A14F-02
Comparing observations of fossil fuel-derived CO2 in California with predictions from bottom-up inventories
Monday, 14 December 2015: 16:12
3012 (Moscone West)
Heather D Graven1, Tim Lueker2, Marc Laurenz Fischer3, Thomas P Guilderson4, Ralph F Keeling5, Kieran Brophy1, Tim Arnold6, Ray Bambha7, William Callahan8, J Elliott Campbell9, Christian Frankenberg10, Ying Hsu11, Laura T Iraci12, Seongeun Jeong13, Jooil Kim14, Brian W LaFranchi7, Scott Lehman15, Alistair Manning16, Hope A Michelsen7, John B Miller17, Sally Newman18, Nicholas Parazoo10, Christopher Sloop8, Stephen Walker5, Mary Whelan9 and Debra Wunch18, (1)Imperial College London, London, United Kingdom, (2)Scripps Institution of Oceanography, La Jolla, CA, United States, (3)Lawrence Berkeley National Laboratory, Berkeley, CA, United States, (4)Lawrence Livermore National Laboratory, Livermore, CA, United States, (5)University of California San Diego, La Jolla, CA, United States, (6)Met Office Hadley Center for Climate Change, Exeter, United Kingdom, (7)Sandia National Laboratories, Albuquerque, NM, United States, (8)Earth Networks Inc., Germantown, MD, United States, (9)University of California Merced, Merced, CA, United States, (10)NASA Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA, United States, (11)CAL/EPA (Air Resources Board), Sacramento, CA, United States, (12)NASA Ames Research Center, Moffett Field, CA, United States, (13)Lawrence Berkeley National Lab, Berkeley, CA, United States, (14)University of California San Diego, Scripps Institution of Oceanography, La Jolla, CA, United States, (15)University of Colorado at Boulder, INSTAAR, Boulder, United States, (16)UK Meteorological Office, Exeter, United Kingdom, (17)NOAA Boulder, ESRL, Boulder, CO, United States, (18)California Institute of Technology, Pasadena, CA, United States
Abstract:
The US state of California has a progressive climate change mitigation policy, AB-32, enacted in 2006 to reduce greenhouse gas emissions 15% by 2020 and then a further 80% by 2050. Bottom-up inventories indicate California’s fossil fuel CO2 emissions are currently about 100 Mt C per year, but different inventories show discrepancies of ±15% in the state-wide total, and some larger discrepancies in various sub-regions of the state. We are developing a top-down framework for investigating fossil fuel and biospheric CO2 fluxes in California using atmospheric observations and models. California has a relatively dense collaborative network of greenhouse gas observations run by several universities, government laboratories and Earth Networks. Using this collaborative network, we conducted three field campaigns in 2014-15 to sample flasks at 10 tower sites across the state. Flasks were analysed for atmospheric CO2 and CO concentrations and for stable isotopes and radiocarbon in CO2. The flask observations of radiocarbon in CO2 allow patterns of fossil fuel-derived and biospheric CO2 to be distinguished at relatively high resolution across the state. We will report initial results from the observations showing regional gradients in fossil fuel-derived CO2 and fluctuations from changing weather patterns. We will compare the observations of fossil fuel-derived CO2 to predictions from several bottom-up inventories and two atmospheric models. Linking the flask data with observations from OCO-2, TCCON, aircraft flights and ground-based in situ analyzers, we will examine the variation in total CO2 and its drivers over California. Further analysis is planned to integrate the data into an inversion framework for fossil fuel and biospheric CO2 fluxes over California.
