Documentation Revision Date: 2020-09-24
Dataset Version: 1.5
This dataset includes 28 data files in NetCDF (*.nc) format. Files are organized by merge type (based on sampling interval) and airborne campaign (i.e., Atom-1, 2, 3 or 4).
Wofsy, S.C., S. Afshar, H.M. Allen, E.C. Apel, E.C. Asher, B. Barletta, J. Bent, H. Bian, B.C. Biggs, D.R. Blake, N. Blake, I. Bourgeois, C.A. Brock, W.H. Brune, J.W. Budney, T.P. Bui, A. Butler, P. Campuzano-Jost, C.S. Chang, M. Chin, R. Commane, G. Correa, J.D. Crounse, P. D. Cullis, B.C. Daube, D.A. Day, J.M. Dean-Day, J.E. Dibb, J.P. DiGangi, G.S. Diskin, M. Dollner, J.W. Elkins, F. Erdesz, A.M. Fiore, C.M. Flynn, K.D. Froyd, D.W. Gesler, S.R. Hall, T.F. Hanisco, R.A. Hannun, A.J. Hills, E.J. Hintsa, A. Hoffman, R.S. Hornbrook, L.G. Huey, S. Hughes, J.L. Jimenez, B.J. Johnson, J.M. Katich, R.F. Keeling, M.J. Kim, A. Kupc, L.R. Lait, J.-F. Lamarque, J. Liu, K. McKain, R.J. Mclaughlin, S. Meinardi, D.O. Miller, S.A. Montzka, F.L. Moore, E.J. Morgan, D.M. Murphy, L.T. Murray, B.A. Nault, J.A. Neuman, P.A. Newman, J.M. Nicely, X. Pan, W. Paplawsky, J. Peischl, M.J. Prather, D.J. Price, E.A. Ray, J.M. Reeves, M. Richardson, A.W. Rollins, K.H. Rosenlof, T.B. Ryerson, E. Scheuer, G.P. Schill, J.C. Schroder, J.P. Schwarz, J.M. St.Clair, S.D. Steenrod, B.B. Stephens, S.A. Strode, C. Sweeney, D. Tanner, A.P. Teng, A.B. Thames, C.R. Thompson, K. Ullmann, P.R. Veres, N. Vieznor, N.L. Wagner, A. Watt, R. Weber, B. Weinzierl, P.O. Wennberg, C.J. Williamson, J.C. Wilson, G.M. Wolfe, C.T. Woods, and L.H. Zeng. 2018. ATom: Merged Atmospheric Chemistry, Trace Gases, and Aerosols. ORNL DAAC, Oak Ridge, Tennessee, USA. https://doi.org/10.3334/ORNLDAAC/1581
Table of Contents
- Dataset Overview
- Data Characteristics
- Application and Derivation
- Quality Assessment
- Data Acquisition, Materials, and Methods
- Data Access
- Dataset Revisions
This dataset provides information on greenhouse gases and human-produced air pollution, including atmospheric concentrations of carbon dioxide (CO2), methane (CH4), tropospheric ozone (O3), and black carbon (BC) aerosols, collected during airborne campaigns conducted by NASA's Atmospheric Tomography (ATom) mission. This dataset includes merged data from all instruments plus additional data such as numbered profiles and distance flown. Merged data have been created for seven different sampling intervals. In the case of data obtained over longer time intervals (e.g., flask data), the merge files provide (weighted) averages to match the sampling intervals. ATom deploys an extensive gas and aerosol payload on the NASA DC-8 aircraft for a systematic, global-scale sampling of the atmosphere, profiling continuously from 0.2–2 km altitude. Flights occurred in each of 4 seasons from 2016–2018. Flights originate from the Armstrong Flight Research Center in Palmdale, California, fly north to the western Arctic, south to the South Pacific, east to the Atlantic, north to Greenland, and return to California across central North America. ATom establishes a single, contiguous, global-scale dataset. This comprehensive dataset will be used to improve the representation of chemically reactive gases and short-lived climate forcers in global models of atmospheric chemistry and climate. Profiles of the reactive gases will also provide critical information for the validation of satellite data, particularly in remote areas where in situ data is lacking. Complete aircraft flight information including, but not limited to, latitude, longitude, and altitude are also provided. This data release provides results from all instruments and four ATom flight campaigns.
