@article{25937,
  keywords = {California, Methane emissions, Rice, Sacramento Valley},
  author = {Jeffrey Peischl and Thomas B Ryerson and John S Holloway and Michael K Trainer and Arlyn E Andrews and Elliot L Atlas and Donald R Blake and Bruce C Daube and Edward J Dlugokencky and Marc L Fischer and Allen H Goldstein and Abhinav Guha and Thomas R Karl and Jonathan D Kofler and Edward Kosciuch and Pawel K Misztal and Anne E Perring and Ilana B Pollack and Gregory W Santoni and Joshua P Schwarz and J. J Ryan Spackman and Steven C Wofsy and David D Parrish},
  title = {Airborne observations of methane emissions from rice cultivation in the Sacramento Valley of California},
  abstract = {<p>Airborne measurements of methane (CH<sub>4</sub>) and carbon dioxide (CO<sub>2</sub>) were taken over the rice growing region of California's Sacramento Valley in the late spring of 2010 and 2011. From these and ancillary measurements, we show that CH<sub>4</sub> mixing ratios were higher in the planetary boundary layer above the Sacramento Valley during the rice growing season than they were before it, which we attribute to emissions from rice paddies. We derive daytime emission fluxes of CH<sub>4</sub> between 0.6 and 2.0% of the CO<sub>2</sub> taken up by photosynthesis on a per carbon, or mole to mole, basis. We also use a mixing model to determine an average CH<sub>4</sub>/CO<sub>2</sub> flux ratio of −0.6% for one day early in the growing season of 2010. We conclude the CH<sub>4</sub>/CO<sub>2</sub> flux ratio estimates from a single rice field in a previous study are representative of rice fields in the Sacramento Valley. If generally true, the California Air Resources Board (CARB) greenhouse gas inventory emission rate of 2.7 × 10<sup>10</sup> g CH<sub>4</sub>/yr is approximately three times lower than the range of probable CH<sub>4</sub> emissions (7.8–9.3 × 10<sup>10</sup> g CH<sub>4</sub>/yr) from rice cultivation derived in this study. We attribute this difference to decreased burning of the residual rice crop since 1991, which leads to an increase in CH<sub>4</sub> emissions from rice paddies in succeeding years, but which is not accounted for in the CARB inventory.</p>},
  year = {2012},
  journal = {Journal of Geophysical Research: Atmospheres},
  volume = {117},
  month = {12/2012},
  doi = {10.1029/2012JD017994},
}