Palm, M., Melsheimer, C., No¨el, S., Heise, S., Notholt, J., Burrows, J. P., and Schrems, O.: Integrated water vapour above Ny–°Alesund, Spitsbergen: a multi–sensor intercomparison, Atmos. Chem. Phys., 10, 1–12, DOI:10.5194/acp-10-1215-2010, 2010a.