HALO lidar vertical stare data from expedition ARTofMELT, Arctic Ocean, 2023
Ian Brooks, Heather Guy
Lidar backscatter and Doppler velocity measurements from the HALO lidar for periods pointing vertically upwards.
Backscatter intensity provides information on vertical structure of aerosol and cloud particles. Doppler velocity provides information on vertical air motion, potentially biased by particle fall velocity where that is significant.
The lidar was installed on top of a container on the foredeck of Oden, approximately 13 m above sea level. The lidar operated continuously, but the vertical stare data is discontinuous, with gaps where wind profile or RHI scans were underway.
Data was collected during the ARTofMELT 2023 expedition with Swedish icebreaker Oden in the Fram Strait pack ice during the spring transition (8 May to 14 June) of 2023.
AtmosphereObservationsLidarDopplerAerosol backscatterDoppler velocityAir motionArcticArctic OceanARTofMELTARTofMELT 2023 expeditionIcebreaker Oden
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Citation
References
Edson JB, Hinton AA, Prada KE, Hare JE, Fairall CW (1998) Direct Covariance Flux Estimates from Mobile Platforms at Sea. Journal of Atmospheric and Oceanic Technology 15:547–562. https://doi.org.10.1175/1520-0426(1998)015<0547:DCFEFM>2.0.CO;2
Data description
The data are provided in 35 NetCDF (nc) files.
Total size: 45 GiB.
Files are named as, for example
ncas-lidar-dop-1_Oden_stare_20230509.nc
where the data sampling date is included in the file name.
Variables
timeseconds since 00:00:00 01-01-1970 [time]doyDecimal day of year (in UTC) [time]yearYear [time]monthMonth of the year [time]dayDay of the month [time]hourHour of the day (in UTC) [time]minuteMinutes of the hour [time]secondSeconds of the minute [time]heightHeight above surface (m) [height]betabackscatter (m-1 sr-1) [time,height]SNRsignal to noise ratio () [time, height]DopplerDoppler velocity along beam (+ve away from lidar) (m s-1) [time,height]Vplatform velocity along beam (+ve away from lidar) (m s-1) [time]wvertical velocity corrected for platform motion (= Doppler + V) (m s-1) [time, height]latlatitude (degrees N)lonlongitude (degrees E)
Comments
Measurement system
The HALO lidar operated continuously throughout the campaign, conducting 3 different scan patterns in rotation:
RHI scans (oriented into wind as much as possible) every 15 minutes; a 6-point conical (VAD) scan to provide wind profiles every 30 minutes (primarily as near-real-time measurements of relative wind direction to aid orientation of RHI scans); a vertical stare when other scans were not running This data set provides vertical stare data only. RHI and VAD scan data are provides as separate data sets.
An XSENS MTi-700-G motion sensor is attached to, and aligned with, the lidar reference frame. 10Hz data (3-axis rotation rates and acceleration) from the XSENS motion pack is combined with low rate (0.2 Hz) heading and horizontal velocity data from the ship navigation system to calculate a high-rate attitude (pitch, roll, heading) and 3-dimensional velocity components following Edson et al. (1998). These are used to correct the individual Doppler velocity measurements for the component of platform motion along-beam. Motion is significant only when the ship is underway.
Data creators
- Ian Brooks: principle investigator, operator, and data set creator
- Heather Guy: operator
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.
Project
ARtofMELT 2023 expedition. The project ARTofMELT was funded by the Swedish Research Council (VR: 2022-03052). University of Leeds contribution was funded by the UK Natural Environment Research Council (grant: NE/X000087/1). The HALO lidar was provided by the Atmospheric Measurement and Observation Facility (AMOF) of the National Centre for Atmospheric Science (NCAS), a Natural Environment Research Council (UKRI-NERC) funded facility.
Publisher
Bolin Centre Database
License
Open Data Commons Attribution License (ODC-By) v1.0
First name
Ian
Last name or organisation
Brooks
Email address
Address
School of Earth and Environment; University of Leeds
Postal code
LS2 9JT
City
Leeds
Country
United Kingdom
GCMD science keyword
Earth science > Atmosphere
GCMD location
Ocean > Arctic Ocean
Dataset language
English
Begin date
2023-05-09
End date
2023-06-12