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Atmospheric CO2 Dry Air Mole Fractions from
the NOAA GMD Tower Network from 2003
National Oceanic and Atmospheric Administration (NOAA)
Earth System Research Laboratory (ESRL)
Global Monitoring Division (GMD)
Carbon Cycle Greenhouse Gases (CCGG)
Version: 2020-03-30
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CONTENTS
1. Data source and contacts
2. Use of data
2.1 Citation
3. Reciprocity
4. Warnings
5. Update notes
6. Introduction
7. DATA - General Comments
7.1 DATA - Sampling Locations
7.2 DATA - File Name Description
7.3 DATA - File Types
7.4 DATA - Content
7.5 DATA - QC Flags
8. Data retrieval
9. References
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1. DATA SOURCE AND CONTACTS
National Oceanic and Atmospheric Administration (NOAA)
Earth System Research Laboratory (ESRL)
Global Monitoring Division (GMD)
Carbon Cycle Greenhouse Gases (CCGG)
Correspondence concerning these data should be directed to:
Dr. Arlyn E. Andrews
NOAA ESRL Global Monitoring Division
325 Broadway, GMD-1
Boulder, CO 80305
U.S.A.
Email: Arlyn.Andrews@noaa.gov
Please note that some tower sites have partner providers who should be also
contacted regarding use of the data. An email list of all data providers is
below, along with information about providers for individual sites.
Email list of all data providers:
Brian.Viner@srnl.doe.gov, MLFischer@lbl.gov, arlyn.andrews@noaa.gov,
charles.e.miller@jpl.nasa.gov, colm.sweeney@noaa.gov, desai@aos.wisc.edu,
dewekker@virginia.edu, djaffe@uw.edu, john.b.miller@noaa.gov, jtlee@maine.edu
Partners for individual sites:
AMT U of ME John T. Lee jtlee@maine.edu
CRV NASA JPL Charles Miller charles.e.miller@jpl.nasa.gov
LEF U of WI Ankur Desai desai@aos.wisc.edu
MBO U of WA Dan Jaffe djaffe@uw.edu
SCT DOE/SRNL Brian Viner Brian.Viner@srnl.doe.gov
SNP U of VA Stephan de Wekker dewekker@virginia.edu
WGC DOE/LBNL Marc Fischer MLFischer@lbl.gov
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2. USE OF DATA
These data are made freely available to the public and the
scientific community in the belief that their wide dissemination
will lead to greater understanding and new scientific insights.
The availability of these data does not constitute publication
of the data. NOAA relies on the ethics and integrity of the user to
ensure that ESRL receives fair credit for their work. If the data
are obtained for potential use in a publication or presentation,
ESRL should be informed at the outset of the nature of this work.
If the ESRL data are essential to the work, or if an important
result or conclusion depends on the ESRL data, co-authorship
may be appropriate. This should be discussed at an early stage in
the work. Manuscripts using the ESRL data should be sent to ESRL
for review before they are submitted for publication so we can
ensure that the quality and limitations of the data are accurately
represented.
2.1 CITATION
Please reference these data as
Continuous measurements of CO2, CO, CH4 on tall towers starting in 1992.
A. Andrews, J. Kofler, M.E. Trudeau, P.S. Bakwin, M.L. Fischer, C. Sweeney,
A.R. Desai, B. J. Viner, M. J. Parker, D. A. Jaffe, C. E. Miller,
S. F. J. de Wekker, J. B. Miller.
NOAA Earth System Research Laboratory, Global Monitoring Division.
http://dx.doi.org/10.7289/V57W69F2
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3. RECIPROCITY
Use of these data implies an agreement to reciprocate.
Laboratories making similar measurements agree to make their
own data available to the general public and to the scientific
community in an equally complete and easily accessible form.
Modelers are encouraged to make available to the community,
upon request, their own tools used in the interpretation
of the ESRL data, namely well documented model code, transport
fields, and additional information necessary for other
scientists to repeat the work and to run modified versions.
Model availability includes collaborative support for new
users of the models.
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4. WARNINGS
Every effort is made to produce the most accurate and precise
measurements possible. However, we reserve the right to make
corrections to the data based on recalibration of standard gases
or for other reasons deemed scientifically justified.
We are not responsible for results and conclusions based on use
of these data without regard to this warning.
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5. UPDATE NOTES
+++++++++++++++++++++++++++++++
Project-specific notes:
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6. INTRODUCTION
CO2 Dry Air Mole Fraction: The CO2 abundance is given
as a mole fraction with units of parts per million (ppm).
This value corresponds to the number of CO2 molecules per
1 million molecules of dry air. Each data point represents
a 30 sec average of data collected at 0.2 Hz.
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7. DATA - GENERAL COMMENTS
7.1 DATA - SAMPLING LOCATIONS
For a summary of sampling locations, please visit
https://www.esrl.noaa.gov/gmd/ccgg/insitu/.
Note: Data for all species may not be available for all sites listed
in the table.
To view near real-time data, manipulate and compare data, and create
custom graphs, please visit
http://www.esrl.noaa.gov/gmd/dv/iadv/.
