Methane in surface waters of the Arabian Sea

More than 2000 measurements of atmospheric and dissolved methane (CH44) were performed in the central and northwestern Arabian Sea as part of the German JGOFS Arabian Sea Process Study during three cruises in March, May/June, and June/July 1997. Mean CH4 saturations in the surface waters of the central Arabian Sea were in the range of 103–107%. Significantly enhanced saturations were observed in the coastal upwelling area at the coast of Oman (up to 156%) and in an upwelling filament (up to 145%). The CH4 surface concentrations in the upwelling area were negatively correlated to sea surface temperatures. Area‐weighted, seasonally adjusted estimates of the sea‐air fluxes of CH4 gave annual emissions from the Arabian Sea of 11–20 Gg CH4, suggesting that previously reported very high surface CH4 concentrations might be atypical owing to the interannual variability of the Arabian Sea and that the emissions derived from them are probably overestimates.

[1]  P. Patra,et al.  Seasonal variability in distribution and fluxes of methane in the Arabian Sea , 1998 .

[2]  J. Duinker,et al.  Strong CO2 emissions from the Arabian Sea during south‐west monsoon , 1997 .

[3]  Paul J. Crutzen,et al.  An inverse modeling approach to investigate the global atmospheric methane cycle , 1997 .

[4]  T. Bates,et al.  A reevaluation of the open ocean source of methane to the atmosphere , 1996 .

[5]  M. Andreae,et al.  Methane in the Baltic and North Seas and a Reassessment of the Marine Emissions of Methane , 1994 .

[6]  Ronald D. Jones,et al.  Methane and carbon monoxide production, oxidation, and turnover times in the Caribbean Sea as influenced by the Orinoco River , 1993 .

[7]  R. Wanninkhof.  Relationship between wind speed and gas exchange over the ocean , 1992 .

[8]  P. Burkill,et al.  Methane flux to the atmosphere from the Arabian Sea , 1991, Nature.

[9]  Ronald D. Jones.  Carbon monoxide and methane distribution and consumption in the photic zone of the Sargasso Sea , 1991 .

[10]  A. Elliott,et al.  Some features of the upwelling off Oman , 1990 .

[11]  W. Seiler,et al.  Methane and hydrogen in seawater (Atlantic Ocean) , 1988 .

[12]  R. Cicerone,et al.  Biogeochemical aspects of atmospheric methane , 1988 .

[13]  B. Jähne,et al.  Measurement of the diffusion coefficients of sparingly soluble gases in water , 1987 .

[14]  Norman L. Guinasso,et al.  Equilibrium Solubilities of Methane, Carbon Monoxide, and Hydrogen in Water and Sea Water, , 1979 .

[15]  J. Garratt.  Review of Drag Coefficients over Oceans and Continents , 1977 .

[16]  V. Linnenbom,et al.  Methane concentrations in various marine environments , 1973 .

[17]  J. Lelieveld,et al.  Climate effects of atmospheric methane , 1993 .

[18]  L. Merlivat,et al.  Air-Sea Gas Exchange Rates: Introduction and Synthesis , 1986 .

[19]  P. Buat-Ménard.  The role of air-sea exchange in geochemical cycling , 1986 .

[20]  B. M. Fabuss,et al.  Appendix 2 – Properties of Sea Water , 1980 .