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Advances in Meteorology
Volume 2011 (2011), Article ID 486807, 14 pages
http://dx.doi.org/10.1155/2011/486807
Research Article

Characteristics of Temperature and Humidity Inversions and Low-Level Jets over Svalbard Fjords in Spring

1Meteorological Research, Finnish Meteorological Institute, 00101 Helsinki, Finland
2Department of Arctic Geophysics, The University Centre in Svalbard, 9171 Longyearbyen, Norway
3Geophysical Institute, University of Bergen, 5020 Bergen, Norway
4Department of Physics, University of Helsinki, 00014 Helsinki, Finland
5Department of Physics, University of Tartu, 50090 Tartu, Estonia
6Tartu Observatory, 61602 Tõravere, Estonia
7Department of Geography, University of Tartu, 50090 Tartu, Estonia
8Research Unit Potsdam, Alfred Wegener Institute for Polar and Marine Research, D-14473 Potsdam, Germany

Received 9 June 2011; Revised 7 December 2011; Accepted 13 December 2011

Academic Editor: Igor N. Esau

Copyright © 2011 Timo Vihma et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

Air temperature and specific humidity inversions and low-level jets were studied over two Svalbard fjords, Isfjorden and Kongsfjorden, applying three tethersonde systems. Tethersonde operation practices notably affected observations on inversion and jet properties. The inversion strength and depth were strongly affected by weather conditions at the 850 hPa level. Strong inversions were deep with a highly elevated base, and the strongest ones occurred in warm air mass. Unexpectedly, downward longwave radiation measured at the sounding site did not correlate with the inversion properties. Temperature inversions had lower base and top heights than humidity inversions, the former due to surface cooling and the latter due to adiabatic cooling with height. Most low-level jets were related to katabatic winds. Over the ice-covered Kongsfjorden, jets were lifted above a cold-air pool on the fjord; the jet core was located highest when the snow surface was coldest. At the ice-free Isfjorden, jets were located lower.