© Crown copyright 2007 CAVIAR flight plans Stuart Newman, Met Office, Exeter, UK

© Crown copyright 2007 FAAM BAe capability Blister containing ARIES and other radiometers ARIES interferometer (Bomem MR200) Spectral range cm -1 HgCdTe and InSb detectors Max. resolution 1 cm -1 (0.5 cm -1 sampling) Multiple viewing geometries (up and down) Field of view 44 mrad (full angle) Dropsondes Core chemistry (ozone and CO) Temperature and humidity probes Multi-spectral shortwave radiometer Microwave radiometers Particulates (aerosols and cloud particles) Winds (and more…) Endurance 5½ hours Altitude 20 m – 10.5 km

© Crown copyright 2007 Making the most of the observations Methodology for Camborne field campaign Key questions:  Do we combine flying over ocean (stable surface emission) with flying over Camborne? Can we do both in one sortie?  Do we fly to intercept line-of-sight of NPL solar-tracking FTS?  Do we fly in coincidence with satellite overpasses, e.g. IASI interferometer on MetOp?  What heights do we need to fly at in order for aircraft interferometer measurements to be of maximum value?  Do ARIES and TAFTS have differing requirements?

© Crown copyright 2007 Observations versus simulations Methodology for Camborne field campaign surface Skin temperature (runs at low level)  Accurate interferometer measurements combined with a well-characterised atmospheric state are essential requirements  Need frequent dropsonde profiling (temperature and water vapour) in addition to Camborne radiosonde launches  Need ARIES and TAFTS to view both upwelling and downwelling radiances at a series of heights in the atmosphere

© Crown copyright 2007 Case study day: 5 September 2004 High pressure subsidence implying clear skies

© Crown copyright 2007 Case study day: 2 September 2005 High pressure subsidence implying clear skies

© Crown copyright 2007 Case study day: 7 September 2006 High pressure subsidence implying clear skies

© Crown copyright 2007 Aircraft brightness temperatures (nadir) Window regions sensitive to the self continuum show very little change with altitude Stronger water vapour bands (foreign continuum) show much greater dependence on altitude in the nadir TAFTSARIES CO 2 O3O3 strong H 2 OCO 2 strong H 2 O weak H 2 O

© Crown copyright 2007 Aircraft brightness temperatures (zenith) Window regions more sensitive to the self continuum when viewing in the zenith Stronger water vapour bands (foreign continuum) still vary with altitude Very cold brightness temperatures (cold radiances) are challenging to measure TAFTSARIES CO 2 O3O3 strong H 2 O CO 2 strong H 2 O weak H 2 O

© Crown copyright 2007  BT calculations with height Line-by-line calculations for each of the three case study days at different altitudes Calculate upwelling and downwelling radiances See how radiance (brightness temperature) varies with height 300 hPa  BT

© Crown copyright 2007  BT (nadir spectra) Window regions show almost no change in brightness temperature with height Stronger water vapour bands show changes of several K with increasing height Dependence on water vapour profile is evident

© Crown copyright 2007  BT (zenith spectra) Window regions now show a large change in brightness temperature with height, weighted towards the lower atmosphere Stronger water vapour bands dependence weighted towards higher atmosphere Dependence on water vapour profile is again evident

© Crown copyright 2007 Location of Camborne radiosonde station 5 mi

© Crown copyright 2007 Zoom of Camborne radiosonde station 50 m

© Crown copyright 2007 NPL FTS view geometry w.r.t. solar zenith  zen (SZA) FTS Take e.g. 1 September 2008 GMTSZARun  45.1 km            59.8 FAAM 146 (height 10 km) NB. 9 km run for FAAM aircraft  1 minute 60 km run  6 minutes

© Crown copyright 2007 Water vapour measurements are key We should have a comprehensive set of water vapour instruments on board the FAAM 146 (General Eastern, FWVS, CVI and Total Water Lyman-a, SAW hygrometer) We should work out the best strategy for dropping sondes (good coverage in time and space) During straight and level runs (where instruments have time to equilibrate) we should get a good estimate of variability and uncertainty in water vapour measurements We have the option of “chasing” a radiosonde during a spiral ascent to directly compare with aircraft kit 1d-VAR retrievals of water vapour from ARIES spectra are now possible (useful for seeing structure in water vapour above and below the aeroplane) MARSS channels also sensitive to water vapour

© Crown copyright 2007 Flying details We now have more flight hours for Camborne (37.5), ~ 7 full flights The aircraft is available for CAVIAR between 13/8/08 and 25/9/08 We have the option of a refuel at a local airfield (St Mawgan) if the science dictates longer on task The are “Danger Areas” (for military use) to the south of Camborne, so operating to the north and west seems sensible

© Crown copyright 2007 Example sortie (for discussion) Assumes refuel before transit back to Cranfield Take off from Cranfield (mins) Transit to Camborne area45 Run at FL250 over site (+ turn)12 Profile down 5000 feet5 Run at FL200 (+ turn)12 Profile down 5000 feet5 Run at FL150 (+ turn)12 Profile down 5000 feet5 Run at FL100 (+ turn)12 Profile down 2500 feet5 Run at FL075 (+ turn)12 Profile down 2500 feet5 Run at FL050 (+ turn)12 Profile down 2500 feet5 Run at FL025 (+ turn)12 Profile down to 50 feet over sea5 Run over sea at 100 feet (+ turn)12 Transit back to Cranfield(45) Total flight time327 Drop in to St Mawgan for refuel25 Run at FL320 (+ turn)12 Profile up 7000 feet7 Run at FL250 (+ turn)12 Profile up feet10 Run at FL150 (+ turn)12 Profile up 5000 feet5 Run at FL100 (+ turn)12 Profile up 3000 feet5 Run at FL070 (+ turn)12 Profile up 3000 feet5 Run at FL040 (+ turn)12 Profile up1500 feet5 Run at FL025 (+ turn)12 Profile up 250 feet5

© Crown copyright 2007 Other signatures to look for? At what stage might ab initio calculations tell us where we might see dimer features? Do these occur in the mid-IR/far-IR? We think the temperature dependence of the continuum is important to distinguish between dimer and line-wing theories (so probing different temperatures in the atmosphere is necessary) Evidence from case studies (M. Matricardi, ECMWF) that agreement with continuum models (CKD2.4, MT_CKD) depends on water vapour loading, so will be useful to probe fairly moist versus fairly dry cases

© Crown copyright 2007 Thankyou Any questions?