Analyzing source apportioned methane in northern California during Discover-AQ-CA using airborne measurements and model simulations
This study analyzes source apportioned methane (CH4) emissions and atmospheric mixing ratios in northern California during the Discover-AQ-CA field campaign using airborne measurement data and model simulations. Source apportioned CH4 emissions from the Emissions Database for Global Atmospheric Research (EDGAR) version 4.2 were applied in the 3-D chemical transport model GEOS-Chem and analyzed using airborne measurements taken as part of the Alpha Jet Atmospheric eXperiment over the San Francisco Bay Area (SFBA) and northern San Joaquin Valley (SJV). During the time period of the Discover-AQ-CA field campaign EDGAR inventory CH4 emissions were ~5.30 Gg day –1 (Gg = 1.0 × 109 g) (equating to ~1.90 × 103 Gg yr–1) for all of California. According to EDGAR, the SFBA and northern SJV region contributes ~30% of total CH4 emissions from California. Source apportionment analysis during this study shows that CH4 mixing ratios over this area of northern California are largely influenced by global emissions from wetlands and local/global emissions from gas and oil production and distribution, waste treatment processes, and livestock management. Model simulations, using EDGAR emissions, suggest that the model under-estimates CH4 mixing ratios in northern California (average normalized mean bias (NMB) = –5.2% and linear regression slope = 0.20).more »
- NASA Ames Research Center, Moffett Field, CA (United States). Earth Sciences Div.
- NASA Ames Research Center, Moffett Field, CA (United States). Earth Sciences Div.; Carnegie Institution for Science, Stanford, CA (United States). Dept. of Global Ecology.
- Harvard Univ., Cambridge, MA (United States). Dept. of Earth and Planetary Sciences.
- Lawrence Berkeley National Lab., Berkeley, CA (United States). Environmental Energy Technologies Div.
- Publication Date:
- OSTI Identifier:
- Grant/Contract Number:
- Accepted Manuscript
- Journal Name:
- Atmospheric Environment
- Additional Journal Information:
- Journal Volume: 99; Journal Issue: C; Journal ID: ISSN 1352-2310
- Research Org:
- Lawrence Berkeley National Laboratory (LBNL), Berkeley, CA (United States)
- Sponsoring Org:
- Country of Publication:
- United States
- 54 ENVIRONMENTAL SCIENCES methane; source apportionment; emission inventory; livestock emissions