Sonja Murto, Michael Tjernström, Michail Karalis, John Prytherch
Horisontal visibility, precipitation rate and air temperature data are obtained from a Present Weather observation station deployed on the 7th top deck of the Swedish icebreaker Oden during the expedition ARTofMELT (Atmospheric Rivers and the Onset of Arctic Melt) in the Fram Strait pack ice during the spring transition, 8 May to 14 June of 2023. Measurements ran continuously during the whole expedition.
The dataset also includes the World Meteorological Organization (WMO) synop code 'present weather', which is derived from the primary variables.
This dataset is the raw data from the instrument. A corresponding concatenated user friendly dataset with raw and averaged data is available separately.
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Citation
Sonja Murto, Michael Tjernström, Michail Karalis, John Prytherch (2024) Visibility, precipitation and present weather observations from expedition ARTofMELT, Arctic Ocean, 2023 — raw data. Dataset version 1. Bolin Centre Database. https://doi.org/10.17043/oden-artofmelt-2023-present-weather-raw-1
References
Sonja Murto, Michael Tjernström, Michail Karalis, John Prytherch (2024) Visibility, precipitation and present weather observations from expedition ARTofMELT, Arctic Ocean, 2023. Dataset version 1. Bolin Centre Database. https://doi.org/10.17043/oden-artofmelt-2023-present-weather-1
Sonja Murto, John Prytherch (2024) Scripts for quality control and creating netCDF files from present weather sensor observations from the expedition ARTofMELT, Arctic Ocean, 2023. Software version 1.0.0. Bolin Centre Code Repository. https://doi.org/10.57669/oden-artofmelt-2023-present-weather-1.0.0
Data description
The dataset includes 907 raw hourly text files (.PWD) zipped into one zip-file. Each text file contains the sequence of Messages from the Vaisala PDW22 instrument. Total file size is about 21 MB (compressed 2.4 MB).
Variables
Primary variables are visibility range, precipitation rate and temperature. Based on this established weather codes are generated.
Dimensions
Dimensions for the fields are time.
File structure
This is the raw data in the instrument native format. Each data point consists of three ascii text lines; all starting with time stamp. The first line then includes start-of-record, instrument name, error flags, and then the variables (visibility 1 and 10 minute averages), four weather codes, three precipitation values (total rate, accumulate total and snow), temperature and an empty variable (/////). Then follows two lines with only the time stamp; the last ending with end-of-message.
Comments
Measurement system
The data was obtained from a Present Weather Detector sensor from Vaisala (Vaisala PWD22). Visibility is measured with a laser using forward scattering as the WMO standard, the greatest distance at which it would be just possible to see and identify a prominent dark object against the sky at the horizon with the unaided eye. The precipitation comes from a Vaisala RAINCAP sensor, an acoustic sensor that measures the impact of individual raindrops on a smooth stainless steel surface using a piezoelectric detector. Weather codes are determined from this information and the temperature, measured with a platinum-resistance sensor in an unventilated radiation shield.
Quality control
No data quality control is applied except excluding corrupt messages.
Associated processed data and code
Unpacked and concatenated, and some time averaged, data in NetCDF format is derived from this dataset and created by Murto et al. (2024). The computer codes, in Matlab and Python, written by Murto and Prytherch (2024), used to derive the final NetCDF data set from the raw data files are also available.
Data creators' roles
The instrument system was continuously logging and was monitored by the Stockholm University Meteorology team onboard Oden:
- Sonja Murto (operator and dataset creator)
- 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.