Case studies of the wind field around Ny-Ålesund, Svalbard, using unmanned aircraft

Abstract

The wind field in Arctic fjords is strongly influenced by glaciers, local orography and the interaction between sea and land. Ny-Ålesund, an important location for atmospheric research in the Arctic, is located in Kongsfjorden, a fjord with a complex local wind field that influences measurements in Ny-Ålesund. Using wind measurements from UAS (unmanned aircraft systems), ground measurements, radiosonde and reanalysis data, characteristic processes that determine the wind field around Ny-Ålesund are identified and analysed. UAS measurements and ground measurements show, as did previous studies, a south-east flow along Kongsfjorden, dominating the wind conditions in Ny-Ålesund. The wind measured by the UAS in a valley 1 km west of Ny-Ålesund differs from the wind measured at the ground in Ny-Ålesund. In this valley, we identify a small-scale catabatic flow from the south to south-west as the cause for this difference. Case studies show a backing (counterclockwise rotation with increasing altitude) of the wind direction close to the ground. A katabatic flow is measured near the ground, with a horizontal wind speed up to 5 m s-1. Both the larger-scale south-east flow along the fjord and the local katabatic flows lead to a highly variable wind field, so ground measurements and weather models alone give an incomplete picture. The comparison of UAS measurements, ground measurements and weather conditions analysis using a synoptic model is used to show that the effects measured in the case studies play a role in the Ny-Ålesund wind field in spring.

Tethered balloon-borne observations of thermal-infrared irradiance and cooling rate profiles in the Arctic atmospheric boundary layer

“…The fjord is oriented northwestsoutheast and is surrounded by plateaus and mountains of about 500-1000 m altitude. Their presence affects the local wind circulation and the advection of air masses (Maturilli and Kayser, 2017;Gierens et al, 2020;Schön et al, 2022).…”

Spatial distribution and variability of boundary layer aerosol particles observed in Ny-Ålesund during late spring in 2018

“…During summer, there is also a frequent north-west to south-west wind, caused by drainage flows from the Zeppelin Mountain to the fjord and low wind speed from the open sea (e.g., Beine et al, 2001;Mazzola et al, 2016). However, the wind regimes are mainly valid for the lowermost 500 m (Graßl et al, 2022), like measured at Old Pier or at the Gruvebadet observatory that is also influenced by a katabatic flow from the Broggerbreen in the west (Schön et al, 2022a). The latter is situated southwest of the village of Ny-Ålesund and south-east of the airfield at a respective distance of around 1 km (see Fig.…”

“…Processes above land in comparison with processes above open water or sea ice can be investigated by UAS operations as low altitudes. In this article, the focus is on the results of aerosol observations rather than on the technical background of the campaign that was already introduced in , and a general review of UAS campaigns in Svalbard is not in the scope of this publication and other case studies of the ALADINA period have already been subject to publications shown in , Petäjä et al (2020), Schön et al (2022a) and Xavier et al (2022).…”