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GlobVapour, Workshop 08-10 March 2011 Status of the operational IASI L2 products Thomas August (EUMETSAT) Tim Hultberg, Dorothée Coppens, Arlindo Arriaga,

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Presentation on theme: "GlobVapour, Workshop 08-10 March 2011 Status of the operational IASI L2 products Thomas August (EUMETSAT) Tim Hultberg, Dorothée Coppens, Arlindo Arriaga,"— Presentation transcript:

1 GlobVapour, Workshop March 2011 Status of the operational IASI L2 products Thomas August (EUMETSAT) Tim Hultberg, Dorothée Coppens, Arlindo Arriaga, Lars Fiedler, Xavier Calbet, Dieter Klaes, Peter Schlüssel, Rose Munro, Marc Crapeau Status of the operational IASI L2 version 5 products Slide: 1

2 GlobVapour, Workshop March 2011 Status of the operational IASI L2 products Slide: 2 Outline I.Overview of the IASI mission II.The IASI L2 processor (PPF) version 5 III.Discussion on T, q validation IV.Summary

3 GlobVapour, Workshop March 2011 Status of the operational IASI L2 products Slide: 3 I. The IASI mission The instrument CO CH 4 O3O3 H2OH2O CO 2 N2ON2O Surface Clouds Surface Clouds T profiles Infrared Fourier transform interferometer Spectral range: 645 to 2760 cm -1 ( µm) Spectral sampling: 0.25 cm -1 Footprint: 12 km (Nadir) Swath: ±1000km (± 48.3°)

4 GlobVapour, Workshop March 2011 Status of the operational IASI L2 products I. The IASI mission Metop and the EPS program Slide: 4  Prime objective: provide continuous, long-term data sets in support of operational meteorological and environmental forecasting and global climate monitoring.  Lifetime: 3 satellites, more than 14 years operation from October  Imager (AVHRR) and MW (AMSU,MHS) companions  European contribution to The Initial Joint Polar-orbiting System (IJPS)  Satellites in complementary orbits designed to ensure global data coverage at intervals of no more than 6 hours.

5 GlobVapour, Workshop March 2011 Status of the operational IASI L2 products Slide: 5 Vertical profiles: Temperature Vertical profiles: Humidity Land & Sea Surface Temperature Cloud detection and characterisation Ozone: total & partial (0-6, 0-12, 0-16 km) columns CO N 2 O CH 4 CO 2 Total columns Surface emissivity TWT EMS CLD OZO TRG I. The IASI mission The operational L2 products Disseminated in NRT (sensing +3h) Slide: 5

6 GlobVapour, Workshop March 2011 Status of the operational IASI L2 products II. IASI L2 PPF version 5 Why upgrade ? Slide: 6 bias σ Processing chain version 5 operational since 14 September 2010 ! rmse σ bias v4 v5 IASI – 500 hPa Error [K]

7 GlobVapour, Workshop March 2011 Status of the operational IASI L2 products 1.Input data pre-processing 2.Cloud detection and characterisation 3.Statistical retrievals: T, q, Ts, ε, trace gases 4.Optimal Estimation Method (OEM): T, q, Ts, O 3 Slide: 7 Conf. data Static db IASI L1C NWP Aux. meas. IASI L2 product EOF cloudy EOF ANN cloud-free OEM II. IASI L2 PPF version 5 The main steps

8 GlobVapour, Workshop March 2011 Status of the operational IASI L2 products Data typeOriginResolution Land/Sea maskAAPPquadtree Surface elevation GTOPO 30 (US Geological Survey) 30” x 30” (~1 km) Emissivity Atlas Global land surface IR emissivity database UW-Madison (Borbas et al., 2007) 0.05° x 0.05° lat/lon 10 wavelengths Monthly means Emissivity Atlas Global land surface climatology from IASI measurements (Zhou et al., submitted to IEEE TGRS ) 0.5°x0.5° Full spectrum (via PCs) Monthly means Slide: 8 II. IASI L2 PPF version 5 The static databases

