Experiment of Sea Breeze Convection, Aerosols, Precipitation and Environment (ESCAPE), supported by the National Science Foundation, took place in the Houston, TX region from October 2021 through September 2022 with an intensive operational period during June – September 2022. Here, we focus on the analysis of the high-temporal-resolution observations from the two C-band polarimetric radar systems: the 2nd-generation C-band Scanning ARM Precipitation Radar (C-SAPR2) and the CSU C-band radar (CHIVO). These two systems were deployed 30 km apart from each other and were operated using a novel multiscale agile adaptive sampling strategy which allowed them to, independently or cooperatively, track convective cells throughout their lifecycle.

Here, we investigate convective cells by comparing rapid scan (10-20 sec) RHI scans from the C-SAPR2 and CHIVO radar with the concurrent GOES-R imagery after applying geolocation correction on satellite images (mainly due to parallax effect). Convective cells from radar observations were detected by setting a threshold on the cloud top height normalized Vertical Integrated Liquid (VIL), while on the geostationary images a threshold of the brightness temperature (Tb) was used. Focusing on isolated cells, during the different convective stages, a comparative study between radar integrated observables (e.g., cloud top height, height of 40 dBZ echo, normalized VIL, cells area) and their sub-minute temporal evolution (delta-t) and the GOES observables (e.g., cells area, brightness temperature (Tb) and their temporal evolution is performed. The dataset of the campaign covers the whole 2022 summer (from June 18th to September 30th, 2022). Preliminary results indicate the GOES observations correlate better with the radar observations during the early convective stage than during the mature stages. Further details of the results are discussed in the paper.