Cloud radar data from expedition SAS, Arctic Ocean, 2021
John Prytherch, Sonja Murto, Michael Tjernström
Measurements of clouds were obtained from the RPG-Radiometer Physics RPG-FMCW-94 Doppler cloud radar. Data include radar backscatter intensity, mean Doppler vertical velocity, Doppler velocity spectral width and liquid water path in addition to complementary diagnostic variables and radar settings.
The radar was deployed on the roof of a container on the 4th 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. The radar was mounted on a gimbal to keep the radar beam pointing vertically at all times. Measurements ran continuously between July 31 and September 16, 2021.
AtmosphereCloudsWeather observationsCloud radarRadar backsactter profilesRadar Doppler velocityMeteorologyArcticArctic OceanSynoptic Arctic SurveySAS 2021 expeditionIcebreaker Oden
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Data description
This dataset is a zipped file containing approximately 1100 NetCDF (.nc) files, one file per hour, 2021-07-31 to 2021-09-16 inclusive. The total file size is about 15 GB (compressed 6.2 GB), or ~13 MB per hourly file.
Each file contains 60 variables with primary dimensions of 'range' and 'time', where 'range' is the distance from instrument to centre of each range bin. The range dimension is divided into 3 segments corresponding to the three 'chirps' emitted by the radar (C1, C2, and C3) with the range-dependent variables also divided into 3 with a corresponding chirp prefix.
The primary variables for most users are:
- radar reflectivity factor (ZE)
- mean Doppler vertical velocity (MeanVel)
- Doppler velocity spectral width (SpecWidth)
- liquid water path (LWP)
- time
- heights
Additional variables include:
- surface weather station measurements
- radar settings
- diagnostics
- spectral statistics
All variables and units can also be found by exploring any of the the NetCDF files.
Comments
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.
Measurement system
The data was obtained from a RPG-Radiometer Physics RPG-FMCW-94 Doppler cloud radar, a so-called Frequency Modulated Continuous Wave radar, meaning that the radar transmits energy continuously rather than sending discrete pulses. This improves the low-level coverage, as a regular puling radar cannot receive while transmitting, thereby extending the height to its first range gate. The results are sampled using frequency modulation, controlled by so-called "chirps". The radar was programmed such that each profile consists of three chirps, each with their own defined height ranges, vertical resolution and Doppler range and resolution. These settings were selected to prioritize high resolution reflectivity in the lower 2000 m. The chirp settings are included in the data files (with the dimension chirp_sequence).
Quality control
Quality control has not been applied to this dataset.
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 > Clouds
GCMD location
Ocean > Arctic Ocean
Dataset language
English
Begin date
2021-07-31
End date
2021-09-16