Talks and presentations
Assessing Urban Methane Emissions with Satellite-Derived Enhancement Ratios
Reductions in methane emissions will play an important role in meeting short-term emissions reduction goals, and feature prominently in many municipal government net-zero climate plans. Therefore, we must be able to accurately monitor emissions reductions. However, urban methane emissions are difficult to estimate, and bottom-up inventories often disagree with measurements. The use of enhancement ratios derived from satellite measurements of trace gases is a promising tool for estimating emissions and tracking emission reduction efforts. In this work, we use measurements of methane (CH4), carbon monoxide (CO), nitrogen dioxide (NO2), and carbon dioxide (CO2) from TROPOMI, OCO-2, and OCO-3 to derive CH4 enhancement ratios. We first verify our methodology with ground-based instruments and find promising agreement in the calculated enhancement ratios. We then compare our enhancement ratios measured over cities worldwide to bottom-up inventories and identify discrepancies.
Quantifying CO2 Emissions from Smaller Point Sources by Using Multiple OCO-3 Images
The ability to monitor anthropogenic CO2 emissions from space is crucial to support policy efforts to reduce emissions. NASA’s Orbiting Carbon Observatory 3 (OCO-3) has the new capability of collecting Snapshot Area Maps (SAMs), which enable effective CO2 emission estimation for large point sources. However, numerous other sources remain beyond the limit of a single SAM for effective emission quantification. In this work, we build on earlier theoretical research that explored combining XCO2 images, by overlaying multiple SAMs. The SAMs are rotated, interpolated onto a regular grid, and averaged. This process accentuates the plume and offers a higher effective spatial resolution than any individual overpass. It allows for top-down emissions estimates of smaller point sources (<7 MtCO2/yr) where they were otherwise not possible and demonstrates the advantage of the frequent revisit rate and wide-view imaging of the OCO-3 SAM mode.
Link to poster presentation
Link to conference