Ceilometer backscatter, cloud base height and cloud fraction data from the Arctic Ocean 2016 expedition

John Prytherch, Michael Tjernström, Ian Brooks

Measurements of cloud base height, cloud fraction and backscatter profiles.

The dataset provides rare high quality meteorological observations from sea-ice regions of the Arctic Ocean. They enable analysis of meteorological conditions and provide context for other measurements and analysis associated with the expedition.

The measurements are from the CL51 ceilometer operating on Icebreaker Oden’s 7th deck at 25 m above sea level during the Arctic Ocean 2016 (AO2016) expedition to the central Arctic Ocean in August and September 2016.

AtmosphereObservationsCloud-base heightCloud fractionBackscatter profileMeteorologyArctic boundary layerArctic cloudsHigh ArcticArctic Ocean 2016AO2016AO16ACASOden

Name

Version

Citation

Data description

Data from the FMI Vaisala CL51 ceilometer, averaged over either 1 or 30-minute intervals. Two data formats are available: Matlab (.mat) and NetCDF (.nc), with an accompanying readme (.rtf) file.

Comments

The height to the lowest cloud base, and up to two additional cloud bases when the lowest cloud layer does not cover the whole sky, was measured by a Vaisala CL51 ceilometer, located above Oden’s bridge on the 7th deck. The ceilometer, owned by the Finnish Meteorological Institute (FMI), was deployed as part of the Stockholm University weather station.

The system uses a proprietary Sky Condition algorithm to determine cloud fraction at up to five levels, converting single-point time-series measurements to time-averaged area coverage. The system additionally recorded the backscatter profile, and hence serves as a so-called poor-man’s LiDAR. When the attenuation of the laser beam reaches a threshold, like in a dense fog, it switches to reporting vertical visibility, rather than cloud-base height.

Data from the ceilometer are combined into a cruise-length file. The data are time-averaged to both 1-minute and 30-minute intervals, to correspond with the micrometeorological averaging periods used for the mast sensors.

Coordinates (lat, lon) for the observations are not included in this dataset, but they are the same as in the Weather data from MISU weather station during the Arctic Ocean 2016 expedition.

More information about the Canadian-Swedish Arctic Ocean 2016 expedition is available from the Swedish Polar Research Secretariat.

Version history

Version 2.0

Essentially the same data as in version 1.0, but with an updated readme file and new metadata within the nc files.

Version 1.0

Initial release.

Project

Arctic Ocean 2016 expedition. These data were processed as part of the Arctic Climate Across Scales (ACAS) project, funded by the Knut and Alice Wallenberg Foundation. Project PI Michael Tjernström (MISU).

Publisher

Bolin Centre Database

First name

John

Last name or organisation

Prytherch

Email address

john.prytherch@misu.su.se

Address

Department of Meteorology (MISU); 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

2016-08-10

End date

2016-09-18

DOI

Time

Versions

• 2 2022-01-26T13:47:46.62531+00:00
• 1 2022-01-26T13:47:46.048776+00:00
• 2 2021-12-03T16:09:29.697037+00:00
• 1 2021-12-03T16:09:29.692144+00:00
• 2 2021-10-29T06:23:11.905354+00:00
• 2 2021-10-26T09:28:55.367236+00:00
• 2 2020-03-11T08:43:46.011371+00:00
• 2 2020-03-11T08:43:46+00:00
• 1 2019-09-09T16:43:18.042026+00:00
• 1 2019-09-09T16:43:18+00:00