Atmospheric Chemistry and Physics www.atmos-chem-phys.net 1680-7316 1680-7324 7 10 2007 10.5194/acp-7-2721-2007 http://www.atmos-chem-phys.net/7/2721/2007/ http://www.atmos-chem-phys.net/7/2721/2007/acp-7-2721-2007.html http://www.atmos-chem-phys.net/7/2721/2007/acp-7-2721-2007.pdf 2721 2732 2007-05-24 Humidity observations in the Arctic troposphere over Ny-Ålesund, Svalbard based on 15 years of radiosonde data R. Treffeisen renate.treffeisen@awi.de R. Krejci J. Ström A. C. Engvall A. Herber L. Thomason Alfred Wegener Institute for Polar and Marine Research, Telegrafenberg A45, 14473 Potsdam, Germany Department of Meteorology (MISU), Stockholm University, S 106 91 Stockholm, Sweden ITM – Department of Applied Environmental Science, Stockholm University, S 106 91 Stockholm, Sweden Alfred Wegner Institute for Polar and Marine Research, Am Handelshafen 12, 27570 Bremerhaven, Germany NASA Langley Research Center Hampton, VA 23681-2199, USA Water vapour is an important component in the radiative balance of the polar atmosphere. We present a study covering fifteen years of data of tropospheric humidity profiles measured with standard radiosondes at Ny-Ålesund (78°55' N 11°52' E) during the period from 1991 to 2006. It is well-known that relative humidity measurements are less reliable at low temperatures when measured with standard radiosondes. 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