Flow-distortion corrected meteorological measurements from the Arctic century expedition in August/September 2021

I. Thurnherr1, A. Moallemi2, M. Makhotin3

1 Institute for Atmospheric and Climate Science, ETH Zurich, Switzerland
2 Extreme Environments Research Laboratory, École Polytechnique Fédérale de Lausanne, Sion, Switzerland
3 Arctic and Antarctic Research Institute, St.Petersburg, Russia


Abstract:

This data set contains meteorological measurements from the Arctic century expedition on the R/V Akademik Tryoshnikov in August and September 2021 in the Barents, Laptev and Kara Sea. A Vaisala MAWS240 meteorological station measured air temperature, relative humidity, dew point temperature and air pressure at a temporal resolution of 30sec and wind speed and wind direction at 3sec resolution. Measurements were conducted on starboard and port side. The data had been post-processed in three steps:
(1) Removal of outliers and calibration periods using interquartile
range filter (moving window)
(2) Wind flow distortion correction of relative wind direction using the approach and bias correction factors provided by Landwehr et al. 2020. For further process, the average of the corrected relative wind direction at starboard side and port side are used. For wind speeds <2m/s, no correction was applied and the time series might be biased due to flow distortion.
(3) A final time series for each variables is produced combining the starboard and port side measurements depending on relative wind direction. If the relative wind direction at a specific time step is from the 180° of the starboard side or port side, the measurement of the respective side are assign to this time step.

The data is available at the original temporal resolution of 3sec, respectively 30sec, and at 1min, 5min and 1h resolution. Before using this data, the following limitation should be noted:
(a) For wind speeds < 2m/s, no wind flow distortion correction was applied. Therefore, at low wind speeds, the time series might be biased due to flow distortion. 
(b) The wind direction has not been correction for the ship’s heading vs the ship’s direction of movement. During periods of science stations or drift, the wind direction might be biased.
(c) Relative humidity and dew point temperature are biased close to saturation and should be interpreted with caution.

These measurements can be further used for example for case studies of Arctic meteorology, air-sea interaction and fluxes, and atmospheric transport during summer 2021.

The data are provided by the Arctic Century Expedition, a joint initiative led by the Swiss Polar Institute (SPI), the Antarctic and Arctic Research Institute (AARI) and GEOMAR Helmholtz Centre for Ocean Research Kiel (GEOMAR) and funded by the Swiss Polar Foundation.

References:

Landwehr, S., Thurnherr, I., Cassar, N., Gysel-Beer, M., and Schmale, J.: Using global reanalysis data to quantify and correct airflow distortion bias in shipborne wind speed measurements, Atmos. Meas. Tech., 13, 3487–3506, https://doi.org/10.5194/amt-13-3487-2020, 2020.