A53H-07
Views of Growing Methane Emissions near Oil and Natural Gas Activity: Satellite, Aircraft, and Ground
Friday, 18 December 2015: 15:10
3012 (Moscone West)
Debra E Kollonige, Earth System Science Interdisciplinary Center, COLLEGE PARK, MD, United States, Anne M Thompson, NASA Goddard Space Flight Center, Greenbelt, MD, United States, Glenn S Diskin, NASA Langley Research Center, Hampton, VA, United States, James W Hannigan, National Center for Atmospheric Research, Boulder, CO, United States and Eric Nussbaumer, NCAR, Boulder, CO, United States
Abstract:
To better understand the discrepancies between current top-down and bottom-up estimates, additional methane (CH4) measurements are necessary for regions surrounding growing oil and natural gas (ONG) development. We have evaluated satellite measurements of CH4 in US regions with ONG operations for their application as “top-down” constraints (part of the NASA Air Quality Applied Sciences Team (AQAST) project). For validation of the satellite instruments’ sensitivities to emitted gases, we focus on regions where the DISCOVER-AQ (Deriving Information on Surface Conditions from Column and Vertically Resolved Observations Relevant to Air Quality) campaign deployed ground and aircraft measurements in Maryland (2011), California and Texas (2013), and Colorado (2014). The largest CH4 signals were observed in the Greater Green River and Powder River Basins using Tropospheric Emission Spectrometer (TES) Representative Tropospheric Volume Mixing Ratio (RTVMR) measurements. A long-term comparison between a ground remote-sensing Fourier Transform Spectrometer (FTS) at Boulder and TES for 2010-2013 shows good correlation and differences ranging 2.5-5% for their yearly distribution of total column CH4. To determine any correlation between lower/mid-tropospheric CH4 (where a thermal IR sensor, such as TES, is most sensitive) and near-surface/boundary CH4 (where sources emit), we analyze the variability of DISCOVER-AQ aircraft profiles using principal component analysis and assess the correlation between near-surface (0-2 km) and mid-tropospheric (>2 km) CH4 concentrations. Using these relationships, we estimate near-surface CH4 using mid-tropospheric satellite measurements based on the partial column amounts within vertical layers with a linear regression. From this analysis, we will demonstrate whether the uncertainties of satellite-estimated near-surface CH4 are comparable to observed variability near ONG activity. These results will assist validation of satellite instrument algorithms for emissions estimates and/or provide additional information for correcting existing (TES, IASI and SCIAMACHY) and future (TROPOMI) satellite-retrieved observations.