Project: Atmospheric Tomography Mission
The Atmospheric Tomography Mission (ATom) was a NASA Earth Venture Suborbital-2 mission. It studied the impact of human-produced air pollution on greenhouse gases and on chemically reactive gases in the atmosphere. ATom deployed an extensive gas and aerosol payload on the NASA DC-8 aircraft for systematic, global-scale sampling of the atmosphere, profiling continuously from 0.2 to 12 km altitude. Flights occurred in each of four seasons over a 4-year period.
ATom Flight Track and Navigational Data. Flight path (location and altitude) data for each of the four campaigns provided in KML and CSV format: https://doi.org/10.3334/ORNLDAAC/1613
HIAPER Pole-to-Pole Observations (HIPPO) of Carbon Cycle and Greenhouse Gases Study (2009-2011). Data available at https://www.eol.ucar.edu/field_projects/hippo
Table 1. The ATom team would like to thank the following individuals for their contributions to the success of the ATom Mission.
|G. Dutton||NOAA Earth System Research Laboratory and University of Colorado CIRES|
|B.D. Hall||NOAA Earth System Research Laboratory|
|A. McClure-Begley||NOAA Earth System Research Laboratory and University of Colorado CIRES|
|J.D. Nance||NOAA Earth System Research Laboratory and University of Colorado CIRES|
|D. Sueper||University of Colorado CIRES and Department of Chemistry|
|D.S. Thomson||University of Colorado CIRES, Department of Chemistry, and Original Code Consulting, Boulder, CO|
|NASA Headquarters and Earth Systems Science Pathfinder Office|
|B. Lefer||NASA Headquarters - Tropospheric Composition Program|
|J. Olson||NASA Langley Research Center - Earth Systems Science Pathfinder Program Office|
|NASA Earth Science Project Office|
|Q. Allison||NASA Ames Research Center and BAERI|
|S. Beddingfield||NASA Ames Research Center and BAERI|
|B. Bulger||NASA Ames Research Center and BAERI|
|D. Chirica||NASA Ames Research Center and BAERI|
|E. Czech||NASA Ames Research Center|
|K. Drdla||NASA Ames Research Center|
|D. Jordan||NASA Ames Research Center|
|E. Justice||NASA Ames Research Center and BAERI|
|E. Juvera||NASA Ames Research Center and BAERI|
|B. Luna||NASA Ames Research Center|
|S. McFadden||NASA Ames Research Center and BAERI|
|A. Padhi||NASA Ames Research Center and BAERI|
|V. Salazar||NASA Ames Research Center|
|R. Strong||NASA Ames Research Center|
|A. Thompson||NASA Ames Research Center and BAERI|
|M. Vasques||NASA Ames Research Center|
|B. Williams||NASA Ames Research Center and BAERI|
|J. Zavaleta||NASA Ames Research Center|
|NASA DC-8 Team|
|C. Bartholomew||NASA Armstrong Flight Research Center and i3|
|F. Batteas||NASA Armstrong Flight Research Center|
|M. Berry||NASA Armstrong Flight Research Center|
|M. Bereda||NASA Armstrong Flight Research Center|
|J. Borton||NASA Armstrong Flight Research Center|
|T. Dilworth||NASA Armstrong Flight Research Center|
|B. Elit||NASA Armstrong Flight Research Center and i3|
|M. Espinoza||NASA Armstrong Flight Research Center|
|D. Fedors||NASA Armstrong Flight Research Center|
|R. Garcia||NASA Armstrong Flight Research Center|
|T. Grindle||NASA Armstrong Flight Research Center|
|S. Johnson||NASA Armstrong Flight Research Center and L-3|
|W. Klein||NASA Armstrong Flight Research Center|
|S. Koertge||NASA Armstrong Flight Research Center and i3|
|D. Larson||NASA Armstrong Flight Research Center|
|L. Lohberger||NASA Armstrong Flight Research Center|
|T. Moes||NASA Armstrong Flight Research Center|
|M. Moore||NASA Armstrong Flight Research Center and L-3|
|M. Pitsch||NASA Armstrong Flight Research Center and i3|
|J. Proffitt||NASA Armstrong Flight Research Center and i3|
|R. Renfro||NASA Armstrong Flight Research Center and i3|
|W. Ringelberg||NASA Armstrong Flight Research Center|
|C. Rung||NASA Armstrong Flight Research Center|
|L. Sanchez||NASA Armstrong Flight Research Center|
|T. Sandon||NASA Armstrong Flight Research Center and i3|
|M. Scherer||NASA Armstrong Flight Research Center and L-3|
|S. Silver||NASA Armstrong Flight Research Center|
|E. Stith||NASA Armstrong Flight Research Center and BAERI|
|D. Van Gilst||NASA Armstrong Flight Research Center and BAERI|
|A. Webster||NASA Armstrong Flight Research Center and BAERI|
|B. Wehr||NASA Armstrong Flight Research Center|
|R. Williams||NASA Armstrong Flight Research Center|
|J. Wilson||NASA Armstrong Flight Research Center and Jacobs Technology, Inc.|
Spatial Coverage: Global; flights circumnavigate the globe, primarily over the oceans
Spatial Resolution: Point measurements
Temporal Coverage: Periodic flights occurred during each deployment
Table 2. ATom airborne campaign schedule.
