These data were produced by NOAA and are not subject to copyright protection in the United States. NOAA waives any potential copyright and related rights in these data worldwide through the Creative Commons Zero 1.0 Universal Public Domain Dedication (CC0 1.0)
CC0 1.0 Universal
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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:
2022-12-16
Possible contamination by room air January 2021 - May 2022, and perhaps
prior at site MBO. Large CO2 peaks with no corresponding CO peaks have been flagged.
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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://gml.noaa.gov/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
https://gml.noaa.gov/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 (optional); 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]_[optional 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 GML is lab number 1 (see https://gml.noaa.gov/ccgg/obspack/labinfo.html).
5. [optional measurement group]
Identifies the group within the NOAA GML or the Institute of Arctic and Alpine
Research (INSTAAR) at the University of Colorado Boulder that made the
measurement.
It is possible to have multiple different groups measuring some of the same
trace gas species in our discrete samples.
Measurement groups within NOAA and INSTAAR are
ccgg: NOAA Carbon Cycle Greenhouse Gases group (CCGG)
hats: NOAA Halocarbons and other Atmospheric Trace Species group (HATS)
arl: INSTAAR Atmospheric Research Laboratory (ARL)
sil: INSTAAR Stable Isotope Laboratory (SIL)
curl: INSTAAR Laboratory for Radiocarbon Preparation and Research (CURL)
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 Laboratory 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 (technically UTF-8 encoded) file is derived directly from the
netCDF file. The text file is also self-describing and can be viewed using
any ASCII or UTF-8 capable 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. Note that some non-ASCII characters (accents,
international character sets) may be present in various names and contact
information. These may require a UTF-8 capable text editor to view properly.
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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
"https://gml.noaa.gov/aftp/data/trace_gases/co2/in-situ/tower/".
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 GML 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 or a single zipped file:
https://gml.noaa.gov/aftp/data/trace_gases/co2/in-situ/tower/
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
Zipped files can be expanded using standard operating system utilities
by double clicking downloaded file.
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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 Laboratories,
Atmospheric Measurement Techniques Discussions, 6, 1, 10.5194/amtd-6-1461-2013.
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