CMS: Atmospheric CO2 and C Isotopes, Fossil Fuel Contributions, California, 2014-2015

This dataset provides measurements of atmospheric CO2 concentrations, carbon isotopes d13C and D14C, and fossil fuel CO2 (ffCO2) estimates from nine observation sites in California over three month-long campaigns in separate seasons of 2014-2015. ffCO2 was quantified based on the CO2 concentration and D14C. Simulations of ffCO2 at the sites and times of the observations were conducted with the Vulcan v2.2 fossil fuel emissions estimate for 2002 and the Weather Research and Forecasting - Stochastic Time-Inverted Lagrangian Transport (WRF-STILT) atmospheric model. The observed and simulated ffCO2 were incorporated into Bayesian inverse estimates of ffCO2 to calculate California's ffCO2 emissions during the campaign period.

There are two comma separated data (*.csv) files for this dataset.

This dataset provides measurements of atmospheric CO₂ concentrations, carbon isotopes δ¹³C and Δ¹⁴C and, fossil fuel CO₂ (ffCO₂) estimates from nine observation sites in California over three month-long campaigns in separate seasons of 2014-2015. ffCO₂ was quantified based on the CO₂ concentration and Δ¹⁴C. Simulations of ffCO₂ at the sites and times of the observations were conducted with the Vulcan v2.2 fossil fuel emissions estimate for 2002 and the Weather Research and Forecasting - Stochastic Time-Inverted Lagrangian Transport (WRF-STILT) atmospheric model. The observed and simulated ffCO₂ were incorporated into Bayesian inverse estimates of ffCO₂ to calculate California's ffCO₂ emissions during the campaign period.

Project: Carbon Monitoring System (CMS)

The NASA Carbon Monitoring System (CMS) is designed to make significant contributions in characterizing, quantifying, understanding, and predicting the evolution of global carbon sources and sinks through improved monitoring of carbon stocks and fluxes. The System will use the full range of NASA satellite observations and modeling/analysis capabilities to establish the accuracy, quantitative uncertainties, and utility of products for supporting national and international policy, regulatory, and management activities. CMS will maintain a global emphasis while providing finer scale regional information, utilizing space-based and surface-based data and will rapidly initiate generation and distribution of products both for user evaluation and to inform near-term policy development and planning.

Related Publication:
Graven, H. D., Fischer, M. L., Lueker, T., Jeong, S., Guilderson, T. P., Keeling, R., Bambha, R. P., Brophy, K., Callahan, W., Cui, X., Frankenberg, C., Gurney, K. R., LaFranchi, B., Lehman, S., Michelsen, H., Miller, J. B., Newman, S., Paplawsky, W., Parazoo, N., Sloop, C., Walker, S. J. 2018. Assessing fossil fuel CO₂ emissions in California using atmospheric observations and models. Environmental Research Letters. https://doi.org/10.1088/1748-9326/aabd43

Related Dataset:
Fischer, M.L., N.C. Parazoo, K. Brophy, X. Cui, S. Jeong, J. Liu, R. Keeling, T.E. Taylor, K.R. Gurney, T. Oda, and H. Graven. 2017. CMS: CO2 Signals Estimated for Fossil Fuel Emissions and Biosphere Flux, California. ORNL DAAC, Oak Ridge, Tennessee, USA. https://doi.org/10.3334/ORNLDAAC/1381

Acknowledgements:
This project was funded by NASA Carbon Monitoring System (NNX13AP33G and NNH13AW56I).

Spatial Coverage: California, USA

Spatial Resolution: Point locations

Temporal Coverage: 2014-05-01 through 2015-02-16

Temporal Resolution: Seasonal

Study Area (All latitudes and longitudes are given in decimal degrees):

Sites	Westernmost Longitude	Easternmost Longitude	Northernmost Latitude	Southernmost Latitude
California, USA	-124.151	-117.257	41.055	32.867

Table 1. Observation sites in California.

