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ATom: Merged Atmospheric Chemistry, Trace Gases, and Aerosols, Version 2

Documentation Revision Date: 2021-08-27

Dataset Version: 2.0

Summary

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 products have been created for seven different aggregation intervals (1 second, 10 seconds, and 5 instrument-specific 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. 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.

ATom deployed an extensive gas and aerosol payload on the NASA DC-8 aircraft for a systematic, global-scale sampling of the atmosphere, profiling continuously from 0.2–12 km altitude. Flights occurred in each of the four seasons from 2016 to 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 established a single, contiguous, global-scale dataset. 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 on all four ATom flight campaigns.

This is Version 2 of this dataset. All previously released data were updated to the latest available versions. For details, see Section 8. Dataset Revisions.

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).

Figure 1. Generalized overview of ATom flights. During each of the four campaigns, ATom flights originated from California, flew south over the Pacific Ocean, then north to the western Arctic, southwest to New Zealand, east to Chile and the Atlantic Ocean, north to Greenland, and returned to California across North America. The aircraft continuously profiled the atmosphere from 0.2 to 12 km altitude.

Citation

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, 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.L. Wagner, A. Watt, R. Weber, B.B. Weinzierl, P.O. Wennberg, C.J. Williamson, J.C. Wilson, G.M. Wolfe, C.T. Woods, L.H. Zeng, and N. Vieznor. 2021. ATom: Merged Atmospheric Chemistry, Trace Gases, and Aerosols, Version 2. ORNL DAAC, Oak Ridge, Tennessee, USA. https://doi.org/10.3334/ORNLDAAC/1925

Table of Contents

  1. Dataset Overview
  2. Data Characteristics
  3. Application and Derivation
  4. Quality Assessment
  5. Data Acquisition, Materials, and Methods
  6. Data Access
  7. References
  8. Dataset Revisions

Dataset Overview

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 products have been created for seven different aggregation intervals (1 second, 10 seconds, and 5 instrument-specific 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. 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.

ATom deployed an extensive gas and aerosol payload on the NASA DC-8 aircraft for a systematic, global-scale sampling of the atmosphere, profiling continuously from 0.2–12 km altitude. Flights occurred in each of the four seasons from 2016 to 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 established a single, contiguous, global-scale dataset. 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 on all four ATom flight campaigns.

This is Version 2 of this dataset. All previously released data were updated to the latest available versions. For details, see Section 8. Dataset Revisions.

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.

Related Data

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

  • Version 1.5 of the current dataset. Now superseded and available only upon request.

Wofsy, S.C., and ATom Science Team. 2018. ATom: Aircraft Flight Track and Navigational Data. ORNL DAAC, Oak Ridge, Tennessee, USA. https://doi.org/10.3334/ORNLDAAC/1613

  • Flightpath (location and altitude) data for each of the four campaigns provided in KML and CSV format

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

  • HIPPO project homepage. HIPPO measured cross sections of atmospheric concentrations approximately pole-to-pole, from the surface to the tropopause, five times during different seasons over a three-year period. A comprehensive suite of atmospheric trace gases pertinent to understanding the Carbon Cycle was measured.

Acknowledgments

Table 1. The ATom team would like to thank the following individuals for their contributions to the success of the ATom Mission.

Contributor Affiliation
Science Team
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.

Data Characteristics

Spatial Coverage: Global. Flights circumnavigate the globe, primarily over the oceans

Spatial Resolution: Point measurements

Temporal Coverage: Periodic flights occurred during each campaign

Deployment Date Range
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 aggregation interval; Table 3) and flight campaign (ATom-1, 2, 3, or 4). The netCDF files are structured as GeoTrajectory, where the observations for a flight segment are connected along a one-dimensional track in space, with time increasing monotonically along the track.

The files are named according to their merge type and flight date as MER-TYPE_DC8_ATom-N.nc, where

  • MER-TYPE = merge type (Table 3)
  • ATom-N = flight campaign, either ATom-1, 2, 3, or 4

Table 3. Merge Types. Instrument acronyms are listed in Table 5.

Merge Type Averaging Interval Description
MER-1HZ 1 second Merge of measurement data at 1-second intervals across all instruments
MER-MED 25 seconds Data merged to MEDUSA sampling interval
MER-PFP Between 5–40 minutes Data merged to PFP sampling interval
MER-SAGA-AERO Between 8–25 minutes Data merged to SAGA-AERO sampling interval
MER-TOGA 120 seconds Data merged to TOGA sampling interval, from 1-second merge file
MER-WAS Between 120–200 seconds Data merged to WAS sampling interval
MER10 10 seconds Merge of measurement data at 10-second intervals across all instruments

Data File Details

There are over 450 individual variables measured by the 25 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.

Table 4. Companion files that are included in this dataset.

File Name Description
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_20210804.pdf R code used to create ATom merge ICARTT files The ORNL DAAC subsequently converted the ICARTT files to the provided netCDF format.

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

Tier 1

  • 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?

Tier 2

  • 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 CCN-active sizes? How well are these processes represented in models?
  • What type of variability and spatial gradients occurs 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?

Significance

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 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

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

Project Overview

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.

ATom flight altitude

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 campaigns. Additional information about each instrument and the DC-8 platform is available at https://espo.nasa.gov/atom/instruments.

