Wind, temperature, relative humidity, surface temperature and radiation from expedition ARTofMELT, Arctic Ocean, 2023 — raw data

Sonja Murto, Michael Tjernström, Michail Karalis, John Prytherch

A weather station was deployed on the 7th top deck of the Swedish icebreaker Oden during the ARTofMELT (Atmospheric Rivers and the Onset of Arctic Melt) expedition in the Fram Strait pack ice during the spring transition, 8 May to 14 June of 2023.

The primary observed data include wind speed and direction, temperature, surface temperature and downwelling long- and shortwave radiation. Measurements ran continuously during the whole expedition.

This dataset is the raw data from the weather station alone. A corresponding complete, quality controlled and user friendly dataset with corrected and averaged data is available separately. In the complete dataset, additional data are added from other measuring systems.

Citation

Sonja Murto, Michael Tjernström, Michail Karalis, John Prytherch (2024) Wind, temperature, relative humidity, surface temperature and radiation from expedition ARTofMELT, Arctic Ocean, 2023 — raw data. Dataset version 1. Bolin Centre Database. https://doi.org/10.17043/oden-artofmelt-2023-weather-station-raw-1

References

Murto S, Tjernström T, Karalis M, Prytherch J (2024) Wind, temperature, relative humidity, surface temperature and radiation from expedition ARTofMELT, Arctic Ocean, 2023. Dataset version 1. Bolin Centre Database. https://doi.org/10.17043/oden-artofmelt-2023-weather-station-1

Data description

The dataset includes 1044 consecutively numbered hourly text files (.dat) zipped into one zip-file. Total file size is about 131 MB (compressed to 34 MB).

Each file begins with a header (4 lines) and then follows one line per samples averaged over 5 seconds (~720 lines, due to timing this may vary slightly).

Variables

Primary variables are temperature, relative humidity, atmospheric pressure, downwelling short- and longwave radiation and surface temperature. GPS position and time is also included. Unrealistic values occur when sensors are disconnected.

Dimensions

Dimensions for the fields are time.

File structure

Data on each line (each sample), starting at line 5, are comma separated. Variable names are given on line 3:

• TIMESTAMP Time stamp
• RECORD Sample number
• ggautc GPS time (UTC, HHMMSS)
• ggalatitude GPS latitude (100*deg)
• ggan_s_ind GPS latitude (N/S)
• ggalongitude GPS longitude (100*deg)
• ggae_w_ind GPS longitude (E/W)
• ggaaltitude GPS altitude (m, not used, ignore)
• PSP Downwelling broadband shortwave radiation from Eppley pyranometer (W m⁻²)
• PIRnet Net longwave broadband radiation from Eppley pyrgeometer. This is the observed value w.r.t. the actual sensor temperature (W m⁻²)
• PIR Downwelling longwave broadband radiation from Eppley pyrgeometer (W m⁻²) estimated using PIRNet and the sensor temperature
• PTU_T Temperature (not used, ignore)
• PTU_RH Relative humidity (not used, ignore)
• PTU_P Atmospheric pressure (hPa, at station height)
• WSPD Wind speed relative to ship's motion (m s⁻¹) measured with heated 2D sonic instrument
• WDIR Wind direction relative to ship's motion and orientation (deg) measured with heated 2D sonic instrument
• ROT_T Temperature (°C) from separate ventilated Rotronic sensor
• ROT_RH Relative humidity (%) from separate ventilated Rotronic sensor
• KT151_T Surface temperature (°C) from IR thermometer on the forward port side of Oden
• KT152_T Surface temperature (°C) from IR thermometer on the forward starboard side of Oden

Comments

Measurement system

The data was obtained from a weather station with multiple sensors:

• Gill 2D sonic anemometer (wind direction and speed)
• Rotronic aspirated TRH for temperature and relative humidity
• Vaisala PTU pressure sensor (for air pressure)
• Eppley Precision Infrared Radiometer (PIR; downwelling and net longwave radiation)
• Eppley Precision Spectral Pyranometer (PSP; downwelling shortwave radiation)
• Two Heitronics KT15 infrared (IR) sensors mounted on the port side (heated) and starboard side (non-heated) of the rail (surface temperature)

Several errors influence this data. For example:

• At the beginning of the expedition, the portside surface temperature sensor developed noise due to water creeping into the electronics. This was repaired 22⁠ – ⁠24 May.
• Towards the end of the expedition a fan malfunctioned on the Rotronic TRH sensor on the foredeck mast. The weather station is equipped with the same sensor, and this was moved to the foredeck mast on 8 June, hence the primary temperature and relative humidity measurement on the weather station is lacking from thereon. For more details, see the readme for the processed dataset, by Murto et al. (2024).

Associated processed data

A completed concatenated and quality controlled data set mostly based on these data was created by Murto et al. (2024) and is available separately. This data set also includes additional measurements and calculations as well as quality control flags. The processing from the raw data is complex involving different types of code and calculations, also including ingesting measurements from other instruments. The codes for this is therefore not available. Contact the data creators for more information.

Data creators' roles

The instrument system was continuously logging and was monitored by the Meteorology team onboard Oden:

• Sonja Murto (operator and dataset creator)
• Ian Brooks (WP lead)
• Michail Karalis (operator)
• Michael Tjernström (chief scientist; operator)

John Prytherch (also Stockholm University) is responsible for the instrument system.

The expedition

Data were collected during the ARTofMELT 2023 expedition on board the Swedish icebreaker Oden, which was organized by the Swedish Polar Research Secretariat from 8 May through 14 June, 2023.