ERDDAP > info > ch4_flask_surface

Grid DAP Data	Sub- set	Table DAP Data	Make A Graph	W M S	Source Data Files	Title	Sum- mary	FGDC, ISO, Metadata	Back- ground Info	RSS	Institution	Dataset ID
	set	data	graph		files	Atmospheric trace gas measurements: Ch4 Flask Surface		F   I   M	background		NOAA Global Monit...	ch4_flask_surface

The Dataset's Variables and Attributes

Row Type	Variable Name	Attribute Name	Data Type	Value
attribute	NC_GLOBAL	cdm_data_type	String	TimeSeries
attribute	NC_GLOBAL	cdm_timeseries_variables	String	site_code
attribute	NC_GLOBAL	Conventions	String	COARDS, CF-1.10, ACDD-1.3
attribute	NC_GLOBAL	dataset_calibration_scale	String	CH4_X2004A
attribute	NC_GLOBAL	dataset_citation	String	Lan, X., G. Petron, K. Baugh, A.M. Crotwell, M.J. Crotwell, S. DeVogel, M. Madronich, J. Mauss, T. Mefford, E. Moglia, S. Morris, J.W. Mund, A. Searle, K.W. Thoning, S. Wolter and J. Miller (2025), Atmospheric Methane Dry Air Mole Fractions from the NOAA GML Global Greenhouse Gas Reference Network, Carbon Cycle Cooperative Global Air Sampling Network: 1983 - Present , Version: 2025-08-15, https://doi.org/10.15138/VNCZ-M766
attribute	NC_GLOBAL	dataset_comment	String	For more information about these data, please see https://gml.noaa.gov/aftp/data/trace_gases/ch4/flask/README_ch4_surface-flask_ccgg.html
attribute	NC_GLOBAL	dataset_creation_date	String	2025-08-15T13:48:06.496334
attribute	NC_GLOBAL	dataset_description	String	Atmospheric Methane Dry Air Mole Fractions from the NOAA GML Global Greenhouse Gas Reference Network, Carbon Cycle Cooperative Global Air Sampling Network: 1983 - Present
attribute	NC_GLOBAL	dataset_fair_use	String	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. To ensure that GML receives fair credit for their work please include relevant citation text in publications. We encourage users to contact the data providers, who can provide detailed information about the measurements and scientific insight. In cases where the data are central to a publication, coauthorship for data providers may be appropriate.
attribute	NC_GLOBAL	dataset_num	String	86
attribute	NC_GLOBAL	dataset_parameter	String	ch4
attribute	NC_GLOBAL	dataset_parameter_industrial_name	String	Methane
attribute	NC_GLOBAL	dataset_parameter_name	String	Methane
attribute	NC_GLOBAL	dataset_platform	String	fixed
attribute	NC_GLOBAL	dataset_project	String	surface-flask
attribute	NC_GLOBAL	dataset_provider_license	String	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).
attribute	NC_GLOBAL	dataset_reference_1_name	String	Dlugokencky, E. J., L. P. Steele, P. M. Lang and K. A. Masarie, (1994), The growth rate and distribution of atmospheric methane, Journal of Geophysical Research, 99, D8, 17, doi:10.1029/94JD01245.
attribute	NC_GLOBAL	dataset_reference_total_listed	String	1
attribute	NC_GLOBAL	dataset_selection	String	event
attribute	NC_GLOBAL	dataset_selection_tag	String	event
attribute	NC_GLOBAL	dataset_start_date	String	2006-10-27T15:50:00Z
attribute	NC_GLOBAL	dataset_stop_date	String	2010-01-13T17:42:00Z
attribute	NC_GLOBAL	dataset_usage_description	String	Please cite the product's citation when using data from this dataset. Relevant literature references for this dataset are listed below for convenience.
attribute	NC_GLOBAL	dataset_warning	String	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.
