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In this study, based on an analysis of operational hourly surface and 12-hourly upper air data, the seasonal and diurnal climatological features of orographic low-level jets and associated vertical wind shear over Frobisher Bay, southern Baffin Island are discussed. These strong winds are a common phenomenon and frequently lead to hazardous flying conditions and hardship on the ground. The influence of the surrounding topography causes significant channelling of the surface wind at Iqaluit, with prevailing wind directions consequently being from the northwest and southeast. Shifts between the dominant wind directions occur with surface geostrophic winds roughly perpendicular to the valley axis, indicating the controlling influence of large-scale pressure gradients and vertical momentum transfer, in combination with local channelling effects, on the forcing of weak and strong surface winds. Following seasonal shifts in the large-scale surface pressure distribution, there is a shift in prevailing wind direction from northwest in winter to southeast in summer. The importance of the topography for the forcing of boundary-layer flows is also evident in the presence of speed maxima at the typical ridge-top level and below, associated with strong along-valley surface winds. The adjustment of the channelled boundary-layer flow to the large-scale flow conditions above the topography frequently leads to strong vertical wind shear and low-level turbulence. Distinct characteristics of weak and strong surface winds from different directions at Iqaluit are identified, including differences in vertical wind shear and the relationship of these winds to the surface geostrophic wind. RÉSUMÉ [Traduit par la rédaction] Dans cette étude, basée sur une analyse des données opérationnelles de surface horaires et aérologiques aux 12 heures, nous discutons des caractéristiques climatologiques saisonnières et journalières des courants-jets orographiques à basse altitude et du cisaillement vertical du vent qu'ils produisent dans la baie Frobisher, dans le sud de l'île de Baffin. Ces vents forts sont un phénomène courant et occasionnent fréquemment des conditions de vol dangereuses et des difficultés au sol. La topographie environnante est souvent à l'origine d'un important effet de canal sur le vent de surface à Iqaluit et c'est pourquoi les directions dominantes du vent sont le nord-ouest et le sud-est. Les sautes entre les directions dominantes du vent se produisent avec des vents géostrophiques de surface à peu près perpendiculaires à l'axe de la vallée, ce qui révèle l'influence déterminante des gradients de pression à grande échelle et du transfert vertical de quantité de mouvement, conjointement avec l'effet de canalisation local, sur le forçage des vents de surface faibles et forts. Les changements saisonniers dans la distribution de la pression à la surface à grande échelle s'accompagnent d'un changement dans la direction dominante du vent, du nord-ouest en hiver au sud-est en été. L'importance de la topographie pour le forçage de l...

The offshore wind climate in Iceland is examined based on satellite synthetic aperture radar (SAR), coastal meteorological station measurements, and results from two atmospheric model data sets, HARMONIE and NORA10. The offshore winds in Iceland are highly influenced by the rugged coastline. Lee effects, gap flow, coastal barrier jets, and atmospheric gravity waves are not only observed in SAR, but are also modeled well from HARMONIE. Offshore meteorological observations are not available, but wind speed and wind direction measurements from coastal meteorological masts are found to compare well to nearby offshore locations observed by SAR. More than 2500 SAR scenes from the Envisat ASAR wide swath mode are used for wind energy resource estimation. The wind energy potential observed from satellite SAR shows high values above 1000 Wm −2 in coastal regions in the south, east, and west, with lower values in the north. The most promising region for wind energy production is the southwestern coastal region. Index Terms-Offshore resource, polarization ratio (PR), synthetic aperture radar (SAR), wind energy, wind speed. I. INTRODUCTION D UE to the location of Iceland both close to the North Atlantic storm tracks [1] and just east of Greenland, the wind climate of Iceland is both varied and at times extremely harsh. As wind turbines in recent decades have become more robust for applications in extreme climates, the interest of wind energy utilization in Iceland has increased. Mapping the wind Manuscript

Although strong storms affect all regions of the Arctic, little research has focused on the details of their structure and evolution-particularly of the storms passing over southern Baffin Island. Such storms form in a variety of locations and often occlude before passing over the region. To study these storms, a field project was conducted at Iqaluit, Nunavut, in the eastern Canadian Arctic in the autumn of 2005. We launched rawinsondes into six storm systems and made detailed measurements that included ice crystal structure and snow accumulation. The storms had quite different histories: some produced strong winds; some produced snow, while others produced rain and freezing precipitation; and three led to record-breaking temperatures. The types of precipitation particles varied greatly, but aggregates and rimed particles dominated. When comparing the six storms, we found numerous similarities between the surface and the vertical atmospheric conditions, but there were also distinct differences.

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