Nitrous oxide emissions from the Arabian Sea: A synthesis
1Max Planck Institute for Chemistry, Mainz, Germany
2Physical Research Laboratory, Ahmedabad, India
3Plymouth Marine Laboratory, Plymouth, United Kingdom
4National Institute of Oceanography, Dona Paula, Goa, India
5University of Hamburg, Hamburg, Germany
6University of Newcastle, Newcastle upon Tyne, United Kingdom
7now at Institute for Marine Research, Kiel, Germany
8now at Frontier Research System for Global Change, Yokohama, Japan
9now at Center for Tropical Marine Ecology, Bremen, Germany
Abstract. We computed high-resolution (1º latitude x 1º longitude) seasonal and annual nitrous oxide (N2O) concentration fields for the Arabian Sea surface layer using a database containing more than 2400 values measured between December 1977 and July 1997. N2O concentrations are highest during the southwest (SW) monsoon along the southern Indian continental shelf. Annual emissions range from 0.33 to 0.70 Tg N2O and are dominated by fluxes from coastal regions during the SW and northeast monsoons. Our revised estimate for the annual N2O flux from the Arabian Sea is much more tightly constrained than the previous consensus derived using averaged in-situ data from a smaller number of studies. However, the tendency to focus on measurements in locally restricted features in combination with insufficient seasonal data coverage leads to considerable uncertainties of the concentration fields and thus in the flux estimates, especially in the coastal zones of the northern and eastern Arabian Sea. The overall mean relative error of the annual N2O emissions from the Arabian Sea was estimated to be at least 65%.
Citation: Bange, H. W., Andreae, M. O., Lal, S., Law, C. S., Naqvi, S. W. A., Patra, P. K., Rixen, T., and Upstill-Goddard, R. C.: Nitrous oxide emissions from the Arabian Sea: A synthesis, Atmos. Chem. Phys., 1, 61-71, doi:10.5194/acp-1-61-2001, 2001.