attribute	NC_GLOBAL	Easternmost_Easting	double	179.93
attribute	NC_GLOBAL	featureType	String	TimeSeries
attribute	NC_GLOBAL	geospatial_lat_max	double	82.4508
attribute	NC_GLOBAL	geospatial_lat_min	double	-89.98
attribute	NC_GLOBAL	geospatial_lat_units	String	degrees_north
attribute	NC_GLOBAL	geospatial_lon_max	double	179.93
attribute	NC_GLOBAL	geospatial_lon_min	double	-180.0
attribute	NC_GLOBAL	geospatial_lon_units	String	degrees_east
attribute	NC_GLOBAL	geospatial_vertical_max	double	4469.0
attribute	NC_GLOBAL	geospatial_vertical_min	double	2.0
attribute	NC_GLOBAL	geospatial_vertical_positive	String	up
attribute	NC_GLOBAL	geospatial_vertical_units	String	m
attribute	NC_GLOBAL	infoUrl	String	https://gml.noaa.gov/aftp/data/trace_gases/ch4/flask/surface/nc/README_ch4_surface-flask_ccgg.html
attribute	NC_GLOBAL	institution	String	NOAA Global Monitoring Laboratory
attribute	NC_GLOBAL	keywords	String	Earth Science > Atmosphere > Trace Gases > Ch4
attribute	NC_GLOBAL	keywords_vocabulary	String	GCMD Science Keywords
attribute	NC_GLOBAL	lab_1_abbr	String	NOAA
attribute	NC_GLOBAL	lab_1_address1	String	325 Broadway
attribute	NC_GLOBAL	lab_1_address2	String	NOAA R/GML-1
attribute	NC_GLOBAL	lab_1_address3	String	Boulder, CO 80305-3328
attribute	NC_GLOBAL	lab_1_country	String	United States
attribute	NC_GLOBAL	lab_1_country_flag	String	https://gml.noaa.gov/webdata/ccgg/ObsPack/images/flags/UNST0001.GIF
attribute	NC_GLOBAL	lab_1_logo	String	https://gml.noaa.gov/webdata/ccgg/ObsPack/images/logos/noaa_medium.png
attribute	NC_GLOBAL	lab_1_name	String	NOAA Global Monitoring Laboratory
attribute	NC_GLOBAL	lab_1_number	String	1
attribute	NC_GLOBAL	lab_1_ongoing_atmospheric_air_comparison	String	T
attribute	NC_GLOBAL	lab_1_parameter	String	Lab has contributed measurements for: ch4
attribute	NC_GLOBAL	lab_1_url	String	https://gml.noaa.gov/ccgg/
attribute	NC_GLOBAL	lab_total_listed	String	1
attribute	NC_GLOBAL	license	String	The data may be used and redistributed for free but is not intended for legal use, since it may contain inaccuracies. Neither the data Contributor, ERD, NOAA, nor the United States Government, nor any of their employees or contractors, makes any warranty, express or implied, including warranties of merchantability and fitness for a particular purpose, or assumes any legal liability for the accuracy, completeness, or usefulness, of this information.
attribute	NC_GLOBAL	Northernmost_Northing	double	82.4508
attribute	NC_GLOBAL	partner_1_country_flag	String	https://gml.noaa.gov/webdata/ccgg/ObsPack/images/flags/NWZE0001.GIF
attribute	NC_GLOBAL	partner_1_logo	String	https://gml.noaa.gov/webdata/ccgg/ObsPack/images/logos/niwa_medium.png
attribute	NC_GLOBAL	provider_1_address1	String	NOAA GML
attribute	NC_GLOBAL	provider_1_address2	String	325 Broadway R/GML-1
attribute	NC_GLOBAL	provider_1_address3	String	Boulder, CO 80305-3328
attribute	NC_GLOBAL	provider_1_affiliation	String	National Oceanic and Atmospheric Administration
attribute	NC_GLOBAL	provider_1_country	String	United States
attribute	NC_GLOBAL	provider_1_email	String	Xin.Lan at noaa.gov
attribute	NC_GLOBAL	provider_1_name	String	Xin Lan
attribute	NC_GLOBAL	provider_1_parameter	String	Provider has contributed measurements for: ch4
attribute	NC_GLOBAL	provider_total_listed	String	1
attribute	NC_GLOBAL	sourceUrl	String	(local files)
attribute	NC_GLOBAL	Southernmost_Northing	double	-89.98
attribute	NC_GLOBAL	standard_name_vocabulary	String	CF Standard Name Table v70
attribute	NC_GLOBAL	subsetVariables	String	site_code, dataset_parameter