9 GlobVapour, Workshop March 2011 Status of the operational IASI L2 products  IASI L1C radiances Noise-filtering via PC reconstruction  ECMWF 6h-forecasts: 00, 06, 12, 18 UTC Up to 3h difference with sensing-time Time-interpolation  AVHRR L1B used if IASI L1C format < 11.0 Cloud-fraction embedded in IASI 1C used for cloud screening  AMSU & MHS 1B Not used yet. “Potential for the use of reconstructed IASI radiances in the detection of atmospheric trace gases”, N. C. Atkinson, F. I. Hilton, S. M. Illingworth, J. R. Eyre, and T. Hultberg, AMT 2010 Raw L1C Ammonia Reconstructed Slide: 9 II. IASI L2 PPF version 5 Measurements & aux. products

10 GlobVapour, Workshop March 2011 Status of the operational IASI L2 products II. IASI L2 PPF version 5 Cloud detection  NWP cloud test OBS – CALC(NWP, ems, … chans 751 & 1023 Cloudy if |OBS-CALC| > 1K Relies on accurate forecasts and surface ems  AVHRR integrated cloud-fraction IASI PSF weighted count of AVHRR cloudy pixels Cloudy if CFR > 2%  Cloud optical depth test EOF retrieval, D. Zhou et al., GRL 2005 Triggers final acceptance of cloudy retrievals Slide: 10 NWP testAVHRR testOpt. depth test 18/11/2009 White: clear

11 GlobVapour, Workshop March 2011 Status of the operational IASI L2 products II. IASI L2 PPF version 5 Statistical retrievals: T, q profiles  EOF retrieval (D. Zhou et al., 2005, GRL)  Regression with different coefficients for different viewing angles  Full profiles available under clear and partly cloudy conditions  Clear sky: first-guess in the final iterative retrieval  Clear sky: q profiles enters final L2 products  Cloudy IFOVs: after users request, the cloudy T,q profiles retrievals were added to the final IASI L2 products. Distributed since 02/12/2010. Slide: 11

12 GlobVapour, Workshop March 2011 Status of the operational IASI L2 products II. IASI L2 PPF version 5 Statistical retrievals: SST NWP cloud test ANN cloud test No dust - ANN cloud test Slide: 12 AVHRR cloud test Impact of the cloud & aerosol detection on the product quality (AATSR – IASI) SST Global figures Cold bias: 0.4 K σ ~ 0.4 K Outside aerosol areas Cold bias: 0.25 K σ < 0.3 K IASI L2P GHRSST Global figures Cold bias: 0.4 K σ ~ 0.4 K Outside aerosol areas Cold bias: 0.25 K σ < 0.3 K IASI L2P GHRSST

13 GlobVapour, Workshop March 2011 Status of the operational IASI L2 products II. IASI L2 PPF version 5 Statistical retrievals: LST Slide : K -10 Bias 5 K 0 σ March 2010 :: Night LANDSAF_MSG – IASI Global figures (excluding deserts) ρ ~ 0.99 Warm bias ~ 1 K σ < 2 K Global figures (excluding deserts) ρ ~ 0.99 Warm bias ~ 1 K σ < 2 K Slide: 13

14 GlobVapour, Workshop March 2011 Status of the operational IASI L2 products II. IASI L2 PPF version 5 The iterative retrieval: OEM  Standard Optimal Estimation Method (OEM) after Rodgers: J = (x - x a ) T. B -1. (x - x a ) + (F(x) – y) T. R -1. (F(x) – y) Marquardt-Levenberg minimisation (5 iterations max.)  Active parameters: T skin and T, q & O 3 profiles  Background term computed in the EOF space of the atmospheric parameters: T -> 28 PCs, q -> 18 PCs, O 3 -> 9 PCs  One unique global a priori and covariance matrix  316 channels after Collard (Collard et al., QJRMS 2007)  global radiance tuning and measurement error covariance matrix: prior clear sky OBS-CALC  Forward model: RTIASI-4 optimised for faster computations  First guess: statistical retrievals Slide: 14

15 GlobVapour, Workshop March 2011 Status of the operational IASI L2 products II. IASI L2 PPF version 5 T, q profiles: non-regression check Slide: 15 Non-regression check and validation result from comparisons against ECMWF analyses. 3 datasets: -“One Year” orbits centred on analyses synoptic times -“Focus days” (8 Sep 2007, 5 March and 9 May 2008) March 2010, with latest L1c products Detailed results presented in EUM/MET/TEN/09/0448