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7.2 DATA - FILE NAME DESCRIPTION
Encoded into each file name are the parameter (trace gas identifier); sampling
site; sampling project; laboratory ID number; measurement group; and optional
qualifiers that further define the file contents.
All file names use the following naming scheme:
1 2 3 4 5
[parameter]_[site]_[project]_[lab ID number]_[measurement group]_[optional
6 7
qualifiers].[file type]
1. [parameter]
Identifies the measured parameter or trace gas species.
(ex)
co2 Carbon dioxide
ch4 Methane
co2c13 d13C (co2)
merge more than one parameter
2. [site]
Identifies the sampling site code.
(ex)
brw
pocn30
car
amt
3. [project]
Identifies sampling platform and strategy.
(ex)
surface-flask
surface-pfp
surface-insitu
aircraft-pfp
aircraft-insitu
tower-insitu
4. [lab ID number]
A numeric field that identifies the sampling laboratory (1,2,3, ...).
NOAA ESRL is lab number 1 (see http://www.esrl.noaa.gov/gmd/ccgg/obspack/labinfo.html).
5. [measurement group]
Identifies the group within NOAA or INSTAAR that makes the actual measurement.
See Section 5 (UPDATE NOTES) for details.
(ex)
ccgg
hats
arl
sil
6. [optional qualifiers]
Optional qualifier(s) may indicate data subsetting or averaging.
Multiple qualifiers are delimited by an underscore (_). A more detailed
description of the file contents is included within each data file.
(ex)
event All measurement results for all collected samples (discrete (flask) data only).
month Computed monthly averages all collected samples (discrete (flask) data only).
hour_#### Computed hourly averages for the specified 4-digit year (quasi-continuous data only)
HourlyData Computed hourly averages for entire record (quasi-continuous data only)
DailyData Computed daily averages for entire record (quasi-continuous data only)
MonthlyData Computed monthly averages for entire record (quasi-continuous data only)
7. [file type]
File format (netCDF, ASCII text).
(ex)
txt ASCII text file
nc netCDF4 file
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7.3 DATA - FILE TYPE
We now provide some NOAA Global Monitoring Division measurements
in two unique file formats (netCDF and ASCII text). The Network
Common Data Form (NetCDF) is a self-describing, machine-independent
data format that supports creation, access, and sharing of array-oriented
scientific data. To learn more about netCDF and how to read netCDF
files, please visit http://www.unidata.ucar.edu.
The ASCII text file is derived directly from the netCDF file. The
text file is also self-describing and can be viewed using any text
editor. "Self-describing" means the file includes enough information
about the included data (called metadata) that no additional file is
required to understand the structure of the data and how to read and
use the data.
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7.4 DATA - CONTENT
For each tower record we provide an hourly average file.
Higher resolution data (sub-hourly) are available upon request.
All (ASCII text and netCDF) files are located in
"ftp://aftp.cmdl.noaa.gov/data/trace_gases/co2/in-situ/tower/[site]/".
Files are named as follows (see Section 7.2 for details):
co2_[site]_tower-insitu_1_ccgg_HourlyData.[file type]
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7.5 QC FLAGS
NOAA ESRL uses a 3-column quality control flag where each column
is defined as follows:
column 1 REJECTION flag. An alphanumeric other
than a period (.) in the FIRST column indicates
a sample with obvious problems during collection
or analysis. This measurement should not be interpreted.
column 2 SELECTION flag. An alphanumeric other than a
period (.) in the SECOND column indicates a sample
that is likely valid but does not meet selection
criteria determined by the goals of a particular
investigation.
column 3 INFORMATION flag. An alphanumeric other than a period (.)
in the THIRD column provides additional information
about the collection or analysis of the sample.
WARNING: A "P" in the 3rd column of the QC flag indicates
the measurement result is preliminary and has not yet been
carefully examined by the PI. The "P" flag is removed once
the quality of the measurement has been assessed.
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8. DATA RETRIEVAL
Users may transfer individual files from a directory or may choose to
transfer a single zipped file. Zipped files contain the README file
and either netCDF files or ASCII text files depending on the zipped file
name.
(ex) co2_mlo_surface-insitu_1_ASCIItext.zip
(ex) co2_mlo_surface-insitu_1_netCDF.zip
To transfer a zipped file, use the following steps from the ftp prompt:
1. ftp> binary ! set transfer mode to binary
2. ftp> get filename.zip ! transfer the file
3. ftp> bye ! leave ftp
4. $ unzip filename.zip ! uncompress your local copy
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9. REFERENCES
Andrews, A. E., J. D. Kofler, M. E. Trudeau, J. C. Williams, D. H. Neff, K. A. Masarie,
D. Y. Chao, D. R. Kitzis, P. C. Novelli, C. L. Zhao, E. J. Dlugokencky, P. M. Lang,
M. J. Crotwell, M. L. Fischer, M. J. Parker, J. T. Lee, D. D. Baumann, A. R. Desai,
C. O. Stanier, S. F. J. de Wekker, D. E. Wolfe, J. W. Munger and P. P. Tans, (2013),
CO2, CO and CH4 measurements from the NOAA Earth System Research Laboratory,
Atmospheric Measurement Techniques Discussions, 6, 1, 10.5194/amtd-6-1461-2013.
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