attribute	NC_GLOBAL	summary	String	Atmospheric Methane Dry Air Mole Fractions from the NOAA GML Global Greenhouse Gas Reference Network, Carbon Cycle Cooperative Global Air Sampling Network: 1983 - Present
attribute	NC_GLOBAL	time_coverage_end	String	2024-12-31T19:43:00Z
attribute	NC_GLOBAL	time_coverage_start	String	1983-01-01T23:25:00Z
attribute	NC_GLOBAL	title	String	Atmospheric trace gas measurements: Ch4 Flask Surface
attribute	NC_GLOBAL	topic_category	String	environment
attribute	NC_GLOBAL	Westernmost_Easting	double	-180.0
attribute	NC_GLOBAL	wis2_topic_hierarchy	String	origin/a/wis2/noaa-gml/data/core/weather/surface-based-observations/ch4
variable	obs		short
attribute	obs	_FillValue	short	32767
attribute	obs	ioos_category	String	Unknown
attribute	obs	long_name	String	Obs
variable	time		double
attribute	time	_CoordinateAxisType	String	Time
attribute	time	actual_range	double	4.103115E8, 1.73567418E9
attribute	time	axis	String	T
attribute	time	comment	String	POSIX time. Number of seconds since January 1, 1970 in UTC. Time-averaged values are reported at the start of the averaging interval.
attribute	time	ioos_category	String	Time
attribute	time	long_name	String	Sample Time In Seconds Since January 1 1970
attribute	time	standard_name	String	time
attribute	time	time_origin	String	01-JAN-1970 00:00:00
attribute	time	units	String	seconds since 1970-01-01T00:00:00Z
variable	start_time		double
attribute	start_time	actual_range	double	4.103115E8, 1.73567418E9
attribute	start_time	comment	String	POSIX start time. Number of seconds since January 1, 1970 in UTC.
attribute	start_time	ioos_category	String	Time
attribute	start_time	long_name	String	Sample Start Time In Seconds Since January 1 1970
attribute	start_time	standard_name	String	time
attribute	start_time	time_origin	String	01-JAN-1970 00:00:00
attribute	start_time	units	String	seconds since 1970-01-01T00:00:00Z
variable	midpoint_time		double
attribute	midpoint_time	actual_range	double	4.103115E8, 1.73567418E9
attribute	midpoint_time	comment	String	POSIX midpoint time. Number of seconds since January 1, 1970 in UTC.
attribute	midpoint_time	ioos_category	String	Time
attribute	midpoint_time	long_name	String	Sample Midpoint Time In Seconds Since January 1 1970
attribute	midpoint_time	standard_name	String	time
attribute	midpoint_time	time_origin	String	01-JAN-1970 00:00:00
attribute	midpoint_time	units	String	seconds since 1970-01-01T00:00:00Z
variable	datetime		String
attribute	datetime	comment	String	Air sample date and time in UTC ISO 8601 format. Time-averaged values are reported at the start of the averaging interval.
attribute	datetime	ioos_category	String	Time
attribute	datetime	long_name	String	air_sample_date_and_time_in_UTC
variable	time_decimal		double
attribute	time_decimal	_FillValue	double	-999.999
attribute	time_decimal	actual_range	double	1983.0026731354642, 2024.9995123709775
attribute	time_decimal	comment	String	decimal year in UTC. Time-averaged values are reported at the start of the averaging interval.
attribute	time_decimal	ioos_category	String	Time
attribute	time_decimal	long_name	String	sample_decimal_year_in_UTC
variable	value		float
attribute	value	_FillValue	float	-999.999
attribute	value	actual_range	float	-999.99, 20046.76
attribute	value	colorBarMaximum	double	1.0
attribute	value	colorBarMinimum	double	0.0
attribute	value	comment	String	Mole fraction reported in units of nanomol mol-1 (10-9 mol per mol of dry air); abbreviated as ppb (parts per billion).
