1. 00/XXXX1 RTTOV-7: A satellite radiance simulator for the new millennium What is RTTOV Latest developments from RTTOV-6 to 7 Validation results for RTTOV-7 How to get it R Saunders, M Matricardi, P Brunel S English and G Deblonde

2. 00/XXXX2 Acknowledgements NWP Satellite Application Facility A Collard, P Rayer, S English, E Carroll/F Smith M Matricardi, F Chevallier, G Kelly, Erik Andersson, D Salmond P Brunel G Deblonde, V Sherlock, T Kleespies EUMETSAT for partial funding

3. 00/XXXX3 Other RTTOV related talks/posters M Matricardi New transmittance predictors/AIRS F Chevallier Diverse profile datasets V Sherlock Gastropod for AIRS simulations T Kleespies Inclusion of OPTRAN in RTTOV

4. 00/XXXX4 Fast Model Approaches (profile  TOA radiances) Linear regression (profile  optical depth) –On fixed pressure levels –On fixed absorber overburden layers (OPTRAN) Physical method Look up tables Neural nets

5. 00/XXXX5 History of RTTOV RTTOV-3 released in 1993 by ECMWF Eyre, (1991) –40 levels mixed gases, 15 levels H 2 O –Based on 32 NESDIS profile dataset and ITPP TOVSRAD RTTOV-5 released in 1999 Saunders et al (1999) –43 levels for mixed gases, H 2 O and O 3. –Based on 43 TIGR profile dataset and GENLN2/MPM- 89/92 –FASTEM RTTOV-6 released in Apr 2000 SAF report RTTOV-7 released Feb 2002 SAF report

6. 00/XXXX6 RTTOV-6 model Statistical regression of layer optical depths with profile variables on fixed pressure levels for mixed gases, water vapour and ozone IR optical depths based on GENLN2, HITRAN- 96/CKD2.1 in range 500 - 3000 cm -1 MW optical depths based on MPM 89/92 Line by Line models 43 diverse TIGR profile dataset used to compute coeffs for model (dependent set)

7. 00/XXXX7 RTTOV-6 model (cont) Includes fast surface emissivity models (ISEM for IR and FASTEM for MW) at least over water, more work needed over land Includes simplistic treatment of cloud Code written in F77 & F90 and available through SAF (RTTOV-6 has > 40 users worldwide including major NWP centres) Variety of different sensors supported (next slide)

8. 00/XXXX8 Recent RTTOV developments Improved water vapour and ozone optical depth predictors (ECMWF) Multi-layer clouds, more realistic emissivities and random overlap assumption have been added for both IR and MW External routines (ECMWF) Update of microwave sea surface emissivity model FASTEM to FASTEM-2 (METO/MSC) Inclusion of cosmic background radiation (MSC) Addition of high spectral resolution sounders (ECMWF) and SSMI(S) (MSC/METO) Code rewritten in standard F90,vectorised and made threadsafe (MeteoFrance/ECMWF) Separate coefficient files for each sensor (MeteoFrance) New web site (METO)

9. 00/XXXX9 Satellite sensors supported by RTTOV-6/7 Italics RTTOV-7 only Sensor Chan #

10. 00/XXXX10 How to validate RTTOV? –Use an independent set of profiles (e.g. ECMWF diverse 117 profile set) but with same LbL model computed transmittances »Gives estimate of inherent model accuracy of trasmittances and TOA radiances –Fast model comparisons (e.g. Garand et al 2001, Gastropod) of radiances and jacobians »Gives performance of model compared to others –Line-by-line model comparisons (e.g. ISSWG LIE) »Gives estimate of underlying LbL model accuracy –Comparisons with real satellite data using NWP fields

11. 00/XXXX11 Validation of AMSU-B transmittances Dashed RTTOV-6; solid RTTOV-7

12. 00/XXXX12 Dependent vs independent statistics HIRS 1-20 AMSU 21-40

13. 00/XXXX13 Validation of radiances HIRS 1-20 AMSU 21-40

14. 00/XXXX14 Validation of jacobians HIRS 1-20 AMSU 21-40

15. 00/XXXX15 Garand fast model intercomparison for HIRS channels RTTOV 5 and 6

16. 00/XXXX16 SSMI(S) Filters

17. 00/XXXX17 SSMIS brightness temps

18. 00/XXXX18 Validation of jacobians

19. 00/XXXX19 NWP O-B scan angle stats RTTOV-5 RTTOV-7

20. 00/XXXX20 Validation of HBH T RTTOV-5 RTTOV-7 Model background error as HIRS-12 radiance

21. 00/XXXX21 New water vapour spectroscopy Using Toth revision of the water vapour spectroscopy, resulted in a better agreement between observations and simulations

22. 00/XXXX22 RTTOV-7 now available with improved water vapour and ozone simulation for both IR and MW channels Smoother jacobians better assimilation More realistic cloudy radiances can be computed using RTTOVCLD routines Improved simulation of MW surface emissivity AIRS/SSMIS/FY radiance simulation included Summary

23. 00/XXXX23 Future plans  RTTOV-8 Improve interface with NWP model levels Update LbL dependent transmittances with latest spectroscopy Optimise predictors (number, robustness) Improve fast land surface emissivity models and extend range of ISEM-6 Add solar reflection Include precipitation in state vector for microwave Add more variable gases (e.g. CH 4, N 2 O, CO 2 ) Add IASI simulation capability

24. 00/XXXX24 RTTOV-7 Distribution http://www.metoffice.com/research/interproj/nwpsaf/rtm/ Requests: email rttov.nwpsaf@metoffice.com or fax request to me on +44-1344-854026 I will reply with a 2 page licence form to sign which you then fax to number above RTTOV-7 code is then distributed via ECMWF data services: data.services@ecmwf.int on requested format/medium Two formats: »Compressed unix tar file of F90 code+files »CDROM of F90 code+files Media: ftp transfer or CDROM Documentation + updates available from NWP-SAF web page above. RTTOV-6 is also available (e.g. for F77 users) Please give feedback on any bugs by email to: rttov.nwpsaf@metoffice.com

25. 00/XXXX25 RTTOV-7 Documentation/Updates http://www.metoffice.com/research/interproj/nwpsaf/rtm/ Users guide (overview, installation, testing, interfaces) Science and validation plan (overview of new science and links to papers/reports giving more details, validation results documented here). Technical report (details of software architecture, file formats and interfaces) SAF reports on RTTOV (access from web page) Bugs and fixes (alerts on RTTOV email list, details on web page)