A First Look at Cloud Inhomogeneity and Its Effect on Lightning Optical Emission
Kelcy N. Brunner, Phillip M. Bitzer
Abstract
Abstract Optical emission observed from lightning is the result of in‐cloud scattering, lightning channel geometry, and optical energy of the source discharge. To better understand how scattering affects measured optical emission, we developed a Monte Carlo model using an inhomogeneous scattering profile from a simulated storm using two‐moment bulk microphysics in the Weather Research and Forecasting model, including the concentration and size distribution of cloud droplets and ice particles. Within the Monte Carlo model lightning discharges are simulated as point and line sources. These idealized simulations indicate that for a lightning discharge at 7 km altitude approximately 22% and 13% of light, emitted near and away (respectively) from a reflectivity core will reach cloud top in a thunderstorm. The vertical gradient of the microphysical environment impacts light reaching cloud top regardless of overall particle concentration. Increasing cloud ice modifies the gradient of the microphysical profile and modulates the profile gradient effect.