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Overview of Camborne, UK and Jungfraujoch, Switzerland Field Campaigns
CAVIAR Annual Meeting
15th Dec 2009, Abingdon
Marc Coleman, Tom Gardiner, Nigel Swann (NPL)
Liam Tallis (University of Reading)
Stuart Newman, Jonathan Taylor (Met Office)
Paul Green, Ralph Beeby, Juliet Pickering (Imperial College)
+ FAAM team
Monday, April 10, 2023
2
Background• Field measurements of water vapour continuum
required to help validate modelling work• Key instruments radiometrically calibrated at NPL
prior to each measurements campaign– Two instruments for airborne measurements (mounted on
the FAAM BAe146 aircraft)– One instrument for ground-based measurements
• Two measurement campaigns carried out– Camborne, UK: Low altitude – wet– Jungfraujoch, Switzerland: High altitude – dry
• Carried out at high and low altitude sites so that it is possible to access the centre of water bands, which facilitates characterisation of the dependence of the continuum on water abundance
Monday, April 10, 2023
3
Key Instruments(1): TAFTS and ARIES
• Both instruments passive Fourier transform infrared (FTIR) spectrometers
• TAFTS (Imperial College)– Measures difference
spectrum between nadir and zenith views
– 4 internal black bodies. One warm and one cold for each view
• ARIES (Met Office)– Can measure nadir and
zenith (not a difference measurement)
– Internal black bodies
TAFTS – tropospheric airborne Fourier transform spectrometer
ARIES – airborne research interferometer evaluation system
Monday, April 10, 2023
4
Key Instruments(2): NPLs High Resolution FTIR
• Instrument is a Bruker IFS125M FTIR augmented with NPL optics
• Unlike TAFTS and ARIES system is active– Uses sun as a light source– Interfaced with a solar tracker to track sun
• Capable of resolutions of up to 0.0035 cm-1
• Broad spectral coverage
Solar tracker
Monday, April 10, 2023
5
Radiometric Calibration of TAFTS & ARIES
• TAFTS and ARIES calibrated using a custom built black body – CAVIAR Black Body (CBB)– -80 to +40°C temp. range– Traceable to the primary radiometer (method by which the Candela is realised
in the UK)
Grooves for ethanol coolant
CAVIAR Black Body (CBB)
TAFTS
Monday, April 10, 2023
6
Radiometric Calibration of NPL FTIR
• For active FTIR use NPLs ultra high temperature black body– ~3000K– Used to realise the primary radiance scale in the UK– Traceable to the primary radiometer (as is the CBB)
• All three instruments traceable, therefore have comparability
Monday, April 10, 2023
7
Facility for Airborne Atmospheric Measurements (FAAM)
• After calibration TAFTS & ARIES re-installed on FAAM plane for first CAVIAR field trial
• Also on-board:– Chilled mirror dew
point– Total water Lyman-
– Fluorescence water
vapour sensor– SAW hygrometer– CVI hygrometer– dropsondes
Rosemount temp probes
Cloud Physics Probes
Cloud Physics Probes
SHIMS
SHIMS
Rearward and Downward Video Cameras
Short-wave spectrometer (0.3 – 1.7µm)
Microwave radiometers
Aries Interferometer (3-16 µm)
TaftsInterferometer (10 to 125 µm)
Broad band radiometers
Lidar Dropsondes
Rosemount temp probes
Cloud Physics Probes
Cloud Physics Probes
SHIMS
SHIMS
Rearward and Downward Video Cameras
Short-wave spectrometer (0.3 – 1.7µm)
Microwave radiometers
Aries Interferometer (3-16 µm)
TaftsInterferometer (10 to 125 µm)
Broad band radiometers
Lidar Dropsondes
Rosemount temp probes
Cloud Physics Probes
Cloud Physics Probes
SHIMS
SHIMS
Rearward and Downward Video Cameras
Short-wave spectrometer (0.3 – 1.7µm)
Microwave radiometers
Aries Interferometer (3-16 µm)
TaftsInterferometer (10 to 125 µm)
Broad band radiometers
Lidar Dropsondes
Monday, April 10, 2023
8
Camborne Field Trial• August – September 2008• FAAM flew out of Cranfield base• NPL FTIR & Reading
MICROTOPS (aerosol optical thickness) based at Camborne Met Office site
• Other relevant instrumentation at Camborne– Routine sonde launches from
Camborne at 11:15 and 23:15 U.T.
