Fig. 2: Correlation between CH4 emissions and natural gas consumption.
From: Decadal decrease in Los Angeles methane emissions is much smaller than bottom-up estimates
a Time series of monthly CH4 emissions (based on CO2 emissions of ODIAC) from CLARS-FTS estimates (blue; left axis) and monthly natural gas consumption in the LA basin from residential, commercial and industrial sectors (red; right axis). The natural gas consumption time series has been shifted to the left by a half-month19. b The correlation between CH4 emissions and natural gas consumption. The correlation coefficient is 0.69. Points are color-coded by season illustrating the progressive increase in emissions from summer (red) to winter (blue). A linear regression based on orthogonal distance regression (ODR), which considers the data uncertainty, is applied. The estimated slope and intercept are (2.9 ± 0.26)% and 10.56 ± 1.80 Gg/month, respectively. c The same as (b) for monthly CH4 emissions estimated using CARB CO2 inventory. The estimated slope and intercept are (2.7 ± 0.26) % and 11.27 ± 1.81 Gg/month, respectively. The error bars represent the estimation error (1σ) of the monthly values.
