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CAVIAR flying debrief (2008) Reading 25 th November 2008

TAFTS 2008 NPL calibration and Summer flying Paul Green, Ralph Beeby, Alan Last, Caroline Cox, John Harries, Juliet Pickering Imperial College London With many diagrams taken from Stu Newman’s report. CAVIAR flying debrief (2008) Reading 25 th November 2008. Introduction. Calibration at NPL

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CAVIAR flying debrief (2008) Reading 25 th November 2008

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  1. TAFTS 2008NPL calibration and Summer flyingPaul Green, Ralph Beeby, Alan Last, Caroline Cox,John Harries, Juliet PickeringImperial College LondonWith many diagrams taken from Stu Newman’s report CAVIAR flying debrief (2008) Reading 25th November 2008

  2. Introduction • Calibration at NPL • Summer 2008 Flight campaign • Closing remarks CAVIAR flying debrief (2008) Reading 25th November 2008

  3. The TAFTS Instrument • dual-input Martin-Puplett (polarizing) FTS with two spectral bands • measure both nadir and zenith (+net) • 4 liquid helium cooled detectors • 80-300cm-1 (2 x Ge:Ga) • 300-700cm-1 (2 x Si:Sb) • resolution: 0.12cm-1 (apodized) • single scan: 2 secs • 4 internal BB sources • employs Brault sampling scheme • all built in-house (J Murray + A Canas) • UKMO C-130, ARA Egrett, BAe-146 CAVIAR flying debrief (2008) Reading 25th November 2008

  4. Radiometric calibration • At NPL 30th June – 18th July 2008 • First radiometric calibration with 2 external blackbody sources. • Differential instrument, always measures the difference between two views. • First calibration with target at -55C. (Best to date is around -40C.) • New beamsplitter (Cardiff Uni) arrived early June. One set of measurements with original BS, and one with the new one, for comparison. CAVIAR flying debrief (2008) Reading 25th November 2008

  5. NPL external calibration blackbody • Purpose-built traceable temperature standard calibrated BB for use by both TAFTS and ARIES [UKMO 3-16μm FTS] • Alcohol cooled • Temperature range • -65 to +10C • Blackbody emissivity • 0.996  0.002 (λ < 50 μm) • 0.994  0.005 (50 μm < λ < 100 μm) • 0.990 +0.005 / -0.02 (100 μm < λ < 200 μm) Eric Usadi, NPL CAVIAR flying debrief (2008) Reading 25th November 2008

  6. Summer flying 2008 • Campaign dates: 13 Aug – 25 Sept 2008 (7 weeks) • 35 flight hours = (7x 5hr flights) • All we needed were perfect clear-sky over Camborne in Cornwall….. CAVIAR flying debrief (2008) Reading 25th November 2008

  7. Flight campaign instrumentation • Camborne based instrumentation • Radiosonde balloons (temperature, water vapour profile, wind) • GPS (water vapour) • Lidar backscatter (aerosol + cloud base) • Microwave retrieved water vapour and temperature (18/09/08 only) • Microtops sun photometer (aerosol optical thickness) • NPL 0.7-14μm sun-pointing FTS • BAe-146 in-situ • Radiometers, TAFTS, ARIES, SWS • In-situ (temp, WV, wind, cloud, aerosol etc.) • Dropsondes • BBRs, surface temp, hemispherical radiance • Model fields • MO Mesoscale model, MO and ECMWF NWP models CAVIAR flying debrief (2008) Reading 25th November 2008

  8. CAVIAR 2008 Flight schedule B396 15:00UTC B397 12:00UTC SEVIRI images CAVIAR flying debrief (2008) Reading 25th November 2008

  9. B398 – Clear-skies? B398 – 22/08/08 14:42UTC B398 – 22/08/08 16:27UTC CAVIAR flying debrief (2008) Reading 25th November 2008

  10. B400 synoptic chart CAVIAR flying debrief (2008) Reading 25th November 2008

  11. B400 – SEVIRI SEVIRI image, 10:00UTC CAVIAR flying debrief (2008) Reading 25th November 2008

  12. B400 – flight track CAVIAR flying debrief (2008) Reading 25th November 2008

  13. B400 - Clouds? CAVIAR flying debrief (2008) Reading 25th November 2008

  14. B400 - Atmospheric profile data Courtesy of R. Beeby CAVIAR flying debrief (2008) Reading 25th November 2008

  15. B400 - Preliminary data • Entire flight dataset 3h20 • 08:27:25Z – 11:46:53Z • But concentrate on run 4 • 34kft (southwards heading) • 10:25:53 -10:32:52: 7minutes • Sonde launches at: • 10:26:04 #3 • 10:28:01 #4 • Simulations: sonde #3 from 75mbar below aircraft melded with 11:00 Camborne sonde (Courtesy of R. Beeby) CAVIAR flying debrief (2008) Reading 25th November 2008

  16. Up- and downwelling radiance CAVIAR flying debrief (2008) Reading 25th November 2008

  17. Up- and downwelling radiance CAVIAR flying debrief (2008) Reading 25th November 2008

  18. B400 net radiance CAVIAR flying debrief (2008) Reading 25th November 2008

  19. B400 – other runs Red dots – Camborne overpasses CAVIAR flying debrief (2008) Reading 25th November 2008

  20. Closing remarks • NPL calibration • Campaign in UK August/September 2008 • LW data fundamentally sound… SW still to access • Future work: • Work on NPL calibration data to determine ε and ΔT of blackbodies • New Cardiff-made BS analysis • Final data calibration – with uncertainties • Cross-calibration with ARIES • Determination of far-IR water vapour continuum coefficients CAVIAR flying debrief (2008) Reading 25th November 2008

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