Cruise Info
===========

for more info on this cruise, see our world wide web page:

     http://www.cmdl.noaa.gov/noah_home/ocean/ocean.html

Bromine Latitudinal Air/Sea Transect 1994 (BLAST 94) 
Pacific expedition in Jan/Feb 1994.

Goal:
=====
The goal of this expedition was twofold: first we intended to use a gas 
chromatograph / mass spectrometer (GC/MS) combination and tried to find out how 
reliable such an instrument can be out at sea. Secondly, the main purpose then 
was to measure methyl bromide (CH3Br) in the marine air and the surface waters 
of the East Pacific ocean and to determine wether the ocean is a source or a 
sink for this compound. Along with methyl bromide, we determined about 20 other 
compounds in both air and surface waters.

Abstract (from the SCIENCE paper listed below)
========
Surface waters along a cruise track in the East Pacific ocean were 
undersaturated in methyl bromide (CH3Br) in most areas except for coastal and 
upwelling regions, with saturation anomalies ranging from +100% in coastal 
waters to -50% in open ocean areas, representing a regionally weighted mean of 
-16 (-13 to -20) percent.

The partial lifetime of atmospheric CH3Br with respect to calculated oceanic 
degradation along this cruise track is 3.0 (2.9 to 3.6) years. The global, mean 
dry mole fraction of CH3Br in the atmosphere was 9.8±0.6 parts per trillion 
(ppt) with an interhemispheric ratio of 1.31±0.08. These data indicate that ~8 
percent (0.2 ppt) of the observed interhemispheric difference in atmospheric 
CH3Br could be attributed to an uneven global distribution of oceanic sources 
and sinks.

List of (the most important) measured compounds:
================================================
Nitrous Oxide		N2O
Sulfur hexafluoride	SF6
CFC-12			CF2Cl2
Methyl Chloride	CH3Cl
CFC-114			C2F4Cl2 symm
H-1211			CF2ClBr
Methyl Bromide		CH3Br
CFC-11			CFCl3
Methyl Iodide		CH3I
CFC-113			CCl3CF3
Methyl Chloroform	CH3CCl3
Carbon Tetrachloride	CCl4
DiBromoMethane		CH2Br2
Bromoform			CHBr3

Method:
=======
Gas chromatography / electron capture detector (GC/ECD) (N2O, SF6, CFC-12)
Gas chromatography / mass spectrometry (GC/MS) (all others)
both methods (CFC-11, CFC-113, Methyl chloroform, carbon tetrachloride).

Contact persons:
================
James H. Butler +1 303 497 6898 (tel 6290 (fax)		jbutler@cmdl.noaa.gov
Juergen M. Lobert +1 303 497 7006 (tel) 7850 (fax)	jlobert@cmdl.noaa.gov