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Overview of Camborne field campaignStuart Newman

Imperial College, 16 December 2008

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CAVIAR field campaign #1Overview of Camborne campaign

CAVIAR work package 3.3 Campaign centred on Camborne (Cornwall), 13 August to 25 September 2008

Site provides measurements of meteorological variables and radiosonde balloon profiles of temperature and water vapour

FAAM aircraft flew in conjunction with measurements of NPL’s high resolution solar-tracking FTS on the ground

As a coastal site can exploit downward pointing interferometer measurements from the FAAM aircraft over the sea (homogeneous surface emission) as well as upward pointing measurements

Campaign #2 (Jungfraujoch Swiss Alps scientific station, Sept 2009) will be complementary with ≈ tenth column water vapour c.f. Camborne

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FAAM BAe 146-301 capability

Blister containing ARIES and TAFTS

ARIES interferometer (Bomem MR200)Spectral range 550-3000 cm-1

TAFTS interferometer (Imperial College)Spectral range 80-800 cm-1

Both instruments view upwelling and downwelling radiances

• Dropsondes

• Core chemistry (ozone and CO)

• Temperature and humidity probes

• Multi-spectral radiometer (solar)

• Microwave radiometers

• Particulates (aerosols and cloud particles)

• Winds (and more…)

Endurance 5½ hoursAltitude 20 m – 10.5 km

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Camborne radiosonde station

• NPL solar-tracking FTS based on site

• Regular radiosonde ascents (midday) plus extra ascents on request

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Observations versus simulationsMethodology for Camborne field campaign

NPL solar-tracking FTS at CamborneSurface temperature and emissivity from

runs at low level

Intensive profiling

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Summary of flights

• British “summer” weather in August and September not always conducive to clear sky conditions!

• Flights conducted on five separate days

• One day (22/8) included a double flight with refuel

• Two flights were aborted due to excessive cloud

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Ground-based data

• NPL solar-tracking Fourier transform spectra

• Radiosonde balloons

• GPS integrated water vapour

• Lidar backscatter

• Microwave T, q retrievals

• MICROTOPS sun photometer

6:00 8:00 10:00 12:00 14:00 16:00 18:00

U.T. / hh:mm

12/08/2008

13/08/2008

19/08/2008

22/08/2008

18/09/2008

23/09/2008

24/09/2008

Dat

e / d

d:m

m:y

yyy

CAV33: Duration of NPL Camborne Ground Based Measurements

Volume of Reading University Mircotops Data

0

10

20

30

40

50

60

07/23/2008 08/07/2008 08/12/2008 08/13/2008 08/19/2008 08/22/2008 09/18/2008 09/23/2008

Date / dd/mm/yyyy

Num

ber o

f Mea

surm

ents

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Campaign data cont.

• Met Office and ECMWF analyses (model fields)

• MetOp satellite data

• Aircraft instrument data

• See http://badc.nerc.ac.uk/data/caviar/

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B396 flight (19 Aug 2008)

• Persistent boundary layer cloud over Camborne, with some clear sky breaks

• 10 dropsondes released

• 12 aircraft runs over Camborne at different altitudes

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B397 flight (22 Aug 2008)

• Occasional broken boundary layer cloud over Camborne, with good clear sky breaks

• Double flight with refuel

• 17 dropsondes released

• 22 aircraft runs over Camborne at different altitudes

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B400 flight (18 Sep 2008)

• Very good clear sky conditions

• Flight included “chase” of radiosonde for water vapour intercomparison

• 6 dropsondes released

• 8 aircraft runs over Camborne at different altitudes

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B400 flight (18 Sep 2008)

• Best clear sky conditions encountered – no need for cloud hole hunting

• ARIES and TAFTS seemed to operate well

• Reasonably stable atmospheric structure

• High aerosol loading but IR measurements insensitive to this

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ARIES data from 3 altitudes

residual differences (obs-calc) / K

ARIES nadir brightness temperatures

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TAFTS summary

Date Flight no. Meteorology Useful science

TAFTS performance

13/08/08 B394 N/A Test flight

19/08/08 B396 Persistent broken StCu, increasing late on

Yes Partial laser up to 1.5hrs

22/08/08 B397/398 Some broken StCu Yes No laser

11/09/08 B399 Too cloudy (Aborted) Good

18/09/08 B400 Excellent Yes Excellent

23/09/08 B404 Too cloudy (Aborted) Good

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TAFTS example data Comparison with simulation

Upwelling

Downwelling

Local OAT

Simulation (both UW

and DW)

Ch0

Ch1

Run 4, 34kft (7mins of data) against dropsonde #3

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NPL solar-tracking FTS High resolution spectra at IR/solar wavelengths

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Summary and future work

• Three successful flights were completed over Camborne in Summer 2008

• Comprehensive data set combining radiance observations and measurements of the atmospheric state

• Ongoing work to derive best estimates for temperature and water vapour profiles for case studies

• Aircraft interferometer data quality looks good for B400

• Future work: corroborate results by comparing with other flight days, and intercompare results from ARIES, TAFTS and NPL FTS

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Questions and answers

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North South

ARIES retrieval (B400)

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B400 case for initial analysis

FL340 (250 hPa)

FL290 (314 hPa)

FL145 (583 hPa)