Site	Code	Latitude	Longitude	Sampling height (magl)
Trinidad Head	THD	41.055	-124.151	20
Sutter Buttes	STB	39.206	-121.821	10
Walnut Grove	WGC	38.265	-121.491	91
Sutro	STR	37.755	-122.452	232
Sandia-Livermore	LVR	37.674	-121.708	27
Victorville	VTR	34.609	-117.287	90
Caltech	CIT	34.137	-118.126	10
San Bernardino	SBC	34.085	-117.313	58
Scripps Inst. Ocean	SIO	32.867	-117.257	10

 

Data file information:

There  are two comma separated data (*.csv) files for this dataset. The file names and general descriptions are provided in Table 2.

 

Table 2. Data file names and general descriptions

File Name	Description
graven_ca_co2_isotopes.csv	This file contains atmospheric CO2 concentrations, Δ14C of CO2, δ13C of CO2, and fossil fuel CO2 (ffCO2) estimates from nine observation sites in California
sampling_sites_graven_ca_co2_isotopes.csv	This file contains location information for the nine observation sites.

 

The columns names, their units, and descriptions in graven_ca_co2_isotopes.csv are listed below. Missing values within the data file are reported as -9999.

Table 3. Variables in the data file.

Variable	Units/format	Description
Site	Text	One of the nine measurement sites.
Date	YYYY-MM-DD	Sampling date in UTC.
Time	hh:mm	Sampling time in UTC.
Time_zone	Text	Time zone for date and time columns.
CO2	ppm	CO2 concentration.
δ13C	per mil	Ratio of 13C to 12C in CO2, relative to VPDB
Δ14C	per mil	Ratio of 14C to C in CO2, relative to Modern and including fractionation and age corrections
beta	ppm	Correction for biospheric, non-fossil influences on Δ14C.
beta_unc	ppm	Calculated uncertainty in beta.
ffCO2	ppm	Estimated fossil fuel CO2 concentrations.
ffCO2_unc	ppm	Uncertainty in ffCO2.
prior_ffCO2	ppm	The simulated fossil fuel CO2 concentration in the prior simulation using time-varying Vulcan emissions.
post_ffCO2	ppm	The fossil fuel CO2 concentration in the posterior simulation, after the emissions have been adjusted by the standard inversion.
outlier	1 or 0	A value of 1 indicates that a measurement was determined to be an outlier, based on two criteria: (1) simulated or observed ffCO2 is greater than 5 ppm, and (2) absolute differences between simulated and observed ffCO2 are greater than the average of the simulated and observed ffCO2. Only samples that met both criteria were identified as outliers.

See Graven et al., 2018 for additional details.

See Graven et al., 2018 for more details.

CO₂ concentration and Δ¹⁴C in CO₂ was measured at nine existing observation sites within California as listed in Table 1 and shown in Figure 2. The measured CO₂ concentration and Δ¹⁴C in CO₂ was used to observe fossil-derived CO₂ (fossil fuel CO₂ or ffCO₂) emissions over California  and use the observations in a top-down calculation of California's ffCO₂ concentrations using Vulcan v2.2 and WRF-STILT atmospheric transport model. See Graven et al., 2018 for more details.
 


Figure 2. The sites in the observation network are shown as circles on the map: Trinidad Head (THD), Sutter Buttes (STB), Walnut Grove (WGC), Sutro (STR), Sandia-Livermore (LVR), Victorville (VTR), San Bernardino (SBC), Caltech (CIT) and Scripps Institution of Oceanography (SIO).

 

Fischer M. L., et al., 2017. Simulating estimation of California fossil fuel and biosphere carbon dioxide exchanges combining in-situ tower and satellite column observations. J. Geophys. Res. Atmos. 122, 3653–71. https://doi.org/10.1002/2016JD025617

Graven, H. D., Fischer, M. L., Lueker, T., Jeong, S., Guilderson, T. P., Keeling, R., Bambha, R. P., Brophy, K., Callahan, W., Cui, X., Frankenberg, C., Gurney, K. R., LaFranchi, B., Lehman, S., Michelsen, H., Miller, J. B., Newman, S., Paplawsky, W., Parazoo, N., Sloop, C., Walker, S. J. 2018. Assessing fossil fuel CO2 emissions in California using atmospheric observations and models. Environmental Research Letters. https://doi.org/10.1088/1748-9326/aabd43