|ATom-1||July 29 - August 23, 2016|
|ATom-2||January 26 - February 21, 2017|
|ATom-3||September 28 - October 28, 2017|
|ATom-4||April 24 - May 21, 2018|
Temporal Resolution: native resolution ranges from <1–2 seconds, depending on instrument and flight. Merge files present the data from different instruments averaged to various time bases, including 10-seconds and 1-second.
Data File Information
This dataset includes 28 data files in NetCDF (*.nc) format. Files are organized by merge type (based on sampling interval) and flight campaign (ATom-1, 2, 3 or 4). NetCDF files are structured as GeoTrajectory files, where the observations for a flight segment are connected along a one-dimensional track in space, with time increasing monotonically along the track.
File Naming Conventions
Files are organized by merge type and flight date such as MER-TYPE_aircraft_ATom-N.nc, where
MER-TYPE = merge type
aircraft = DC8
ATom-N = flight campaign, either ATom-1, 2, 3 or 4
Table 3. Merge Types
|MER-1HZ||Merge of flight data at 1-second intervals across all instruments|
|MER-MED||Data merge to MEDUSA sampling interval|
|MER-PFP||Data merge to PFP sampling interval|
|MER-SAGA-AERO||Data merge to SAGA-AERO sampling interval|
|MER-TOGA||Data merge to TOGA sampling interval, from 1-second merge file|
|MER-WAS||Data merge to WAS sampling interval|
|MER10||Merge of flight data with 10-second means|
There are over 450 individual variables measured by the 24 instruments onboard the NASA DC-8. A list of all data variables is provided in the companion file ALLNAMES.txt and in the header information of the NetCDF files themselves.
Table 4. Companion files included in this dataset.
|ALLNAMES.txt||A list of all data variables included in the merge files|
|ATom_merge.pdf||A PDF copy of this user guide|
|ATom_merging_Rcode_20170628.pdf||A script in the R language that takes data from all the instrument files and merges them to the various temporal bases provided here|
|FILELIST.ATom_MER-TYPE_Dataset.YYYYMMDD_R.txt||A list of files used generating the merge of MER-TYPE, where YYMMDD = merge date, R = version number; there are six FILELIST files|
|README.ATom_MER-TYPE_Dataset.YYYYMMDD_R.txt||Additional documentation about the merge of MER-TYPE, where YYMMDD = merge date, R = version number; there are six README files provided|
Application and Derivation
ATom builds the scientific foundation for mitigation of short-lived climate forcers, in particular, methane (CH4), tropospheric ozone (O3), and Black Carbon aerosols (BC).
ATom Science Questions
- What are chemical processes that control the short-lived climate forcing agents CH4, O3, and BC in the atmosphere? How is the chemical reactivity of the atmosphere on a global scale affected by anthropogenic emissions? How can we improve chemistry-climate modeling of these processes?
- Over large, remote regions, what are the distributions of BC and other aerosols important as short-lived climate forcers? What are the sources of new particles? How rapidly do aerosols grow to Cloud Condensation Nuclei (CCN)-active sizes? How well are these processes represented in models?
- What type of variability and spatial gradients occur over remote ocean regions for greenhouse gases (GHGs) and ozone-depleting substances (ODSs)? How do the variations among air parcels help identify anthropogenic influences on photochemical reactivity, validate satellite data for these gases, and refine knowledge of sources and sinks?
ATom delivers unique data and analysis to address the Science Mission Directorate objectives of acquiring “datasets that identify and characterize important phenomena in the changing Earth system.” and “measurements that address weaknesses in current Earth system models leading to improvement in modeling capabilities.” ATom will provide unprecedented challenges to the Chemistry-Climate Models (CCMs) used as policy tools for climate change assessments, with comprehensive data on atmospheric chemical reactivity at global scales, and will work closely with modeling teams to translate ATom data to better, more reliable CCMs. ATom provides extraordinary validation data for remote sensing.
Quality assessment procedures differ by instrument. Quality flags are provided within the data files for many of the measured parameters.
