Title: CAVIAR
1CAVIAR Continuum Absorption by Visible and
Infrared Radiation and its Atmospheric Relevance
PI Keith Shine Department of Meteorology,
University of Reading Co-Is Stephen Ball
Department of Chemistry, University of
Leicester Tom Gardiner National Physical
Laboratory Roderic Jones Department of Chemistry,
University of Cambridge John Harries, Juliet
Pickering Blackett Laboratory, Imperial College
London Kevin Smith Rutherford Appleton
Laboratory, STFC Jonathan Taylor and Stuart
Newman Met Office Jonathan Tennyson Department of
Physics, University College London Co-ordinator
Igor Ptashnik Dept of Meteorology, Univ of
Reading And (roughly!) 5 post-doc researchers and
3 PhD students
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3 We know
- Water vapour is by far the most important
greenhouse gas in the atmosphere we know it is
important for remote sensing we know it is an
important contributor to climate feedbacks
We also know
- That it possesses a radiatively-important
continuum, pervasive from the visible to
microwave, which is represented in many models in
a semi-empirical way, using observations from a
limited number of wavenumbers and measurement
conditions
4Major Aims
- Describe the continuum across a broad wavelength
range and a broad range of atmospheric and
near-atmospheric conditions, using both
laboratory and field measurements - Explain the underlying cause of the continuum
can we separate out far-wing line shape
contributions from dimer explanations? - Provide the community with an improved continuum
model (perhaps in a CKD-like form)
Measurements
5The Programme
WP1 Molecular Modelling
WP2 Laboratory Measurements
WP3 Field Measurements
WP4 Synthesis Everyone!
WP5 Impact on Understanding
WP6 Provision of model for wider use Everyone!
6The work flow
Work commenced
Work soon commencing!
7The Project
- Formally, we started on 1 October 2006 will
formally end 30 June 2011 (including a no-cost
extension) - Annual meetings with international involvement
8Major progress in second year 1
- Development of a new potential energy surface for
water dimer, which will allow improved ab-initio
calculations of its spectra - Analyses of new laboratory measurements to derive
the continuum across the near-infrared
9Major progress in second year 2
- Advances in the broadband cavity-ringdown and
cavity-enhanced methodologies and new results - A major calibration exercise so that all CAVIAR
field instrumentation are now traceable to the
same standard
10Major progress in second year 3
- A major field campaign using aircraft and
ground-based high-spectral resolution
spectrometers, plus supporting data
Photo from Liam Tallis
11Challenges for third year 1
- Production of new ab initio dimer spectrum and
comparison with measurements - New laboratory measurements using both
traditional FTS and cavity a particular
emphasis will need to be on the between-band
absorption, as this is most important for the
AR in CAVIAR
12Challenges for third year 2
- Analysis of new laboratory measurements
- Full analysis of calibration of field instruments
- Full analysis of Camborne Field Campaign
- The second field campaign at Jungfraujoch in
summer 2009
13Challenges for third year 3
- Begin serious work on the three remaining
workpackages - Synthesis of lab and field measurements and
theoretical work - Modelling the impact of the continuum on the
radiation balance - Developing a continuum model for community use
Clough et al. J.Geophys.Res, 1992
14Conclusions
- In Year 2, we have made significant progress in
model and instrument development, acquired and
analysed new laboratory data, performed the major
Camborne field experiment, and have advanced
plans for the Jungfraujoch 2009 campaign - The legacy of the project
- - extensive new set of observations over a
wide range of conditions in both lab and field - - new physically-based continuum model with
wide range of potential users in basic science,
in weather and climate prediction and in remote
sensing - - cohort of post-docs and students trained in
a cross-disciplinary environment