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Surface observations for monitoring urban fossil fuel CO 2 emissions: Minimum site location requirements for the Los Angeles megacity
Author(s) -
Kort Eric A.,
Angevine Wayne M.,
Duren Riley,
Miller Charles E.
Publication year - 2013
Publication title -
journal of geophysical research: atmospheres
Language(s) - English
Resource type - Journals
eISSN - 2169-8996
pISSN - 2169-897X
DOI - 10.1002/jgrd.50135
Subject(s) - megacity , environmental science , sampling (signal processing) , meteorology , limiting , flux (metallurgy) , diurnal cycle , atmospheric sciences , geography , computer science , geology , mechanical engineering , materials science , economy , filter (signal processing) , engineering , economics , computer vision , metallurgy
The contemporary global carbon cycle is dominated by perturbations from anthropogenic CO 2 emissions. One approach to identify, quantify, and monitor anthropogenic emissions is to focus on intensely emitting urban areas. In this study, we compare the ability of different CO 2 observing systems to constrain anthropogenic flux estimates in the Los Angeles megacity. We consider different observing system configurations based on existing observations and realistic near‐term extensions of the current ad hoc network. We use a high‐resolution regional model (Stochastic Time‐Inverted Lagrangian Transport‐Weather Research and Forecasting) to simulate different observations and observational network designs within and downwind of the Los Angeles (LA) basin. A Bayesian inverse method is employed to quantify the relative ability of each network to improve constraints on flux estimates. Ground‐based column CO 2 observations provide useful complementary information to surface observations due to lower sensitivity to localized dynamics, but column CO 2 observations from a single site do not appear to provide sensitivity to emissions from the entire LA megacity. Surface observations from remote, downwind sites contain weak, sporadic urban signals and are complicated by other source/sink impacts, limiting their usefulness for quantifying urban fluxes in LA. We find a network of eight optimally located in‐city surface observation sites provides the minimum sampling required for accurate monitoring of CO 2 emissions in LA, and present a recommended baseline network design. We estimate that this network can distinguish fluxes on 8 week time scales and 10 km spatial scales to within ~12 g C m –2 d –1 (~10% of average peak fossil CO 2 flux in the LA domain).