Winter atmospheric boundary layer observations over sea ice in the coastal zone of the Bothnian Bay (Baltic Sea)

• Main Authors: Wenta, Marta, Brus, David, Doulgeris, Konstantinos-Matthaios, Vakkari, Ville, Herman, Agnieszka
• Format: Dataset
• Language: English
• Published: PANGAEA 2020
• Subjects: atmospheric boundary layer; Sea ice; sea ice-atmosphere interactions; UAV; unmanned aerial vehicle; Marjaniemi
• Online Access: https://doi.pangaea.de/10.1594/PANGAEA.918823; https://doi.org/10.1594/PANGAEA.918823

Presence of sea ice in the Bay of Bothnia affects the intensity of moisture and heat exchange between the atmosphere and the sea, and the radiation budget in the region. Depending on the sea ice extent it affects weather both locally and globally. The goal of Hailuoto Atmospheric Observations over Sea Ice (HAOS) campaign was to collect measurements of atmospheric boundary layer properties over the sea ice in the coastal zone west of the Hailuoto island (north-eastern Bay of Bothnia) and to increase our understanding of the processes at the interface of sea ice and air. The observations took place between 27 of February and 2 of March 2020 and included 27 fixed-wing unmanned aerial vehicle (UAV) flights at the heights of 25, 50, 75 and 100 m over the survey area of 1.5 km2, along with 4 photogrammetry missions over the sea ice below the fixed wing UAV path. The atmospheric properties measured during the flights were temperature, relative humidity and air pressure while the aerial photography was used to generate orthomosaic maps. The campaign also involved continuous observations with a ground based weather station, a 3D anemometer, and a Halo Doppler Lidar installed on the shore, at the pier of the Hailuoto Marjaniemi harbour. Data collected by two meteorological sensors installed on the fixed wing UAV include, apart from meteorological conditions: date,time, latitude, longitude, UTM coordinates, altitude. The part of the data collected outside of the prescribed trajectories (i.e. directly after take-off/before landing) has been removed during preprocessing and the altitude has been calculated using a hypsometric equation. The orthomosaic maps are provided as GeoTiff, Google Maps tiles and KML files in WGS84 (EGM 96 Geoid) Coordinate System. Weather station measurements include (logged as 1-minute averages): date and time, minimum wind direction (deg), averaged wind direction (deg), maximum wind direction (deg), minimum wind speed (m.s-1), averaged wind speed (m.s-1), maximum wind speed (m.s-1), temperature (C), ...