Coincident Airborne and Satellite Acquisitions of Methane Plumes

Methane super emitters are gaining importance for methane emission mitigation due to initiatives like the EPA’s Super Emitter Response Program. In addition, a variety of new methane plume-mapping sensors are coming online (e.g., Carbon Mapper/Planet Tanager, EnMAP, PRISMA, EMIT, GHGSat, MethaneSat). These sensors all have the capability to map and measure super emitters, therefore it is critical that we have robust methods to characterize the performance of individual sensors and to combine observations from multiple sensors. In this study we use coincident data from the EMIT instruments and an airborne imaging spectrometer to demonstrate the performance of EMIT and to test methods for multi-sensor observations. We use these data to constrain a Probability of Detection (POD) model for EMIT. We demonstrate that under favorable conditions the 90% probability of detection for EMIT is 700 kg/hr and the 10% probability of detection is 275 kg/hr. We also offer a new framework for how sensors with dramatically different detection limits, such as an airborne imaging spectrometer and EMIT, can be combined to accurately measure persistence and emission rates for individual sources that are observed by multiple instruments.