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Observations of carbon dioxide (CO2), methane (CH4), and carbon monoxide (CO) mole fractions from the Los Angeles Megacity Carbon Project

Published by National Institute of Standards and Technology | National Institute of Standards and Technology | Catalog Last Checked: September 02, 2026 at 07:19 PM | Dataset Last Updated: April 25, 2025
Updated April 2025. Here we provide hourly observations of carbon dioxide (CO2), methane (CH4), and carbon monoxide (CO) mole fractions in dry air from tower- and rooftop-based sites in the Los Angeles Megacity Carbon Project network. Each *.tgz (tar/gzip) archive contains data files for a given site location, named by its 3-letter code. To extract *.tgz files on a unix platform, use "tar -xvzf ". Data files with in the -1-hr-CSV.tgz archives are comma delimited (CSV) 1-hour averages; data files within the _1-hr-NC.tgz archives are 1-hour averages in NetCDF format; data files within the -1-min-CSV.tgz are CSV files with 1-minute averages (there is no NetCDF version for 1-minute data). Site locations, heights, and other information are in a separate ascii (CSV) file (LAM_sites.csv), and also within each data file (for the 1-hour averages files). We encourage the use of the locations within the hourly data files, as some locations may have changed during the site lifetime and have duplicate entries in the site file. Data in this archive is for January 1 2015-January 31 2025. ASCII Readme files (1Readme_v20250425.txt and 1Readme_1minfiles_v20250425.txt) contain data details; Updates_v20250425.pdf includes additional information on updates since the previous data version. Note about calibrations: CO2 data are reported on the NOAA/WMO X2019 calibration scale. CH4 data are reported on the NOAA/WMO X2004A calibration scale; CO data, where available, are reported on the NOAA/WMO X2014 scale. Note that previous archive s of this data reported CO2 on the X2007 scale. This data is being freely distributed for research, academic and related non-commercial purposes consistent with NIST's mandate to further the science and the promulgation of appropriate standards. Current update: April 25, 2025.

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Complete Metadata
@type dcat:Dataset
accessLevel public
bureauCode 
[
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contactPoint 
{
  "fn": "Anna Karion",
  "hasEmail": "mailto:anna.karion@nist.gov"
}
description Updated April 2025. Here we provide hourly observations of carbon dioxide (CO2), methane (CH4), and carbon monoxide (CO) mole fractions in dry air from tower- and rooftop-based sites in the Los Angeles Megacity Carbon Project network. Each *.tgz (tar/gzip) archive contains data files for a given site location, named by its 3-letter code. To extract *.tgz files on a unix platform, use "tar -xvzf <filename>". Data files with in the <site>-1-hr-CSV.tgz archives are comma delimited (CSV) 1-hour averages; data files within the <site>_1-hr-NC.tgz archives are 1-hour averages in NetCDF format; data files within the <site>-1-min-CSV.tgz are CSV files with 1-minute averages (there is no NetCDF version for 1-minute data). Site locations, heights, and other information are in a separate ascii (CSV) file (LAM_sites.csv), and also within each data file (for the 1-hour averages files). We encourage the use of the locations within the hourly data files, as some locations may have changed during the site lifetime and have duplicate entries in the site file. Data in this archive is for January 1 2015-January 31 2025. ASCII Readme files (1Readme_v20250425.txt and 1Readme_1minfiles_v20250425.txt) contain data details; Updates_v20250425.pdf includes additional information on updates since the previous data version. Note about calibrations: CO2 data are reported on the NOAA/WMO X2019 calibration scale. CH4 data are reported on the NOAA/WMO X2004A calibration scale; CO data, where available, are reported on the NOAA/WMO X2014 scale. Note that previous archive s of this data reported CO2 on the X2007 scale. This data is being freely distributed for research, academic and related non-commercial purposes consistent with NIST's mandate to further the science and the promulgation of appropriate standards. Current update: April 25, 2025.
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identifier ark:/88434/mds2-3814
issued 2025-04-30
keyword 
[
  "Carbon Dioxide",
  "Emissions Inventory",
  "GHG Measurements",
  "Greenhouse Gases",
  "Urban Emissions Modeling"
]
language 
[
  "en"
]
license https://www.nist.gov/open/license
modified 2025-04-25 00:00:00
programCode 
[
  "006:047"
]
publisher 
{
  "name": "National Institute of Standards and Technology",
  "@type": "org:Organization"
}
references 
[
  "https://doi.org/10.5194/acp-17-8313-2017"
]
rights Non-commercial use only
spatial Greater Los Angeles Metropolitan Area
temporal 2015-01-01/2025-01-31
theme 
[
  "Environment:Greenhouse gas measurements"
]
title Observations of carbon dioxide (CO2), methane (CH4), and carbon monoxide (CO) mole fractions from the Los Angeles Megacity Carbon Project

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