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GlobVapour, Workshop 08-10 March 2011 Status of the operational IASI L2 products Thomas August (EUMETSAT) Tim Hultberg, Dorothe Coppens, Arlindo Arriaga, Lars Fiedler, Xavier Calbet, Dieter Klaes, Peter Schlssel, Rose Munro, Marc Crapeau Status of the operational IASI L2 version 5 products Slide: 1 Slide 2 GlobVapour, Workshop 08-10 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 Slide 3 GlobVapour, Workshop 08-10 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 (15.5-3.62 m) Spectral sampling: 0.25 cm -1 Footprint: 12 km (Nadir) Swath: 1000km ( 48.3) Slide 4 GlobVapour, Workshop 08-10 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 2006. 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. Slide 5 GlobVapour, Workshop 08-10 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 Slide 6 GlobVapour, Workshop 08-10 March 2011 Status of the operational IASI L2 products II. IASI L2 PPF version 5 Why upgrade ? Slide: 6 bias Processing chain version 5 operational since 14 September 2010 ! rmse bias v4 v5 IASI ECMWF @ 500 hPa 0 1 2 Error [K] Slide 7 GlobVapour, Workshop 08-10 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, , 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 Slide 8 GlobVapour, Workshop 08-10 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 ) 0.5x0.5 Full spectrum (via PCs) Monthly means Slide: 8 II. IASI L2 PPF version 5 The static databases Slide 9 GlobVapour, Workshop 08-10 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 Slide 10 GlobVapour, Workshop 08-10 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 Slide 11 GlobVapour, Workshop 08-10 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 Slide 12 GlobVapour, Workshop 08-10 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 ~ 0.4 K Outside aerosol areas Cold bias: 0.25 K < 0.3 K IASI L2P GHRSST Global figures Cold bias: 0.4 K ~ 0.4 K Outside aerosol areas Cold bias: 0.25 K < 0.3 K IASI L2P GHRSST Slide 13 GlobVapour, Workshop 08-10 March 2011 Status of the operational IASI L2 products II. IASI L2 PPF version 5 Statistical retrievals: LST Slide : 13 10 K -10 Bias 5 K 0 19-24 March 2010 :: Night LANDSAF_MSG IASI Global figures (excluding deserts) ~ 0.99 Warm bias ~ 1 K < 2 K Global figures (excluding deserts) ~ 0.99 Warm bias ~ 1 K < 2 K Slide: 13 Slide 14 GlobVapour, Workshop 08-10 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 Slide 15 GlobVapour, Workshop 08-10 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) -19-24 March 2010, with latest L1c products Detailed results presented in EUM/MET/TEN/09/0448 Slide 16 GlobVapour, Workshop 08-10 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 Slide 17 GlobVapour, Workshop 08-10 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 !!! 19-24 March 2010 IASI - ECMWF Yield increased x1.7 rms 1K [200-800hPa] Slide 18 GlobVapour, Workshop 08-10 March 2011 Status of the operational IASI L2 products II. IASI L2 PPF version 5 WV profiles: non-regression check EOF FG 19-24 March 2010 (IASI - ECMWF) Bias reduced in BDL Slide: 18 OEM - v5 - v4 Slide 19 GlobVapour, Workshop 08-10 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. 1998 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 Slide 20 GlobVapour, Workshop 08-10 March 2011 Status of the operational IASI L2 products III. Discussion on T,q validation T @ NOAA/NPROVS Slide: 20 http://www.star.nesdis.noaa.gov/smcd/opdb/poes/NPROVS.php IASI L2 PPFv5.0 T @ 500 hPaT @ 700 hPaT @ 850 hPa PPFv4PPFv5 Credits: NOAA / NESDIS Center for Satellite Applications and Research. AIRS AQUA COSMIC UCAR IASI NOAA IASI EUM Slide 21 GlobVapour, Workshop 08-10 March 2011 Status of the operational IASI L2 products III. Discussion on T,q validation WV @ NOAA/NPROVS Slide: 21 PPFv5 WV @ 500 hPaWV @ 700 hPaWV @ 850 hPa Credits: NOAA / NESDIS Center for Satellite Applications and Research. AIRS AQUA COSMIC UCAR IASI NOAA IASI EUM Slide 22 GlobVapour, Workshop 08-10 March 2011 Status of the operational IASI L2 products III. Discussion on T,q validation Sondes @ Sodankyl 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 2010 3 noise Slide 23 GlobVapour, Workshop 08-10 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 dUrville, Concordia and Rothera. Drop-ondes coincident with Metop and A-Train overpasses IASI/AVHRR CTP @ CMF Credits: Lydie Lavanant CALIOP CTP (hPa) IASI CTP @ EUM III. Discussion on T,q validation ConcordIasi Co-operation with F. Rabier and L. Lavanant (Meteo-France) Slide: 23 Slide 24 GlobVapour, Workshop 08-10 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: www.eumetsat.intwww.eumetsat.int 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 12-30 km ? Slide 25 GlobVapour, Workshop 08-10 March 2011 Status of the operational IASI L2 products Thank you for your attention ! thomas.august@eumetsat.int Slide: 25