© Crown copyright Met Office Initial assessment of ARIES continuum measurements Stuart Newman Imperial College, 16 December 2008.

© Crown copyright Met Office

Initial assessment of ARIES continuum measurementsStuart Newman

Imperial College, 16 December 2008

© Crown copyright Met Office

B400 flight (18 Sept 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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Preliminary data analysis

FL340 (250 hPa)

FL290 (314 hPa)

FL145 (583 hPa)

• Select only nadir views over ocean to north of Camborne

• Use dropsonde profile launched from FL340 in line-by-line simulations

• SST from low level (100 ft) ARIES data

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Longwave IR (self continuum)

spread ~ 0.6K

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SST variability

Northern data segment used in simulations

>1K

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Strong water vapour band

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Continuum MT_CKD too strong?

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North South

ARIES retrieval (B400)

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Summary and future work

• Preliminary analysis of ARIES nadir data over ocean (zenith data may be subject to calibration biases)

• B400 case: small brightness temperature biases in (self continuum dominated) longwave window; larger biases in (foreign broadened) strong midwave band

• Future work: estimate uncertainties in atmospheric profiles and ARIES radiances

• Include collocated IASI radiances from MetOp overpass in data analysis

• Corroborate results by comparing with other flight days

• Intercompare results from ARIES, TAFTS and NPL FTS

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Questions and answers