Insights Into Wind Profile Characteristics in the Arctic Marine Boundary Layer

• Main Author: Gausa, Charlotte Sophie
• Format: Bachelor Thesis
• Language: English
• Published: Uppsala universitet, Luft-, vatten- och landskapslära 2024
• Subjects: Arctic; wind profile power law; MOST; boundary layer; low level jets; sea ice; vindprofil; Arktis; gränsskikt; vindenergi; låghöjdsvindar; havsis; Meteorology and Atmospheric Sciences; Meteorologi och atmosfärforskning; Svalbard; Bergen; Arktis*; Climate change; Sea ice; University Centre in Svalbard
• Online Access: http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-521327

The atmospheric boundary layer in the Arctic is essential for the understanding of climate change and improving regional weather prediction. The aim of this study is to investigate to which degree wind speed profiles retrieved in the Arctic agree with well known wind profile concepts and understand which local impact factors influence the wind speed profile. As part of the Nansen Legacy project, scientists from the University Centre in Svalbard and the University of Bergen installed two wind lidars onboard the research vessel “Kronprins Haakon” during the “Winter Process Cruise” in February 2021. Wind speed profiles were collected over a period of two weeks. They were manually classified into three categories based on their shape. The ideally shaped profiles were fitted against the wind profile power law to identify the exponent, α, for use in the Arctic marine boundary layer. α was found to be 4-5 times smaller than the conventionally applied α = 1/7 for profiles retrieved over open water, which was associated with unstable atmospheric conditions. Additionally, α was found to be considerably larger than 1/7 when sea ice was present, which was associated with stable conditions. A dependency on wind speed was also found. These results underline the importance of adjusting the exponent in order to ac- curately model the wind speed in the Arctic marine boundary layer. The results might be important for optimizing potential wind energy production, which is of great interest with the increasing human activ- ity in the Arctic. Reversed profiles (wind speed maxima closest to the surface) were mainly measured over open ocean and during low wind speeds and were speculated to be related to swell conditions. Pro- files containing a maxima in low levels were primarily measured during stable atmospheric conditions when sea ice was present. Future research in Arctic conditions would benefit from extending wind speed measurements to even lower levels and including stability measurements for an even deeper analysis.