Dataset
905 nm Vaisala CT75K Lidar Ceilometer Data from the Chilbolton Facility for Atmospheric and Radio Research (CFARR) site, Hampshire, England, 1996 - present
Abstract
The Chilbolton Observatory, Hampshire, have had a Vaisala CT75K lidar ceilometer deployed since 13th September 1996. This dataset contains measurements of the range of first, second, and third cloud base from the lidar and attenuated backscatter coefficients of aerosols within the atmosphere. Plots of the attenuated backscatter coefficient at different heights are also available.
The instrument has been regularly calibrated using the method described by O'Connor, Ewan J., Anthony J. Illingworth, Robin J. Hogan, 2004: A Technique for Auto-calibration of Cloud Lidar. J. Atmos. Oceanic Technol., 21, 777–786. doi: http://dx.doi.org/10.1175/1520-0426(2004)021<0777:ATFAOC>2.0.CO;2 .
Prior to April 2014 this technique had been applied manually, but from 2014 this was automated to provide a routine, automated application of O'Connor et al's calibration technique. This also highlighted an instrument calibration drift not previously spotted in earlier data and so a corrected data have been added to the archive for the following periods (denoted by "_cor1" in the filename): 1st July 2003 – 31st December 2003, January 2006 to December 2012 and February and March 2013. Users should see the data quality notes for further details.
This dataset incorporates the earlier published and citable 1996 - 2013 collection of lidar data, but continues this dataset to present
Details
| Previous Info: |
No news update for this record
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| Previously used record identifiers: |
No related previous identifiers.
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| Access rules: |
Access to these data is available to any registered CEDA user. Please Login or Register for an account to gain access.
Use of these data is covered by the following licence: http://www.nationalarchives.gov.uk/doc/open-government-licence/version/3/. When using these data you must cite them correctly using the citation given on the CEDA Data Catalogue record. |
| Data lineage: |
Data are recorded continuously by the instrument at the Chilbolton site before post-processing using signals from optically thick strato-cumulus clouds to calibrate according to the method described by O'Connor, Ewan J., Anthony J. Illingworth, Robin J. Hogan, 2004: A Technique for Auto-calibration of Cloud Lidar. J. Atmos. Oceanic Technol., 21, 777–786. doi: http://dx.doi.org/10.1175/1520-0426(2004)021<0777:ATFAOC>2.0.CO;2. The data are then deposited at the BADC for ingestion into the BADC archives. |
| Data Quality: |
Data are checked by CFARR staff prior to submission to BADC
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| File Format: |
Data are netCDF formatted
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Related Documents
Process overview
Instrument/Platform pairings
| Chilbolton Facility for Atmospheric and Radio Research (CFARR) 905 nm Vaisala CT75K Lidar Ceilometer | Deployed on: Chilbolton Atmospheric Observatory (CAO) |
| Output Description | None |
- units: m-1 sr-1
- long_name: Attenuated backscatter coefficient
- var_id: beta
- units: mV
- var_id: background
- long_name: Background light
- var_id: time
- long_name: Decimal hours UTC since midnight
- units: degrees
- var_id: elev
- long_name: Elevation above horizon
- units: m
- var_id: altitude
- long_name: Height of instrument above mean sea level (Ordnance Survey Great Britain)
- units: 1
- var_id: flags
- long_name: Instrument flags
- units: %
- var_id: laser_energy
- long_name: Laser pulse energy
- units: degrees C
- var_id: laser_temp
- long_name: Laser temperature
- units: nm
- var_id: wavelength
- long_name: Lidar wavelength
- units: %
- var_id: scale
- long_name: Measurement scale - should be 100%
- var_id: bases
- long_name: Number of cloud bases
- units: 1
- var_id: pulses_per_profile
- long_name: Number of laser pulses averaged per profile
- long_name: Range Of The First Cloud Base From The Lidar
- names: Range Of The First Cloud Base From The Lidar
- var_id: range
- units: km
- long_name: Range from lidar
- units: km
- var_id: base1
- long_name: Range of the first cloud base from the lidar
- units: km
- var_id: base2
- long_name: Range of the second cloud base from the lidar
- units: km
- var_id: base3
- long_name: Range of the third cloud base from the lidar
- units: m-1 sr-1
- var_id: beta_raw
- long_name: Raw attenuated backscatter coefficient
- units: %
- var_id: receiver_sens
- long_name: Receiver sensitivity
- units: m-1 sr-1
- var_id: stdn
- long_name: Standard deviation of the backscatter coefficient background noise
- units: mV
- var_id: window
- long_name: Window contamination
Co-ordinate Variables
- units: degrees_north
- standard_name: latitude
- var_id: latitude
- long_name: Latitude of lidar
- units: degrees_east
- standard_name: longitude
- var_id: longitude
- long_name: Longitude of lidar
Temporal Range
1996-09-12T23:00:00
Ongoing
Geographic Extent
51.1450° |
||
-1.4270° |
-1.4270° |
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51.1450° |