attribute	value	ioos_category	String	Unknown
attribute	value	long_name	String	Measured Mole Fraction Of Trace Gas In Dry Air
attribute	value	scale_comment	String	CH4_X2004A
attribute	value	units	String	nanomol mol-1
attribute	value	wmo_variable_uri	String	http://codes.wmo.int/wmdr/ObservedVariableAtmosphere/207
variable	value_unc		float
attribute	value_unc	_FillValue	float	-999.999
attribute	value_unc	actual_range	float	0.575, 4.59
attribute	value_unc	colorBarMaximum	double	10.0
attribute	value_unc	colorBarMinimum	double	-10.0
attribute	value_unc	comment	String	This is the estimated uncertainty of the reported value. See provider_comment if available.
attribute	value_unc	ioos_category	String	Quality
attribute	value_unc	long_name	String	Estimated Uncertainty In Reported Value
attribute	value_unc	units	String	nanomol mol-1
variable	latitude		float
attribute	latitude	_CoordinateAxisType	String	Lat
attribute	latitude	_FillValue	float	-999.999
attribute	latitude	actual_range	float	-89.98, 82.4508
attribute	latitude	axis	String	Y
attribute	latitude	colorBarMaximum	double	90.0
attribute	latitude	colorBarMinimum	double	-90.0
attribute	latitude	comment	String	Latitude at which air sample was collected.
attribute	latitude	ioos_category	String	Location
attribute	latitude	long_name	String	Sample Latitude In Decimal Degrees
attribute	latitude	standard_name	String	latitude
attribute	latitude	units	String	degrees_north
variable	longitude		float
attribute	longitude	_CoordinateAxisType	String	Lon
attribute	longitude	_FillValue	float	-999.999
attribute	longitude	actual_range	float	-180.0, 179.93
attribute	longitude	axis	String	X
attribute	longitude	colorBarMaximum	double	180.0
attribute	longitude	colorBarMinimum	double	-180.0
attribute	longitude	comment	String	Longitude at which air sample was collected using a range of -180 degrees to +180 degrees.
attribute	longitude	ioos_category	String	Location
attribute	longitude	long_name	String	Sample Longitude In Decimal Degrees
attribute	longitude	standard_name	String	longitude
attribute	longitude	units	String	degrees_east
variable	altitude		float
attribute	altitude	_CoordinateAxisType	String	Height
attribute	altitude	_CoordinateZisPositive	String	up
attribute	altitude	_FillValue	float	-999.999
attribute	altitude	actual_range	float	2.0, 4469.0
attribute	altitude	axis	String	Z
attribute	altitude	comment	String	Altitude (in meters above sea level). See provider_comment if available.
attribute	altitude	ioos_category	String	Location
attribute	altitude	long_name	String	Sample Altitude In Meters Above Sea Level
attribute	altitude	positive	String	up
attribute	altitude	provider_comment	String	Altitude for this dataset is the sum of surface elevation (masl) and sample intake height (magl).
attribute	altitude	standard_name	String	altitude
attribute	altitude	units	String	m
variable	elevation		float
attribute	elevation	_FillValue	float	-999.999
attribute	elevation	actual_range	float	0.0, 4464.0
attribute	elevation	comment	String	Surface elevation in meters above sea level. See provider_comment if available.
attribute	elevation	ioos_category	String	Location
attribute	elevation	long_name	String	Surface Elevation In Meters Above Sea Level
attribute	elevation	standard_name	String	altitude
attribute	elevation	units	String	m
variable	intake_height		float
attribute	intake_height	_FillValue	float	-999.999
attribute	intake_height	actual_range	float	-2.7, 2279.0
attribute	intake_height	comment	String	Sample intake height in meters above ground level (magl). See provider_comment if available.
attribute	intake_height	ioos_category	String	Location
attribute	intake_height	long_name	String	Sample Intake Height In Meters Above Ground Level
attribute	intake_height	units	String	m
variable	qcflag		String
attribute	qcflag	comment	String	This quality control flag is provided by the contributing PIs. See provider_comment if available.
