Wednesday, 23 August 2023
Handout (2.8 MB)
One of the challenges in studying convective cell properties is observing the quick evolution of individual convective cells. While the operational radar data provide volumetric scans of convective precipitation and clouds, previous studies have suggested that the rapid evolution of cell lifecycles may not be captured by these conventional radar volume scan strategies, which take ~5-7 minutes. To observe convective cell evolution at high-spatiotemporal resolution, two C-band scanning polarimetric radars performed frequent updates of Range Height Indicator (RHI) and/or sector Plan Position Indicator (PPI) scans targeting individual convective cells during the Tracking Aerosol Convection Interactions ExpeRiment (TRACER) and Experiment of Sea Breeze Convection, Aerosols, Precipitation and Environment (ESCAPE) field campaigns held in Houston, TX in the summer in 2022. The cell tracking observations by the two radars were synchronized to target the same convective cell, scanning every < 2 minutes and guided by a new cell tracking framework, Multisensor Agile Adaptive Sampling (MAAS). The statistical analysis of polarimetric variables for the collected convective cells shows some diurnal variabilities. The regions of large specific differential phase (KDP), and the those of large differential reflectivity (ZDR) have higher altitudes in the afternoon (12-18 local time) compared to the morning (6-12 LT) and the evening (18-24 LT). The maximum reflectivity (Zmax) was mostly (96%) found below the melting layer and well correlated with the temporal changes of the maximum KDP and ZDR, indicating the growth of large raindrops. The positive temporal changes of Zmax included >2 dB min^-1 for both warm and cold phases. Such quick changes and correlations provide new insights into convective cell evolution but cannot be captured by the operational radar observations. We will discuss those changes accounting for observed microphysical and dynamical evolutions of the cells in varying aerosol environments.

