Methane Mapping with Future Satellite Imaging Spectrometers

Alana K Ayasse,Robert O Green,David R Thompson,Riley M Duren,Philip E Dennison,Andrew K Thorpe,Markus Foote,Sarang Joshi,Dar A Roberts

doi:10.3390/rs11243054

Abstract

This study evaluates a new generation of satellite imaging spectrometers to measure point source methane emissions from anthropogenic sources. We used the Airborne Visible and Infrared Imaging Spectrometer Next Generation(AVIRIS-NG) images with known methane plumes to create two simulated satellite products. One simulation had a 30 m spatial resolution with ~200 Signal-to-Noise Ratio (SNR) in the Shortwave Infrared (SWIR) and the other had a 60 m spatial resolution with ~400 SNR in the SWIR; both products had a 7.5 nm spectral spacing. We applied a linear matched filter with a sparsity prior and an albedo correction to detect and quantify the methane emission in the original AVIRIS-NG images and in both satellite simulations. We also calculated an emission flux for all images. We found that all methane plumes were detectable in all satellite simulations. The flux calculations for the simulated satellite images correlated well with the calculated flux for the original AVIRIS-NG images. We also found that coarsening spatial resolution had the largest impact on the sensitivity of the results. These results suggest that methane detection and quantification of point sources will be possible with the next generation of satellite imaging spectrometers.

Highlights

Methane is a prominent greenhouse gas and is responsible for about 20% of all atmospheric radiative forcing [1,2]
We look at plumes from the three largest anthropogenic methane emitting sectors to understand how well a satellite system would perform in each sector
We tested the potential to use future Earth observing satellites such as Earth Surface Mineral Dust Source Investigation (EMIT) or SBG to map and measure methane plumes from the three main anthropogenic emission sectors. These particular future satellites will measure in the Shortwave Infrared (SWIR) with 7–10 nm spectral sampling, the spatial resolution will range from 30 m to 60 m pixels, and will have a Signal-to-Noise Ratio (SNR) in the SWIR between 200 and 400

Summary

Introduction

Methane is a prominent greenhouse gas and is responsible for about 20% of all atmospheric radiative forcing [1,2]. Anthropogenic sources, which make up 50–65% of all methane emissions, mostly come from the energy, waste, and agriculture sectors [2,4]. These are generally point sources, or emissions emanating from a single identifiable source like a gas storage tank or a landfill [5,6]. These sectors can contain diffuse sources, or emissions coming from a larger area, a few point sources can dominate the emissions budget. Identifying emission sources and quantifying their rates can improve regional greenhouse gas budgets and mitigation strategies [6,7]

Methods

Results

Conclusion