attribute	qcflag	ioos_category	String	Quality
attribute	qcflag	long_name	String	Quality Control Flag
attribute	qcflag	provider_comment	String	This is the NOAA 3-character quality control flag. Column 1 is the 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 is the 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. For example, it might not have been obtained during 'background' conditions. Column 3 is the INFORMATION flag. An alphanumeric other than a period (.) in the THIRD column provides additional information about the collection or analysis of the sample. 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 determined.
variable	instrument		String
attribute	instrument	comment	String	Instrument ID used to detect atmospheric parameter. See provider_comment if available.
attribute	instrument	ioos_category	String	Identifier
attribute	instrument	long_name	String	instrument_ID_to_detect_atmospheric_parameter
variable	analysis_datetime		String
attribute	analysis_datetime	comment	String	Air sample measurement date and time in LT. See provider_comment if available.
attribute	analysis_datetime	ioos_category	String	Time
attribute	analysis_datetime	long_name	String	air_sample_measurement_date_and_time_in_LT
variable	method		String
attribute	method	comment	String	Air sample collection method. See provider_comment if available.
attribute	method	ioos_category	String	Unknown
attribute	method	long_name	String	Air Sample Collection Method
attribute	method	provider_comment	String	A single-character code is used to identify the sample collection method. The codes are: P - Sample collected using a portable, battery powered pumping unit. Two flasks are connected in series, flushed with air, and then pressurized to 1.2 - 1.5 times ambient pressure. D - Similar to P but the air passes through a condenser cooled to about 5 deg C to partially dry the sample. G - Similar to D but with a gold-plated condenser. T - Evacuated flask filled by opening an O-ring sealed stopcock. S - Flasks filled at NOAA GML observatories by sampling air from the in situ CO2 measurement air intake system. N - Before 1981, flasks filled using a hand-held aspirator bulb. After 1981, flasks filled using a pump different from those used in method P, D, or G. F - Five liter evacuated flasks filled by opening a ground glass, greased stopcock
variable	event_number		String
attribute	event_number	comment	String	Identifies each discrete air sample collected at some time and location with a unique sample event number. The event number (reported as a string) can be used to relate measurements of different trace gases and isotopes from the same sample.
attribute	event_number	ioos_category	String	Statistics
attribute	event_number	long_name	String	Unique_Air_Sample_Event_Number
variable	air_sample_container_id		String
attribute	air_sample_container_id	comment	String	ID of air sample container. See provider_comment if available.
attribute	air_sample_container_id	ioos_category	String	Identifier
attribute	air_sample_container_id	long_name	String	Air_Sample_Container_ID
variable	unique_sample_location_num		int
attribute	unique_sample_location_num	_FillValue	int	2147483647
attribute	unique_sample_location_num	actual_range	int	1019653, 104633036
attribute	unique_sample_location_num	comment	String	This variable uniquely identifies a sample location and datetime. The number assigned to each observation in this variable will be the same in all future ObsPack products including ones for other species measured in that sample.
attribute	unique_sample_location_num	ioos_category	String	Location
attribute	unique_sample_location_num	long_name	String	Unique Sample Location Num
variable	site_code		String
attribute	site_code	cf_role	String	timeseries_id
attribute	site_code	ioos_category	String	Identifier
attribute	site_code	long_name	String	Site Code
variable	site_name		String
attribute	site_name	ioos_category	String	Identifier
attribute	site_name	long_name	String	Site Name
variable	site_utc2lst		String
attribute	site_utc2lst	ioos_category	String	Other
attribute	site_utc2lst	long_name	String	Site UTC to LST Offset
variable	dataset_parameter		String
attribute	dataset_parameter	ioos_category	String	Identifier
attribute	dataset_parameter	long_name	String	Dataset Parameter

The information in the table above is also available in other file formats (.csv, .htmlTable, .itx, .json, .jsonlCSV1, .jsonlCSV, .jsonlKVP, .mat, .nc, .nccsv, .tsv, .xhtml) via a RESTful web service.