Data Acquisition, Materials, and Methods
ATom makes global-scale measurements of the chemistry of the atmosphere using the NASA DC-8 aircraft. Flights span the Pacific and Atlantic Oceans, nearly pole-to-pole, in continuous profiling mode, covering remote regions that receive long-range inputs of pollution from expanding industrial economies. The payload has proven instruments for in situ measurements of reactive and long-lived gases, diagnostic chemical tracers, and aerosol size, number, and composition, plus spectrally resolved solar radiation and meteorological parameters.
Figure 2. ATom flights continuously sampled atmospheric profiles. In this flight from Pago Pago, American Samoa to Christchurch, New Zealand, on August 8, 2016, the aircraft sampled 12 vertical profiles from about 50 to 11,000 meters above mean sea level. ATom measures more than 100 distinct chemical, aerosol, radiative, and physical parameters. Fast instrument sampling rates provide spatially resolved, simultaneous, and contiguous observational data, providing a nearly complete chemical description of each air parcel.
Combining distributions of aerosols and reactive gases with long-lived GHGs and ODSs enables disentangling of the processes that regulate atmospheric chemistry: emissions, transport, cloud processes, and chemical transformations. ATom analyzes measurements using customized modeling tools to derive daily averaged chemical rates for key atmospheric processes and to critically evaluate CCMs. ATom also differentiates between hypotheses for the formation and growth of aerosols over the remote oceans.
Table 5. Instruments on board the NASA DC-8 for ATom.
|Instrument||Full Name||Contact||Type||Measurements||Data Variables|
|AMP||In Situ Measurements of Aerosol Microphysical Properties||Charles Brock||Spectrometer (in situ)||Dry aerosol particle size distribution||NAerosol|
|AO2||NCAR Airborne Oxygen Instrument||Britt Stephens||O2, CO2||AO2|
|ATHOS||Airborne Tropospheric Hydrogen Oxides Sensor||William H. Brune||Fluorescence||OH, Naphthalene, HO2, NO||ATHOS-HOx|
|CAFS||CCD Actinic Flux Spectroradiometers||Samuel R. Hall||Spectrometer (in situ)||Actinic flux||CAFS-FLUX-N, CAFS-FLUX-Z, CAFS-JV, CAFS-JV-Z|
|CAPS Vienna||Second generation Cloud, Aerosol, and Precipitation Spectrometer – U Vienna||Bernadett Weinzierl||Spectrometer and imager (in situ)||Ambient aerosol particle, cloud droplet, and ice crystal size distributions, cloud liquid water content||Cloudindicator, NCoarseAerosol|
|CIT-CIMS||Chemical Ionization Mass Spectrometer||Paul Wennberg||CIMS||HNO3, H2O2, CH3OOH, HCN, PAA, PNA, SO2||CIT-H2O2, CIT-HCN, CIT-HNO3, CIT-MHP, CIT-PAA, CIT-PNA, CIT-SO2|
|DLH||Diode Laser Hygrometer||Glenn S. Diskin||Laser absorption||H2O||DLH-H2O|
|GT-CIMS||Chemical Ionization Mass Spectrometer||L. Greg Huey||CIMS||HNO3, SO2, HNO4, HCl, Br2, BrO, PAN||GTCIMSPANS|
|HR-AMS||CU Aircraft High-Resolution Time-of-Flight Aerosol Mass Spectrometer||Jose-Luis Jimenez||Spectrometer (in situ)||Cl, NH4, NO3, Organic aerosol, SO4||AMS, AMS-60s, AMSSD|
|ISAF||In Situ Airborne Formaldehyde||Thomas F. Hanisco||Fluorescence||CH2O||ISAF-H2CO|
|Medusa||Medusa Whole Air Sampler||Britt Stephens||Whole air sampling||O2, CO2, N2, Argon, CO2 isotopes||MEDUSA, MEDUSA-Kernel|
|MMS||Meteorological Measurement System||T. Paul Bui||Wind, turbulence, temperature, aircraft position||MMS-1HZ, MMS-20Hz|
|NOAA CIMS||Chemical Ionization Mass Spectrometer||Thomas B Ryerson||CIMS||H2O, HNO3, HCl|
|NOAA Picarro||NOAA Picarro||Kathryn McKain||Spectrometer (in situ)||
CO2, CH4, CO
See companion file (NOAA-Picarro_ATom1234_readme.pdf) for additional information about this instrument.
