Observations and Modeling of Seabreeze Convection Sampled during the Tracking Aerosol Cloud IntERactions (TRACER) Experiment

The recent DOE Tracking Aerosol Cloud intERactions (TRACER) experiment focused on sampling isolated convection over Houston, TX using the DOE Atmospheric Radiation Measurement (ARM) mobile facilities (AMFs). A typical summer pattern over Houston, TX includes scattered sea breeze convection formed by clean air originating from the Gulf Coast moving inland into the polluted Houston metro area. The TRACER experiment was designed to take advantage of this natural laboratory for studying such convective cloud and aerosol properties and interactions. As part of a multi-agency experimental effort, DOE ARM deployed the AMF1 and the C-band Scanning Precipitation Radar 2 (CSAPR2) in the greater Houston area from October 2021 to October 2022 during TRACER alongside lighting flash data from the Lightning Mapping Array (LMA).
We focus this study on a case of sea-breeze generated isolated convection that formed in the Houston region in the morning of August 7, 2022. We first simulated the convection sampled on August 7 using NASA Unified WRF (NU-WRF) at 200 m horizontal grid spacing. We then apply Earth Model Column Collaboratory (EMC²) to the NU-WRF simulation, to provide simulated CSAPR2 reflectivities and hydrometeor IDs to more directly compare the model observations with CSAPR2. Both the CSAPR2 and NU-WRF simulation indicate an isolated convective cell, with the NUWRF simulated cell lasting 90 minutes longer than the observed cell with more graupel than what is present in the CSAPR2-retrieved hydrometeor IDs. The formation of graupel in the simulation could be providing more latent heat, contributing to increased buoyancy and hence a longer living storm than what was observed.