The FAAM (Facility for Airborne Atmospheric Measurements) puts at the scientists' disposal a large atmospheric research aircraft (the BAE-146-301 aircraft) through a scheme of project selection and combined funding. It is run jointly by NERC and by the UK Met Office, and is one of the NERC Centres for Atmospheric Science (NCAS). The BADC is the FAAM designated data centre.

The CAVIAR campaign will use instruments on board the FAAM BAe-146 aircraft to determine the strength and temperature dependence of the water vapour continuum over a range of wavelengths. In doing so, the aim is to determine whether water vapour dimers, or the far wings of monomer lines, or a combination of both, are responsible for the continuum absorption, and put the continuum on a more secure theoretical footing.

The measurements will be co-ordinated with infrared ground-based sun-pointing Fourier Transform Spectrometer (FTS) observations by the National Physical Laboratory at Camborne (UK) and Jungfraujoch (Switzerland). The choice of locations has been made to enable this ground-based instrumentation to observe under very different conditions of total column water vapour, as this will allow study of different parts of the infrared spectrum.

The campaign will be part of a large consortium which includes theoretical studies of the water dimer, FTS and Cavity Ring Down measurements of continuum absorption in the laboratory and modelling studies of the impact of the continuum on the Earth's radiation budget for present day and possible future climates.

As stated in the CAVIAR Conditions of Use, access to the BAe-146 data is restricted to CAVIAR participants and to Met Office aircraft group members:

• processed core data is restricted for one year after measurement and also ruled by the FAAM Data Protocol.
• non-core data collected on board the FAAM aircraft will be restricted to CAVIAR participants and to Met Office aircraft group members for 2 years after measurement, after which the data will be released to the public domain.
• Access to the BAe-146 raw-core data is restricted to FAAM staff.

All users are requested to acknowledge the data providers in any publication based on CAVIAR data.

1. register as a BADC user — if you are already a registered BADC user, skip this step; if you have forgotten your BADC user ID and/or password, please contact the BADC helpdesk at badc@rl.ac.uk;
2. apply for access to the CAVIAR data — you will be asked to abide by the CAVIAR Conditions of Use and the FAAM Conditions of Use

If you are a member of the Met Office Aircraft users group you will already have access to this data and need not apply above.

For more details on FAAM data restrictions, please see the FAAM Data Access Rules.

BADC will store data from the FAAM BAe-146 aircraft supplied by the CAVIAR project team in the BADC FAAM archive, from where they can be viewed and downloaded by authorised users (see below). These data include both core and non-core data (for a definition of core data, see the document on FAAM Instruments).

FAAM processed core data are stored in NetCDF. Processed non-core data are stored in NetCDF or NASA Ames. Raw core data are stored in zipped VMS files. Some software to read, manipulate and convert these formats into each other are provided by the BADC (software directory in the FAAM archive) or other agencies.

CAVIAR data are stored in either NetCDF or NASA Ames format.

File names follow the BADC file name convention and (for FAAM data) the FAAM file name convention.

Services to CAVIAR Campaign participants

• A secure project workspace, accessible by FTP, has been set up for use by CAVIAR participants to facilitate the exchange of documents and preliminary data files. Please note this is separate from the data archive and validated, formatted data files should be subsequently be submitted to the ARCHIVE in the normal way.

  To gain access the FTP-project-space you will need to be registered with BADC (See 1 above) and

  • apply to the CAVIAR FTP project space and be authorised by the project management team.
  The workspace can then be accessed by FTP to proj-ftp.ceda.ac.uk directory project_spaces/caviar_ps. For help with FTP see the BADC FTP guide. Access to view and download files may be obtained via your web browser using the URL ftp://username@proj-ftp.ceda.ac.uk (you will be prompted for your password) however to upload files you will need an FTP client.

• CAVIAR Data Providers Guide to submit data to the BADC Archive.
• BADC NASA-Ames file checker
• BADC NetCDF file checker

Documentation

• Tables showing archive contents arranged by flight number/date and by campaign with links to the archive.
• FAAM Flight Schedule - Calendar of past FAAM flights based on the data archived - Updated daily.
• Tables showing which core parameters were measured for each flight.
• List of FAAM campaigns, with links to the relevant BADC FAAM dataset details and specific data access conditions.
• List of downloadable software packages to write, read and handle NetCDF files.

Links to further information

• Caviar project web page
• The Facility for Airborne Atmospheric Measurements (FAAM) Web site

References

• The CAVIAR Principal Investigators are Keith Shine (University of Reading) and Jonathan Taylor (Met Office).
• The FAAM Ops Manager is Maureen Smith.
• Any query regarding the data should be sent to the BADC help desk.