HR: 0800h
AN: A21A-0719    [Abstracts]
TI: Odin/SMR Observations of Water Vapor and its Isotopes in the Middle Atmosphere
AU: Lautie, N
AF: Chalmers University of Technology, Radio and Space Science Department, Gothenburg, 412 96 Sweden
AU: * Urban, J
AF: Chalmers University of Technology, Radio and Space Science Department, Gothenburg, 412 96 Sweden
AB: Water vapor, a strong greenhouse gas, plays an important role for the dynamics of the middle atmosphere. It is also linked to many chemical processes like the natural destruction of ozone (through the HO$_x$ family). Improving our knowledge of the amount of water and its variability in the stratosphere and in the mesosphere is thus of primary importance. The Sub-Millimetre Radiometer (SMR) on board the Odin satellite, launched in February 2001, measures thermal emissions from the Earth's limb in the 485-580\,GHz spectral range. In particular, a band around 489\,GHz is used to study water vapor and its isotopes, on the basis of 4 observation days per month. Vertical profiles of H$_2$O-16, H$_2$O-18, and HDO are retrieved between roughly 20 and 70\,km. In addition to the interesting picture of water vapor provided in the entire middle atmosphere, the unique and original measurements of HDO and H$_2$O-18 allow to study the isotopic depletion\,/\,enrichment of water, potentially supplying information on the origin of stratospheric water vapor: transport of tropospheric air through the tropical tropopause layer (TTL) vs in-situ chemical production by methane oxydation. The presentation aims to describe the global Odin/SMR dataset of H$_2$O, HDO, and the derived quantity $\delta$D\,(H$_2$O). Particular emphasis is put on the variability seen during one year of analyzed observations. Odin is a Swedish-led satellite project funded jointly by Sweden, Canada, Finland and France.
DE: 0322 Constituent sources and sinks
DE: 0340 Middle atmosphere--composition and chemistry
DE: 0341 Middle atmosphere--constituent transport and chemistry (3334)
SC: Atmospheric Sciences [A]
MN: 2004 AGU Fall Meeting