The ESA DUE GlobVapour water vapour products

1. The ESA DUE GlobVapour water vapour products Marc Schröder on behalf of the GlobVapour consortium Deutscher Wetterdienst, Offenbach, Germany AGU Fall Meeting San Francisco, USA, 17 December 2010

2. Outline • The project • Water vapour products with focus on SSM/I+MERIS • Validation • First application • Conclusions AGU Fall Meeting San Francisco, USA, 17 December 2010

3. Objectives • Development of multi-annual global water vapour data sets inclusive error estimates based on carefully calibrated and intercalibrated radiances. • Validation of the water vapour products against ground based, in-situ and other satellite based measurements. • Provision of a complete processing system that can further strengthen operational production of the developed products. • Demonstration of the usage of the products in the field of climate modelling, also applying alternative ways of climate model validation using forward radiation operators. AGU Fall Meeting San Francisco, USA, 17 December 2010

4. Consortium From left to right: M. Stengel, T. Steenbergen, B. Bojkov, R. Lindstrot, M. Grzgorski, J. Fischer, M. Schroeder, J. Schulz, T. Wagner, N. Schneider, R. Leinweber, R. Preusker Not on the photo: D. Loyola, S. Slijkhuis, A. Doicu, R. Saunders, M. Ringer, H. Gleisner, U. Kraemer, M. Goldberg AGU Fall Meeting San Francisco, USA, 17 December 2010

5. Product overview • Total column water vapour, three data sets: • Combined SSM/I (above ocean) and MERIS (above land) for 2003 – 2008 with composite and monthly products; daylight product. • GOME/SCIA/GOME-2 above ocean and land for 1996 – 2008 with weekly and monthly resolution; daylight product. • (A)ATSR-2 ocean for 1996 – 2008 in daily and monthly resolution, all day. • Water vapour profiles, one data set: • Merged IASI+SEVIRI, SEVIRI full disk; three vertical layers (surf. - 850 hPa, 850 hPa – 500 hPa, 500 hPa - 200 hPa); October 2007 – December 2008, all day. • Technical features: • Geographical maps in lat/lon representation. • netcdf applying the Climate and Forecast metadata standard. • Data sets include uncertainty measures, number of observations on grid basis, cloud mask, …. AGU Fall Meeting San Francisco, USA, 17 December 2010

6. Timeline Dec 2009 Start of project Mar 2010 Requirements and technical specifications review Nov 2010 Prototype products, ATBD, Validation Report (4 month in 2006-2008) Mar 2011 User Workshop I, jointly with GEWEX Radiation Panel Meeting Jun 2011 Test products (2006-2008) Sep 2011 User Workshop II Nov 2011 Final products (1996-2008) Nov 2011 End of project AGU Fall Meeting San Francisco, USA, 17 December 2010

7. Validation • Radiosondes • G(R)UAN • Specific campaigns • GPS data • E-GVAP • SoumiNet • GSD • Microwave radiometers • ARM • MOL • Lidar data • NDACC • MOL • Aircraft data • Mozaic • Other satellite products • GRAS, COSMIC, CHAMP • MODIS • AIRS • ATOVS • HIRS • Utilisation of: • Common metric applied to all products. • Inter-comparison among GlobVapour products. AGU Fall Meeting San Francisco, USA, 17 December 2010

8. Interim results: GOME/SCIAMACHY/GOME-2 Principle: DOAS and measured air mass factor (Wagner et al. 2003) and homogenisation in product space following (Loyola et al., 2009). Features: Global; dx=0.5°; dt=weekly, monthly; day only. GOME2, March 2007, max=60 kg/m2 See talk of Thomas Wagner today at 12:10 AGU Fall Meeting San Francisco, USA, 17 December 2010

9. SSM/I retrieval Principle: 1D-VAR using RTTOV, both from NWP-SAF. Recalibration, homogenisation for microwave observations from SSM/I from CM SAF. ERA-Int 1D-Var RGB uncertainty AGU Fall Meeting San Francisco, USA, 17 December 2010

10. SSM/I retrieval Optimum between retrieval quality and independency from a-priori information is analysed. MWR from Nauru ARM site AGU Fall Meeting San Francisco, USA, 17 December 2010

11. MERIS retrieval Principle: New development with the main objective to provide pixel based retrieval uncertanties: Single scattering approximation, Forward model for ratio of reflectances at 885 and 900 nm, Secant method to find optimal solution. AGU Fall Meeting San Francisco, USA, 17 December 2010

12. MERIS retrieval Principle (continued): At coastal regions the MERIS product is also produced but has decreased quality. However, quality could be significantly improved through improved handling of atmospheric scattering under low reflectance conditions. Relatively stable radiances >2003 for MERIS. AGU Fall Meeting San Francisco, USA, 17 December 2010

13. Combination of SSM/I + MERISbias consideration • Bias consideration: • Retrieve TCWV from MERIS in sunglint. • Bias determined/provided but not applied. Zoom into sun glint regions (08/2007) AGU Fall Meeting San Francisco, USA, 17 December 2010

14. Combination of SSM/I + MERISTechnical specification and updated result • Combined product: • Day only; dt=composites, monthly • MERIS above land + coast (dx=0.05°); SSM/I above ocean (dx=0.5°) AGU Fall Meeting San Francisco, USA, 17 December 2010 Monthly average for July 2007

15. Combination of SSM/I + MERISUpdated results Complementary information utilised. Individual advantages conserved, in particular, uncertainty estimates remain valid. Daily composite for 03 July 2007 AGU Fall Meeting San Francisco, USA, 17 December 2010

16. Validationbias of SSM/I+MERIS Red GUAN Yellow AIRS Blue MODIS NIR (TERRA, AQUA) Green MODIS IR (TERRA, AQUA) Orange ATOVS See talk of Theo Steenbergen today at 17:50 AGU Fall Meeting San Francisco, USA, 17 December 2010

17. Application Comparison of GlobVapour TCWV to ERA-Interim and HadGEM2 AGU Fall Meeting San Francisco, USA, 17 December 2010

18. More GlobVapour • Total column water vapour: - AATSR as input to sea surface temperature retrievals. - Microwave radiometer (MWR) on ENVISAT to serve sea level height retrievals. • Water vapour profiles: - Merged SEVIRI+IASI observations: utilise high temporal and high vertical resolution. - IASI water vapour profile assessment. See talk of Bruno Picard, CLS, today at 12:30 See talk of Martin Stengel today at 17:20 AGU Fall Meeting San Francisco, USA, 17 December 2010

19. Newsletter • Second volume of the GlobVapour Newsletter released. • Inform on progress, events and products. • Release: half-yearly. • Content: • Introduction. • Combined SSM/I+MERIS product. • GOME-like products. • Validation. • First application: Comparison to climate model and reanalysis. • Project consortium. AGU Fall Meeting San Francisco, USA, 17 December 2010

20. Webpage www.globvapour.info General Information Breaking News Downloads: Newsletter Products Documentation (Requirements User Guide Validation Reports) AGU Fall Meeting San Francisco, USA, 17 December 2010

21. Conclusions • First products can be downloaded and ordered. • Products in netCDF following CF standard, with full error information and on easy to handle grid. • Close link to and feedback from User Group to improve products and usability. • Join IASI assessement and/or User Group. • Specials thanks to: Jörg Schulz, EUMETSAT; Katja Hungershöfer, DWD; Marc Schwärz, Uni. Graz; Bojan Bojkov, ESA; NWP-SAF, NWC-SAF… www.globvapour.info AGU Fall Meeting San Francisco, USA, 17 December 2010