|NOyO3||NOAA Nitrogen Oxides and Ozone||Thomas B Ryerson||Chemiluminescence||NO, NO2, NOy, O3||NOyO3-NO, NOyO3-NO2, NOyO3-NOy, NOyO3-O3|
|PALMS||Particle Analysis By Laser Mass Spectrometry||Karl Froyd||Spectrometer (in situ)||Particle composition, aerosol||PALMS|
|PANTHER||PAN and Trace Hydrohalocarbon ExpeRiment||James W. Elkins||Gas chromatography||(CH3)2CO, PAN, H2, CH4, CO, N2O, SF6, CFCl3, CF2Cl2, Halon-1211||GCECD, GCMSD|
|PFP||Programmable Flask Package Whole Air Sampler||Steve Montzka||Whole air sampling||N2O, SF6, H2, CS2, OCS, CO2, CH4, CO, CFCs, HCFCs, HFCs, solvents, methyl halides, hydrocarbons, perfluorocarbons||PFP|
|QCLS||Quantum Cascade Laser System||Bruce Daube||Laser absorption||CO2, CO, CH4, N2O||QCLS-CH4-CO-N2O, QCLS-CO2|
|SAGA||Soluble Acidic Gases and Aerosols||Jack Dibb||Ion chromatography||Na, NH4, K, Mg, Ca+2, Cl, Br-, NO3, SO4, C2O4-2, Be-7, Pb-210, HNO3, Fine aerosol SO4, Fine aerosol NO3||SAGA-AERO, SAGA-MC|
|SP2||Single Particle Soot Photometer (NOAA)||Joshua Schwarz||Photometer||Black carbon, scattering aerosols||SP2-BC|
|TOGA||Trace Organic Gas Analyzer||Eric Apel||Gas chromatography, spectrometer (in situ)||VOCs||TOGA|
|UCATS||UAS Chromatograph for Atmospheric Trace Species||James W. Elkins||Gas chromatography, spectrometer (in situ), photometer||N2O, SF6, CH4, CO, O3||UCATS-GC, UCATS-H2O, UCATS-O3|
|WAS (UCI)||Whole Air Sampler||Donald R. Blake||Whole air sampling||NMHCs, halocarbons, alkyl nitrates, OCS, DMS, CS2||WAS|
Additional information about each instrument and the DC-8 platform is available at https://espo.nasa.gov/atom/instruments.
ATom is closely linked to satellites measuring atmospheric chemical composition: (i) ATom provides unique data for validation and algorithm development for OCO-2, GOME-2, TROPOMI, GOSAT, plus those planned for geostationary orbit (TEMPO), and the TCCON network. (ii) ATom uses satellite data to extend its airborne in-situ observations to global scale. (iii) ATom directly engages CCM groups and delivers a single, large-scale, contiguous in-situ dataset for model evaluation and improvement.
Merge File Methods
This dataset includes merged data from all instruments. A variety of merged file types have been created for each flight date. The merge files include additional data such as numbered profiles and distance flown. In the case of data obtained over longer time intervals (e.g., flask data), the merge files provide (weighted) averages of 1-second data to match the sampling intervals. The merge procedure was executed in the R language and the merge script (ATom_merging_Rcode_20170628.pdf) is provided as a companion file with this dataset. Additional details for each merge type can be found in the associated README file described in Companion Files of Section 2 above .
For more information, see the ATom website on the NASA Earth Science Project Office (ESPO) site at https://espo.nasa.gov/atom.
These data are available through the Oak Ridge National Laboratory (ORNL) Distributed Active Archive Center (DAAC).
Contact for Data Center Access Information:
- E-mail: firstname.lastname@example.org
- Telephone: +1 (865) 241-3952
Northup, E., G. Chen, K. Aikin, and C. Webster, 2017. ICARTT File Format Standards V2.0. NASA. https://cdn.earthdata.nasa.gov/conduit/upload/6158/ESDS-RFC-029v2.pdf
|1.5||2020-09-24||All previously-released data were updated to latest available versions.|
|1.4||2019-11-25||Initial release of MER-TOGA and MER-WAS data from ATom-4 campaign. All previously-released data were updated to latest available versions.|
|1.3||2019-06-14||Initial release of MER-TOGA and MER-WAS data from ATom-3 campaign. All previously-released data were updated to latest available versions.|
|1.2||2019-04-05||Initial release of partial ATom-3 & Atom-4 data. Data from Atom-1 and Atom-2 were updated to latest versions.|
|1.1||2018-08-23||Provides updated data from ATom-1 & ATom-2 with edits to author list, metadata, and user guide.|
|1.0||2018-03-28||Initial release of data from ATom-1 & ATom-2|