16 GlobVapour, Workshop March 2011 Status of the operational IASI L2 products II. IASI L2 PPF version 5 T, q profiles: non-regression check Slide: 16 Ps < 900 hPa

17 GlobVapour, Workshop March 2011 Status of the operational IASI L2 products II. IASI L2 PPF version 5 Temp. profiles: non-regression check Slide: 17 - v5 - v4 rms ~ 0.7 K !!! March 2010 IASI - ECMWF Yield increased x1.7 rms ≤ 1K [ hPa]

18 GlobVapour, Workshop March 2011 Status of the operational IASI L2 products II. IASI L2 PPF version 5 WV profiles: non-regression check EOF FG March 2010 (IASI - ECMWF) Bias reduced in BDL Slide: 18 OEM - v5 - v4

19 GlobVapour, Workshop March 2011 Status of the operational IASI L2 products  Include covariance T skin – T – WV and possibly O 3 in BG  Synergistic use of MW measurements: AMSU, MHS  Add physical constraints (super-saturation and adabiatic lapse rate) to restrict solution space  More channels needed for humidity retrievals: external study for MTG-IRS by C. Serio (Univ. Basilicata), paper by Rodgers in Adv. Space Res  Migration to RTTOV-10: Upgraded spectroscopy MW instruments => residual cloud contamination effect PCRTM => use more channels in retrievals Simulation of clouds & aerosols All channels 300 PCs 300 channels Credits: C.Serio (Univ. Basilicata) II. IASI L2 PPF version 5 OEM: Future developements Slide: 19

20 GlobVapour, Workshop March 2011 Status of the operational IASI L2 products III. Discussion on T,q validation NOAA/NPROVS Slide: 20 IASI L2 PPFv hPa PPFv4PPFv5 Credits: NOAA / NESDIS Center for Satellite Applications and Research. AIRS AQUA COSMIC UCAR IASI NOAA IASI EUM

21 GlobVapour, Workshop March 2011 Status of the operational IASI L2 products III. Discussion on T,q validation NOAA/NPROVS Slide: 21 PPFv hPa Credits: NOAA / NESDIS Center for Satellite Applications and Research. AIRS AQUA COSMIC UCAR IASI NOAA IASI EUM

22 GlobVapour, Workshop March 2011 Status of the operational IASI L2 products III. Discussion on T,q validation Sodankylä Slide: 22 Humidity profiles: High variability, model vs sondes differences Credits: X. Calbet (EUM) and R. Kivi (FMI) 13/07/2007 Calbet et al., AMTD σ noise

23 GlobVapour, Workshop March 2011 Status of the operational IASI L2 products  3 main field experiments during Austral springs 2008, 2009 and 2010  In 2010, 19 super-pressure balloons (CNES) launched from McMurdo, 6 with a scientific payload sounding the stratosphere, and 13 of the driftsonde type developed at NCAR.  From the 13 driftsondes flying at around 20km altitude, ~640 dropsondes were dropped over Antarctica and the surrounding seas, coincident with Metop overpasses.  Additional measurements performed at other stations in Antarctica: Dumont d’Urville, Concordia and Rothera.  Drop-ondes coincident with Metop and A-Train overpasses IASI/AVHRR CMF Credits: Lydie Lavanant CALIOP CTP (hPa) IASI EUM III. Discussion on T,q validation ConcordIasi Co-operation with F. Rabier and L. Lavanant (Meteo-France) Slide: 23

24 GlobVapour, Workshop March 2011 Status of the operational IASI L2 products Summary Slide: 24 PPFv5 operational since 14/09/2010 ! Significant improvements: T, LST, clouds (O3, CO) Products further characterised: SST, LST Some cloudy retrievals Validation documentation available on-line:  Improve/characterise further T and q in bottom layers  Reduce use of NWP forecasts ¿Seasonal variations in long-term monitoring: origins ? How to account for it in CDRs ? ¿clouds/aerosol detection/simulation impact on WV profiles quality ? ¿What WV products references for the validation of satellite retrieved profiles with ground resolution of km ?

25 GlobVapour, Workshop March 2011 Status of the operational IASI L2 products Thank you for your attention ! Slide: 25


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