The Effects of Wind Speed, Flux Rate, and Spatial Resolution on Methane Point Source Mapping with Imaging Spectrometers

Abstract:

The Airborne Visible and Infrared Imaging Spectrometer Next Generation (AVIRIS-NG) and similar imaging spectrometers are becoming more commonly used in point source greenhouse gas emissions mapping. These instruments allow us to detect and quantify methane point sources emissions from the energy, waste management, and agriculture sectors. As methane mapping with these instruments and similar future satellite instruments becomes more prevalent, understanding those factors that influence detection is crucial. The methane emission rate and wind speed, which influence the shape and size of the plume, as well as methane concentrations within each observed methane plume can play a large role in detection sensitivity. In addition, finer spatial resolution significantly improves sensitivity given methane enhancements are distributed over smaller image pixels. We use two dimensional output from Large-Eddy Simulation (LES) plumes to understand plume dynamics at different wind speeds. These outputs are scaled to different flux rates and spatial resolutions to determine the spatial distribution of methane concentrations within plumes under different wind conditions. These simulated results allow us to characterize how wind speed, flux rate, and spatial resolution impact the methane sensitivity of AVIRIS-NG and future spaceborne imaging spectrometers.