Visibility, precipitation and present weather observations from expedition SAS, Arctic Ocean, 2021
John Prytherch, Sonja Murto, Michael Tjernström
Horisontal visibility, precipitation rate and air temperature data are obtained from a Present Weather observation station. The dataset also includes the World Meteorological Organization (WMO) synop code 'present weather', which is derived from the primary variables, and a few other derived variables showing accumulated precipitation.
The Present Weather observation station was deployed on the 7th top deck of the Swedish icebreaker Oden during the expedition SAS (Synoptic Arctic Survey) covering a large area including parts of Amundsen Basin, Nansen Basin, the North Pole, Lomonosov Ridge, Morris Jesup Rise and the Yermak Plateau. Measurements ran continuously between July 27 and September 13, 2021.
AtmosphereWeather observationsVisibilityPrecipitationPresent weatherTemperatureMeteorologyArcticArctic OceanSynoptic Arctic SurveySAS 2021 expeditionIcebreaker Oden
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Data description
The dataset includes two NetCDF (.nc) files zipped into one zip-file. Total file size is about 4.7 MB (compressed 1.1 MB).
There is an associated readme_ACAS_SAS2021_PWD_v1.0.rtf file that provides a list of all variable names, with short explanations and units, WMO code definitions and further details of data and processing.
Variables
Primary variables are:
- visibility range
- precipitation rate
- temperature
Based on this established weather codes and accumulated precipitation are generated.
Dimensions
Dimensions for the fields are time.
The two NetCDF files have the following different time resolutions:
ACAS_SAS2021_PWD_1min_v1_0.nc: 1 minute time averaged dataACAS_SAS2021_PWD_20min_v1_0.nc: 20 minute time averaged data
The data was concatenated from the native format and averaged when necessary.
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 for removal of unnecessary variables.
Data creators' roles
The instrument system was continuously logging and was monitored by the Stockholm University Meteorology team onboard Oden:
- John Prytherch (operator and dataset creator and responsible for the instrument system)
- Sonja Murto (operator)
- Michael Tjernström (PI)
The expedition
The data were collected in summer 2021 from Swedish icebreaker Oden during the Synoptic Arctic Survey (SAS) 2021 expedition organized by the Swedish Polar Research Secretariat.
Project
Synoptic Arctic Survey (SAS) 2021 expedition. These data are part of the Arctic Climate Across Scales (ACAS) project, funded by the Knut and Alice Wallenberg Foundation (grant no. 2016-0024). Project PI Michael Tjernström (MISU).
Publisher
Bolin Centre Database
License
First name
John
Last name or organisation
Prytherch
Email address
Address
Department of Meteorology; Stockholm University
Postal code
SE-106 91
City
Stockholm
Country
Sweden
GCMD science keyword
Earth science > Atmosphere
GCMD location
Ocean > Arctic Ocean
Dataset language
English
Begin date
2021-07-27
End date
2021-09-13