ACP Atmospheric Chemistry and Physics ACP 1680-7324 Copernicus GmbH Göttingen, Germany 10.5194/acp-1-61-2001 Nitrous oxide emissions from the Arabian Sea: A synthesis Bange H. W. 1 7 Andreae M. O. 1 Lal S. 2 Law C. S. 3 Naqvi S. W. A. 4 Patra P. K. 2 8 Rixen T. 5 9 Upstill-Goddard R. C. 6 Max Planck Institute for Chemistry, Mainz, Germany Physical Research Laboratory, Ahmedabad, India Plymouth Marine Laboratory, Plymouth, United Kingdom National Institute of Oceanography, Dona Paula, Goa, India University of Hamburg, Hamburg, Germany University of Newcastle, Newcastle upon Tyne, United Kingdom now at Institute for Marine Research, Kiel, Germany now at Frontier Research System for Global Change, Yokohama, Japan now at Center for Tropical Marine Ecology, Bremen, Germany 28 12 2001 1 1 61 71 This is an open-access article ditributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. This article is available from http://www.atmos-chem-phys.net/1/61/2001/acp-1-61-2001.html The full text article is available as a PDF file from http://www.atmos-chem-phys.net/1/61/2001/acp-1-61-2001.pdf

We computed high-resolution (1º latitude x&nbsp; 1º longitude) seasonal and annual nitrous oxide (N<sub>2</sub>O) concentration fields for the Arabian Sea surface layer using a database containing more than 2400 values measured between December 1977 and July 1997. N<sub>2</sub>O concentrations are highest during the southwest (SW) monsoon along the southern Indian continental shelf. Annual emissions range from 0.33 to 0.70 Tg N<sub>2</sub>O and are dominated by fluxes from coastal regions during the SW and northeast monsoons. Our revised estimate for the annual N<sub>2</sub>O 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 N<sub>2</sub>O emissions from the Arabian Sea was estimated to be at least 65%.