Evaluation of planetary boundary layer parameterization schemes using WoFS ensemble members and observations from TRACER

Coastal breeze circulations (bay breeze (BB), sea breeze (SB)) modulate weather conditions by advecting a maritime airmass onshore, altering air quality, and often initiating deep convection. Coastal breeze interactions with the planetary boundary layer (PBL) are not well simulated due to small-scale interactions being parameterized by numerical weather models. As part of the TRacking Aerosol Convection interactions ExpeRiment (TRACER) in Houston, Texas, PBL observations from remote sensors and uncrewed aerial systems provide a unique benchmark for evaluating model performance and investigating underlying processes. The Warn-on-Forecast System (WoFS) is a convection-allowing, 18-member ensemble designed to predict high-impact weather by combining rapidly updating data assimilation cycles with varying PBL and radiation parameterizations. The TRACER datasets are used to evaluate WoFS’s simulation of the PBL, coastal breezes, and their interactions with high vertical and temporal resolution. There is broad variability across members in the depth, arrival time, and intensity of the simulated SB case. Moreover, only a subset of members simulate the preceding BB, but none do so accurately. The radiation scheme impacts the ability to simulate a BB and onset time of the SB. The mixing scheme for PBL parameterization lends differences in depth, intensity, and evolution. Nonlocal mixing schemes allow baroclinic circulations to develop more readily, thus simulating coastal flows better, but overestimate PBL depth and temperature. The influence parameterization schemes have on meteorological biases offer potential solutions to improve simulations of coastal PBL processes.

Journal article