Stratospheric water vapour in the vicinity of the Arctic polar vortex

• Main Authors: Maturilli, M., Fierli, Federico, Yushkov, V., Lukyanov, A., Khaykin, Sergey, Hauchecorne, Alain
• Other Authors: Alfred-Wegener-Institut, Helmholtz-Zentrum für Polar- und Meeresforschung (AWI), CNR Institute of Atmospheric Sciences and Climate (ISAC), Consiglio Nazionale delle Ricerche (CNR), Central Aerological Observatory (CAO), Russian Federal Service for Hydrometeorology and Environmental Monitoring (Roshydromet), Service d'aéronomie (SA), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)
• Format: Article in Journal/Newspaper
• Language: English
• Published: HAL CCSD 2006
• Subjects: [SDU.OCEAN]Sciences of the Universe [physics]/Ocean; Atmosphere; [SDU.STU]Sciences of the Universe [physics]/Earth Sciences; Arctic; Sodankylä
• Online Access: https://hal.archives-ouvertes.fr/hal-00330069; https://hal.archives-ouvertes.fr/hal-00330069/document; https://hal.archives-ouvertes.fr/hal-00330069/file/angeo-24-1511-2006.pdf

International audience The stratospheric water vapour mixing ratio inside, outside, and at the edge of the polar vortex has been accurately measured by the FLASH-B Lyman-Alpha hygrometer during the LAUTLOS campaign in Sodankylä, Finland, in January and February 2004. The retrieved H 2 O profiles reveal a detailed view on the Arctic lower stratospheric water vapour distribution, and provide a valuable dataset for the validation of model and satellite data. Analysing the measurements with the semi-lagrangian advection model MIMOSA, water vapour profiles typical for the polar vortex' interior and exterior have been identified, and laminae in the observed profiles have been correlated to filamentary structures in the potential vorticity field. Applying the validated MIMOSA transport scheme to specific humidity fields from operational ECMWF analyses, large discrepancies from the observed profiles arise. Although MIMOSA is able to reproduce weak water vapour filaments and improves the shape of the profiles compared to operational ECMWF analyses, both models reveal a dry bias of about 1 ppmv in the lower stratosphere above 400 K, accounting for a relative difference from the measurements in the order of 20%. The large dry bias in the analysis representation of stratospheric water vapour in the Arctic implies the need for future regular measurements of water vapour in the polar stratosphere to allow the validation and improvement of climate models.