Weather data from MISU weather station during the Arctic Ocean 2018 expedition

Measurements of near-surface wind speed and direction, temperature, relative humidity, air pressure, shortwave and longwave downwelling radiation, and surface temperature (determined from infrared measurement) from the central Arctic Ocean in August and September 2018.

The dataset provides rare high quality meteorological observations from sea-ice regions of the Arctic Ocean. They enable analysis of meteorological conditions and provide context for other measurements and analysis associated with the expedition.

Measurements are from the MISU weather station installed on icebreaker Oden’s 7th deck at 25 m above sea level during the Arctic Ocean 2018 (AO2018, also referred to as MOCCHA-ACAS-ICE) expedition to the Arctic Ocean. Additional measurements of temperature and humidity were also made on Oden’s foremast at 20 m above sea level.

The main components of the MISU weather station (Gill 2D sonic anemometer, Rotronic aspirated TRH, Vaisala PTU pressure sensor, Eppley PIR and PSP downwelling radiation sensors) were mounted mid-ship on the 7th deck forward railing. The Heitronics KT15.IIp infrared sensor for measurement of surface temperature was mounted separately on the 7th deck, to enable measurement of the sea/ice surface to beam of the ship. During the ice-drift portion of the expedition, the infrared sensor was moved between beams following ship turns to ensure it measured from the main ice floe. An additional Rotronic aspirated TRH sensor was mounted at the top of Oden’s foremast.

Winds are measured relative to the ship. The ship acts to distort the wind speed and direction, increasingly so for winds away from bow-on. A computational fluid dynamics (CFD) model of airflow over Oden is used to correct the measured winds for wind directions within 110° of bow on. Due to the significant distortion at the site of the weather station, weather station winds should be treated with caution for wind directions more than 60° from bow on. The ship-relative winds and navigation data are also used to derive ‘true’ wind speed and direction.

Downwelling radiation sensors were subject to icing during the expedition. Ice was removed with regular cleaning. Clear-sky radiation determined from radiosonde measurements and RRTM simulations was used to provide further quality control. A flag is provided to indicate when solar radiation may be affected by shading from the ship superstructure.

The Rotronic TRH mounted on the foremast is biased high (by approximately 1 °C and 1⁠ – ⁠2 % RH), due to cable compensation effects on the analogue measurement.

Data from the system are combined into a cruise-length file. The data are time-averaged to both 1-minute and 30-minute intervals, to correspond with the micrometeorological averaging periods used for the mast sensors.

Data and Resources

Additional Info

Field Value
Principal Investigator Michael Tjernström
Data Curator John Prytherch
Version 2.0
Last Updated September 10, 2020, 18:28 (+0200)
Created September 10, 2020, 18:28 (+0200)
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