• Additional launches made on ‘good’ measurement days
– GPS water vapour column– Laser cloud base and visibility– Surface dew point
NPL FTIR
Sonde launch
Monday, April 10, 2023
9
FAAM Flights over Camborne• South east inaccessible due to military
operations• Operated mainly starting from north and
west– Allowed runs at low level over sea providing
surface temperature and emissivity data
• Runs of 40 nautical miles lasted ~10min at 10,000 feet
• Polygon FAAM accents (“balloon chasing”) will allow comparison between sonde and FAAM water vapour measurements
Monday, April 10, 2023
10
Camborne Water Vapour Profiles
• Aircraft straight and level runs divided into three sections: Camborne and northern and southern areas over ocean
• (Corrected) radiosonde and dropsonde profiles were used as the nearest coincident measurements of temperature and water vapour
• ECMWF analysis and forecast fields were used to account for changes in air mass with time and distance, allowing the sonde profiles to be modified accordingly
• Similar process is being undertaken for the Jungfraujoch measurements
Monday, April 10, 2023
11
Camborne Flights
• A typically “British” summer!• On 22nd Aug a double flight was possible, although throughout the day
broken cloud caused occasional obstruction• However, 18th Sep saw excellent clear sky conditions, hence so far
analysis has focussed on this day• nb. silver lining to fewer flights than planned was that additional flights
were available for the Jungfraujoch field trial
= aborted flight
= successful flight
AU G U S T 2008Sunday Monday Tuesday Wednesday Thursday Friday Saturday
1 2
3 4 5 6 7 8 9
10 11 12 13 14 15 16
17 18 19 20 21 22 23
24 25 26 27 28 29 30
31 Notes:
© 2007 Vertex42 LLC http ://w w w .vertex42.com
S M T W Th F Sa1 2 3 4 5
6 7 8 9 10 11 1213 14 15 16 17 18 1920 21 22 23 24 25 2627 28 29 30 31
J uly 2008S M T W Th F Sa
1 2 3 4 5 67 8 9 10 11 12 1314 15 16 17 18 19 2021 22 23 24 25 26 2728 29 30
September 2008
S E PTE M B E R 2008Sunday Monday Tuesday Wednesday Thursday Friday Saturday
1 2 3 4 5 6
7 8 9 10 11 12 13
14 15 16 17 18 19 20
21 22 23 24 25 26 27
28 29 30
Notes:
© 2007 Vertex42 LLC http ://w w w .vertex42.com
S M T W Th F Sa1 2
3 4 5 6 7 8 910 11 12 13 14 15 1617 18 19 20 21 22 2324 25 26 27 28 29 3031
August 2008S M T W Th F Sa
1 2 3 45 6 7 8 9 10 1112 13 14 15 16 17 1819 20 21 22 23 24 2526 27 28 29 30 31
October 2008
Monday, April 10, 2023
12
Jungfraujoch Field Trial
• NPL FTIR (1.8 tonne of equipment!) transported to Jungfraujoch research station (~3500m above sea level)
• FAAM plane based in Basel
Jungfraujoch research station
(NPL FTIR)
JungfrauMönch
Eiger
FAAM in Basel
Monday, April 10, 2023
13
FAAM Flights• Used glacier on approach for
uniform surface temperature and emissivity measurements
• Runs at 15,000 to 35,000 feet• Spiral ascents over the
Jungfrau• Dropsondes from a high level
Monday, April 10, 2023
14
Jungfraujoch Research Station
• NPL FTIR & MICROTOPS installed at research station. Solar tracker mounted on balcony to face south looking down valley
• Other data available from the station– Liege FTIR (part of NDACC)
– LIDAR (unfortunately v.little coincidence with flights)
– Sonde launches from Payerne
– GPS water vapour
Monday, April 10, 2023
15
Example Effect of High Altitude
• Camborne and Jungfraujoch spectra from NPL FTIR show effect of measuring from high altitude
8000 8200 8400 8600 8800 9000 9200 9400 9600 9800
0
0.05
0.1
0.15
0.2
0.25
Wavenumber / cm-1
FT
IR r
espo
nse
/ a.u
.
CamborneJungfraujoch
Monday, April 10, 2023
16
Jungfraujoch Flights
• 9 flights, compared to 3 in Camborne, justified spending the summer out of Britain!• Sonde launch from Payerne on evening of 20th Jul
– Will allow for comparison against FAAM instruments
• MetOp overpass on morning of 27th Jul• Dates when there was the most coincident air- and ground-based measurements with
the smallest amount of cloud interruption were– 19th, 26th, 27th Jul and 4th Aug – Analysis initially to focus on 27th July as measurement conditions very good (i.e. very clear) and
coincides with MetOp overpass
J U L Y 2009Sunday Monday Tuesday Wednesday Thursday Friday Saturday
1 2 3 4
5 6 7 8 9 10 11
12 13 14 15 16 17 18
19 20 21 22 23 24 25
26 27 28 29 30 31
Notes:
© 2007 Vertex42 LLC http ://w w w .vertex42.com
S M T W Th F Sa1 2 3 4 5 6
7 8 9 10 11 12 1314 15 16 17 18 19 2021 22 23 24 25 26 2728 29 30
J une 2009S M T W Th F Sa
12 3 4 5 6 7 89 10 11 12 13 14 1516 17 18 19 20 21 2223 24 25 26 27 28 2930 31
August 2009
AU G U S T 2009Sunday Monday Tuesday Wednesday Thursday Friday Saturday
1
2 3 4 5 6 7 8
9 10 11 12 13 14 15
16 17 18 19 20 21 22
23 24 25 26 27 28 29
30 31 Notes:
© 2007 Vertex42 LLC http ://w w w .vertex42.com
S M T W Th F Sa1 2 3 4
5 6 7 8 9 10 1112 13 14 15 16 17 1819 20 21 22 23 24 2526 27 28 29 30 31
J uly 2009S M T W Th F Sa
1 2 3 4 56 7 8 9 10 11 1213 14 15 16 17 18 1920 21 22 23 24 25 2627 28 29 30
September 2009
= aborted flight
= successful flight
Monday, April 10, 2023
17
Summary
• Achieved traceable, radiometric calibration of TAFTS, ARIES and NPL FTIR– Custom built CAVIAR BB will be available for future
calibrations
• Two successful field trials at a low and high altitude sites– Bad weather days in Camborne off-set with better than
expected weather in Jungfruajoch. So overall we posses a large body of data
– Have identified key days from each field trial for focussed analysis
• Instrument intercomparison• In support of modelling work
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