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CAVIAR Field Campaign Meeting, Imperial College 29/3/11 TAFTS: Water Vapour Continuum Data from the 2008 CAVIAR Field Campaign Ralph Beeby, Paul Green,

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Presentation on theme: "CAVIAR Field Campaign Meeting, Imperial College 29/3/11 TAFTS: Water Vapour Continuum Data from the 2008 CAVIAR Field Campaign Ralph Beeby, Paul Green,"— Presentation transcript:

1 CAVIAR Field Campaign Meeting, Imperial College 29/3/11 TAFTS: Water Vapour Continuum Data from the 2008 CAVIAR Field Campaign Ralph Beeby, Paul Green, Juliet Pickering

2 CAVIAR Field Campaign Meeting, Imperial College 29/3/11 Outline Introduction LBLRTM simulations TAFTS flight data LBLRTM/TAFTS comparison: Flight B400 Continuum coefficients Conclusions & further work

3 CAVIAR Field Campaign Meeting, Imperial College 29/3/11 Introduction TAFTS mounted on-board UKMO/FAAM BAe-146 for CAVIAR field campaigns Aim: to use TAFTS spectra to measure the water vapour continuum in the far-IR Method: –LBLRTM uses current model of water vapour continuum to simulate atmospheric spectra –Compare TAFTS (observed) spectra with LBLRTM (simulated) spectra –Differences between TAFTS and LBLRTM changes to continuum? Case study: flight B400, 18/09/2008, Camborne

4 CAVIAR Field Campaign Meeting, Imperial College 29/3/11 Simulating Spectra with LBLRTM LBLRTM takes 1-D atmospheric profile as input – need to estimate temperature and water vapour profiles from sondes and aircraft data Uses MT_CKD 2.5 continuum – can adjust the strength within the simulation for comparison with TAFTS data Below: spectrum for run 4 (34kft / 251mb) UW

5 CAVIAR Field Campaign Meeting, Imperial College 29/3/11 TAFTS Spectrum Run 4: 34,000ft (251mb), upwelling radiances

6 CAVIAR Field Campaign Meeting, Imperial College 29/3/11 TAFTS Spectrum: Windows Spectral features of continuum visible in windows between strong WV absorption lines Compare TAFTS and LBLRTM in windows to see where continuum needs adjustment

7 CAVIAR Field Campaign Meeting, Imperial College 29/3/11 Continuum Changes to continuum suggested by differences between TAFTS and LBLRTM

8 CAVIAR Field Campaign Meeting, Imperial College 29/3/11 Continuum (2) Some windows suggest correction of >100%

9 CAVIAR Field Campaign Meeting, Imperial College 29/3/11 Continuum (3) Currently large uncertainties associated with data Size of spread mostly due to differences between TAFTS and simulation

10 CAVIAR Field Campaign Meeting, Imperial College 29/3/11 Comparison Still parts of windows where TAFTS and LBLRTM do not agree Option 1: adjust TAFTS data Option 2: adjust simulations

11 CAVIAR Field Campaign Meeting, Imperial College 29/3/11 Fine-tuning TAFTS? Deghosting routine Finish uncertainty analysis:, T error LBLRTM? Differences between LBLRTM and observed spectra can suggest where T or WV profile need adjusting 1DVar retrieval scheme performed using ARIES data (Courtesy S Newman) - see how this affects far-IR

12 CAVIAR Field Campaign Meeting, Imperial College 29/3/11 TAFTS/ARIES Inter-comparison

13 CAVIAR Field Campaign Meeting, Imperial College 29/3/11 Conclusions & further work First corrections to continuum from B400 – hope to refine these values Improve TAFTS data with de-ghosting routine, improve simulation with adjustments to profile – retrieval Repeat for other runs – are they consistent? Compare continuum with ARIES data


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