Trace Gases from the Atmospheric Lifetime Experiment/Global Atmospheric Gases Experiment/Advanced GAGE (ALE/GAGE/GAGE) from CDIAC/DB1001
Entry ID:
ALE_GAGE_AGAGE_NETWORK
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Summary
Abstract:
In the ALE/GAGE/AGAGE global network program, continuous high frequency gas chromatographic measurements of two biogenic/anthropogenic gases (methane, CH4; nitrous oxide, N2O) and eight anthropogenic gases (chlorofluorocarbons CFCl3, CF2Cl2, and CF2ClCFCl2; methyl chloroform, CH3CCl3; carbon tetrachloride, CCl4; chloroform, CHCl3; hydrofluorocarbon-134a, CH2FCF3; ... hydrofluorocarbons 141b and
142b, CH3CCl2F and CH3CClF2; methyl chloride and methyl bromide) are carried
out at 5 globally distributed sites for over 20 years. Data are currently
available for all of the species, although chloroform data are only available
for recent years. Additional important species have been added at select sites
during the course of the program. These include: hydrogen (H2), carbon monoxide
(CO), methyl chloride (CH3Cl), methyl bromide (CH3Br), HFC-134a, HFC-152a,
HCFC-141b, HCFC-142b, HCFC-22, Halons 1211 and 1301, sulfur hexafluoride (SF6),
methylene chloride (CH2C12), trichloroethylene (C2HC13), and
tetrachloroethylene (C2C14). The last 3 short-lived gases arise from solvents;
AGAGE is attempting to assess their source terms, trends, and seasonal
influences that are related to their destruction by the hydroxyl (OH) radical.
The program is divided into three parts, reflecting changes in instrumentation.
The ALE program, begun in 1978, used a Hewlett Packard HP5840 gas
chromatograph; the GAGE program, begun in 1983, uses an HP5880 gas
chromatograph. The recently initiated Advanced GAGE (AGAGE) uses a new fully
automated system designed by the Scripps Institution of Oceanography containing
custom-designed sample module and an HP5890 and Carle gas chromatographic
instruments.
The GAGE and AGAGE data were updated and revised through September 2004. The
GAGE data were re-calibrated to bring the GAGE data up to the same calibration
standards as the AGAGE data. The old HP5880 instruments used in GAGE have been
turned off and with the possible exception of Samoa, there will be no more new
GAGE data. Revisions are still possible if calibration standards are
recalculated.
Data is currently collected at monitoring sites at Cape Grim, Tasmania; Port
Matatula, American Samoa; Ragged Point, Barbados; Mace Head, Ireland; and, Cape
Trinidad, California. A site at Adrigole, Ireland was replaced by Mace Head.
The Cape Meares, Oregon site was replaced by Trinidad Head, California. During
ALE, data was collected 4 times per day and during GAGE, 12 times per day.
Data from all three experiments are posted. AGAGE data through March 2006 are
now available for all five existing sites (although monthly data for Trinidad
Head, California, USA, are only summarized through October 2004). Individual
measurements (generally made 4 times daily at each site for ALE, 12 times daily
at each site for GAGE, and more than 30 times daily at each site for AGAGE) and
monthly summary averages are provided for each site. All ALE and GAGE data have
been recalculated according to the current AGAGE calibration standards, thus
creating a unified ALE/GAGE/AGAGE data set. All ALE/GAGE/AGAGE data previously
reported based on the Scripps Institution of Oceanography (SIO)-1998
calibration scale are now recalibrated to the SIO-2005 scale; more information
about instrumentation and calibration for ALE, GAGE and AGAGE is given by Prinn
et al. (2000).
The ALE/GAGE/AGAGE data and documentation are available:
http://cdiac.ornl.gov/ndps/alegage.html
and
http://cdiac.ornl.gov/ftp/ale_gage_Agage/
The directories 'gage', 'Agage', and 'ale' contains two
subdirectories: 'complete' representing all individual measurements (4
times daily at each site for ALE and 12 times daily for each site for
GAGE and AGAGE); and 'monthly', representing monthly summary averages
of individual measurements. Data are in units of dry air mole
fractions multiplied by 10**12 for all halocarbons and dry air mole
fractions multiplied by 10**9 for nitrous oxide and methane.
Please see the 'readme' file in the 'ale', 'gage', or 'Agage'
directories for a list of references for primary standards used for
the ALE/GAGE/AGAGE datasets. 
Related URL
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Description:
Access to ALE/GAGE/AGAGE data and documentation
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Geographic Coverage
(Click for Interactive Map)
Spatial coordinates
Data Set Citation
Dataset Originator/Creator:
Bahamas Marine Mammal Survey
Dataset Title:
Bahamas Marine Mammal Survey Opportunistic Sightings
Dataset Series Name:
OBIS-SEAMAP
Dataset Release Date:
2006-06-15 12:35:37.54779-04
Dataset Release Place:
http://seamap.env.duke.edu/
Dataset Publisher:
OBIS-SEAMAP
Data Presentation Form:
vector digital data
Online Resource:
http://www.bahamaswhales.org
Parent DIF
This data set description is a member of a collection. The
collection is described in
OBIS-SEAMAP
Temporal Coverage
Start Date:
1988-12-01
Stop Date:
2005-10-10
Data Resolution
Latitude Resolution:
0.000167 Decimal degrees
Longitude Resolution:
0.000167 Decimal degrees
Horizontal Resolution Range:
1 meter - < 30 meters
Access Constraints
ACCESS CONSTRAINTS: No Constraints
DISTRIBUTION LIABILITY: Disclaimer While every effort has been made to ensure that these data are accurate and reliable within the limits of the current state of the art, NOAA cannot assume liability for any damages caused by any errors or omissions in the data, nor as a result of the failure of the data to function on a particular system. NOAA makes no warranty, expressed or implied, nor does the fact of distribution constitute such a warranty.
CUSTOM ORDER PROCESS: Contact data center for information
Use Constraints
None
Data Set Progress
COMPLETE
Distribution
Distribution Size:
2.3000
Distribution Format:
ASCII
Fees:
free online download
Personnel
Role:
TECHNICAL CONTACT
Role:
DIF AUTHOR
Phone:
(303) 497-6339
Fax:
(303) 497-6513
Email:
Carla.J.Moore at noaa.gov
Contact Address:
NOAA/NESDIS/NGDC
325 Broadway
City:
Boulder
Province or State:
CO
Postal Code:
80305-3328
Country:
USA
Creation and Review Dates
DIF Creation Date:
2010-01-22
Last DIF Revision Date:
2011-03-09
Future DIF Review Date:
2011-04-01
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