Gas Ex 98
Gas Exchange Experiment (1998)

The mission logo. 

Abstract

The Gas Ex 98 cruise was conducted in the North Atlantic and Northeast Pacific Oceans between May 7, 1998, and July 27, 1998.  The cruise departed from Miami, Florida, and ended in Newport, Oregon, with port stops in Lisbon, Portugal; Ponta Delgada, Azores; and Miami, Florida.  The primary focus of the cruise was a 1-month process study in which an open-ocean air-sea exchange experiment was conducted within a cold-core eddy.  The final leg was a transit run through primarily coastal waters from Miami to Newport via the Caribbean Sea and Panama Canal.

During this field campaign, we crossed oceanic regions that had been sampled on previous cruises at different times of year.  Methyl bromide supersaturations in temperate open-ocean waters of the northeastern Atlantic Ocean provided evidence for seasonality in the saturation state of this region.  In contrast, tropical waters were generally undersaturated with respect to methyl bromide in both the Atlantic and Pacific Oceans.  Data combined from this and the three BLAST cruises support a relationship between sea surface temperature and methyl bromide air-sea flux.  While this relationship can account for a large fraction of the variability in methyl bromide globally, it cannot accurately reproduce the seasonal cycle observed in temperate waters.  Results for methyl bromide from this cruise were published in 2000 (see publications list).
 
 

List of gases

 

Gas chromatograph / mass spectrometer:
HCFC-22	CHClF2
CFC-12	CCl2F2
Methyl chloride	CH3Cl
CFC-114	C2Cl2F4
Halon-1211	CBrClF2
Methyl bromide	CH3Br
CFC-11	CCl3F
Methyl iodide	CH3I
Isoprene	H2C=C(CH3)CH=CH2
CFC-113	CCl3CF3
Dichloromethane	CH2Cl2
Bromochloromethane	CH2BrCl
Chloroform	CHCl3
Methyl chloroform	CH3CCl3
Benzene	C6H6
Carbon tetrachloride	CCl4
Trichloroethylene	C2HCl3
Dibromomethane	CH2Br2
Chloroiodomethane	CH2ICl
Dibromochloromethane	CHBr2Cl
Perchloroethylene (PCE)	C2Cl4
Bromoform	CHBr3
Diiodomethane	CH2I2

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Cruise Participants:

• James H. Butler
• Daniel B. King
• Shari A. Yvon-Lewis

 

From left to right:  Dan, Jim, and Shari in Miami, prior to the cruise.

The Platform:

The NOAA Ship Ronald H. Brown in port in Miami, Florida. 
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Cruise Track:

GasEx 98 is shown in the dark purple in the North Atlantic and Northeast Pacific, out of Miami, Florida and back in to Miami before continuing on to Newport, Oregon. 

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Contacts:

• James H. Butler +1 303 497 6898 (tel) 6290 (fax) jbutler@cmdl.noaa.gov
• Daniel B. King +1 303 497 7015 (tel) 6290 (fax) dking@cmdl.noaa.gov

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Publications

Implications of methyl bromide supersaturations in the temperate North Atlantic Ocean, D.B. King, J.H. Butler, S.A. Montzka, S.A. Yvon-Lewis, and J.W. Elkins, J. Geophys. Res., 105, 19,763-19,769 (2000).

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Data & Graphs

General position and meteorological data as well as methyl bromide data are available from our public FTP site at ftp.cmdl.noaa.gov, subdir /hats/ocean/gasex_98.