FileName Full Name Contact Type Measurements Data Variables
AMP In Situ Measurements of Aerosol Microphysical Properties Charles Brock Spectrometer (in situ) O2, CO2 NAerosol
AO2 NCAR Airborne Oxygen Instrument Britt Stephens   OH, Naphthalene, HO2, NO AO2
ATHOS Airborne Tropospheric Hydrogen Oxides Sensor William H. Brune Fluorescence Actinic flux ATHOS-HOx
CAFS CCD Actinic Flux Spectroradiometers Samuel R. Hall Spectrometer (in situ) Ambient aerosol particle, cloud droplet, and ice crystal size distributions, cloud liquid water content 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) HNO3, H2O2, CH3OOH, HCN, PAA, PNA, SO2 Cloudindicator, NCoarseAerosol
CIT-CIMS Chemical Ionization Mass Spectrometer Paul Wennberg CIMS H2O CIT-H2O2, CIT-HCN, CIT-HNO3, CIT-MHP, CIT-PAA, CIT-PNA, CIT-SO2
DLH Diode Laser Hygrometer Glenn S. Diskin Laser absorption HNO3, SO2, HNO4, HCl, Br2, BrO, PAN DLH-H2O
GT-CIMS Chemical Ionization Mass Spectrometer L. Greg Huey CIMS Cl, NH4, NO3, Organic aerosol, SO4 GTCIMSPANS
HR-AMS CU Aircraft High-Resolution Time-of-Flight Aerosol Mass Spectrometer Jose-Luis Jimenez Spectrometer (in situ) CH2O AMS, AMS-60s, AMSSD
ISAF In Situ Airborne Formaldehyde Thomas F. Hanisco Fluorescence SO2 ISAF-H2CO
LIF-SO2 Laser Induced Florescence –Sulfur Dioxide Andrew Rollins Fluorescence O2, CO2, N2, Argon, CO2 isotopes SO2-LIF
Medusa Medusa Whole Air Sampler Britt Stephens Whole air sampling Wind, turbulence, temperature, aircraft position MEDUSA, MEDUSA-Kernel
MMS Meteorological Measurement System T. Paul Bui CIMS H2O, HNO3, HCl MMS-1HZ, MMS-20Hz
NOAA CIMS Chemical Ionization Mass Spectrometer Thomas B Ryerson Spectrometer (in situ) CO2, CH4, CO NOAA-CIMS
NOAA Picarro NOAA Picarro Kathryn McKain Chemiluminescence See companion file (NOAA-Picarro_ATom1234_readme.pdf) for additional information about this instrument. NOAA-Picarro-CO2-CH4-CO
NOyO3 NOAA Nitrogen Oxides and Ozone Thomas B Ryerson Spectrometer (in situ) NO, NO2, NOy, O3 NOyO3-NO, NOyO3-NO2, NOyO3-NOy, NOyO3-O3
PALMS Particle Analysis By Laser Mass Spectrometry Karl Froyd Gas chromatography Particle composition, aerosol PALMS
PANTHER PAN and Trace Hydrohalocarbon ExpeRiment James W. Elkins Whole air sampling (CH3)2CO, PAN, H2, CH4, CO, N2O, SF6, CFCl3, CF2Cl2, Halon-1211 GCECD, GCMSD
PFP Programmable Flask Package Whole Air Sampler Steve Montzka Laser absorption N2O, SF6, H2, CS2, OCS, CO2, CH4, CO, CFCs, HCFCs, HFCs, solvents, methyl halides, hydrocarbons, perfluorocarbons PFP
QCLS Quantum Cascade Laser System Bruce Daube Ion chromatography CO2, CO, CH4, N2O QCLS-CH4-CO-N2O, QCLS-CO2
SAGA Soluble Acidic Gases and Aerosols Jack Dibb Photometer 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 Gas chromatography, spectrometer (in situ) Black carbon, scattering aerosols SP2-BC
TOGA Trace Organic Gas Analyzer Eric Apel Gas chromatography, spectrometer (in situ), photometer VOCs TOGA
UCATS UAS Chromatograph for Atmospheric Trace Species James W. Elkins Whole air sampling N2O, SF6, CH4, CO, O3 UCATS-GC, UCATS-H2O, UCATS-O3
WAS (UCI) Whole Air Sampler Donald R. Blake Dry aerosol particle size distribution NMHCs, halocarbons, alkyl nitrates, OCS, DMS, CS2 WAS

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 a 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 ICARTT file merge procedure was performed by the ATom team. It was executed in R language and the merge script ATom_merging_Rcode_20210804.pdf)is provided as a companion file with this dataset. The merged ICARTT files were then converted to netCDF-4 format by ORNL DAAC.

For more information, see the ATom website on the NASA Earth Science Project Office (ESPO) site at https://espo.nasa.gov/atom.

Data Access

These data are available through the Oak Ridge National Laboratory (ORNL) Distributed Active Archive Center (DAAC).

ATom: Merged Atmospheric Chemistry, Trace Gases, and Aerosols, Version 2

Contact for Data Center Access Information:

References

Dataset Revisions

Version Release Date Description
2.0 2021-08-26 All previously-released data were updated to the latest available versions.
1.5 2020-09-24 All previously-released data were updated to the 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 the 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 the latest available versions.
1.2 2019-04-05 Initial release of partial ATom-3 and Atom-4 data. Data from Atom-1 and Atom-2 were updated to the latest versions.
1.1 2018-08-23 Provides updated data from ATom-1 and ATom-2 with edits to the author list, metadata, and user guide.
1.0 2018-03-28 Initial release of data from ATom-1 and ATom-2