1. 3rd Workshop of the International Precipitation Working Group (IPWG) Melbourne, Australia, 23-27/10/2006 10-day forecasts for Melbourne, initialized on Tuesday 12 UTC Cloud Cover Precipitation Wind Speed Temperature Melbourne, UKMelbourne, AustraliaMelbourne, Tennessee

2. 3rd Workshop of the International Precipitation Working Group (IPWG) Melbourne, Australia, 23-27/10/2006 Impact of Rainfall Observations in ECMWF 4D-Var Data Assimilation System Peter Bauer, Philippe Lopez, Alan Geer, and Deborah Salmond European Centre for Medium-Range Weather Forecasts (ECMWF ) Shinfield Park, Reading, Berkshire, RG2 9AX, UK peter.bauer@ecmwf.int

3. 3rd Workshop of the International Precipitation Working Group (IPWG) Melbourne, Australia, 23-27/10/2006 (1D+) 4D-Var Assimilation FG state, error Moist physics-RT model y(x b.i ), F x b, B Satellite data y o, E yJyJ xixi Adjoint: Moist physics-RT model State update x a, A AN state forwardinverse xJxJ

4. 3rd Workshop of the International Precipitation Working Group (IPWG) Melbourne, Australia, 23-27/10/2006 (Courtesy G. Kelly) Typhoon Matsa (04/08/2005 00 UTC) Used SSM/I Clear-sky Channel 3 (22 GHz) Used SSM/I 1D-Var (GMS IR, DMSP F13-15) Thin cirrus Low-level stratus

5. 3rd Workshop of the International Precipitation Working Group (IPWG) Melbourne, Australia, 23-27/10/2006 Typhoon Matsa (04/08/2005 00 UTC) TCWV FG-Departures (GMS IR, DMSP F13-15) (Courtesy G. Kelly) Model too dry Model too moist

6. 3rd Workshop of the International Precipitation Working Group (IPWG) Melbourne, Australia, 23-27/10/2006 MTSAT Infrared image of typhoon MATSA approaching Taiwanese and Chinese coast on August 4, 2005, 00 UTC. Typhoon Matsa (04/08/2005 00 UTC) 4D-Var moisture increments with rain assimilation (colors in %), 900 hPa wind increments (white arrows), surface pressure (isolines).

7. 3rd Workshop of the International Precipitation Working Group (IPWG) Melbourne, Australia, 23-27/10/2006 Mean TCWV Analysis/Forecast Difference 08-10/2004 Rain – No Rain Analysis Day 2 (48h) Day 3 (72h) Day 5 (120h) [kg m -2 ] Global operational systems: ECMWF

8. 3rd Workshop of the International Precipitation Working Group (IPWG) Melbourne, Australia, 23-27/10/2006 Mean MSLP Analysis Difference 08-10/2004 Rain – No Rain Rain Assimilation produces larger MSLP than control Rain Assimilation produces lower MSLP than control [hPa] Global operational systems: ECMWF

9. 3rd Workshop of the International Precipitation Working Group (IPWG) Melbourne, Australia, 23-27/10/2006 Mean 850 hPa Divergent Wind Analysis Difference 08-10/2004 Rain – No Rain Convergence Divergence Global operational systems: ECMWF

10. 3rd Workshop of the International Precipitation Working Group (IPWG) Melbourne, Australia, 23-27/10/2006 90% Statistical significance Improvement Deterioration Mean Relative Humidity Forecast RMSE Difference 08-10/2004 Rain – No Rain Global operational systems: ECMWF

11. 3rd Workshop of the International Precipitation Working Group (IPWG) Melbourne, Australia, 23-27/10/2006 MSLP TCWV Meteosat VIS channel imagery A B Case studies: South Atlantic 12Z, 14/08/2005

12. 3rd Workshop of the International Precipitation Working Group (IPWG) Melbourne, Australia, 23-27/10/2006 TCWV [kg m -2 ] Tb departure [K] SSMI channel 19v19h22v37v37h85v85h FG24.4-8.1-13.6-6.5-15.730.0-7.8-20.6 analysis23.5-0.60.3 -1.9-2.0-2.6-5.7 Analysis First guess 3D model dewpoint temperature Case A: Stratiform Precipitation, high TCWV Rain/snowCloud water/iceCloud cover

13. 3rd Workshop of the International Precipitation Working Group (IPWG) Melbourne, Australia, 23-27/10/2006 Analysis First guess TCWV [kg m -2 ] Tb departure [K] SSMI channel 19v19h22v37v37h85v85h FG7.64.57.92.04.28.84.112.0 analysis8.82.01.3-1.13.4-1.813.35.5 3D model Case B: Convective Precipitation, low TCWV dewpoint temperature Rain/snowCloud water/iceCloud cover

14. 3rd Workshop of the International Precipitation Working Group (IPWG) Melbourne, Australia, 23-27/10/2006 CY30R2/CY31R1: Decrease in tropical Forecast Skill August 2005 24-hour forecast normalized RMS-error difference: Temperature

15. 3rd Workshop of the International Precipitation Working Group (IPWG) Melbourne, Australia, 23-27/10/2006 Rain FG-Departures CY30R2/CY31R1: Moisture Analysis Rain – No Rain AN-Differences unbiased net drying Rain FG-DeparturesAN-Differences Example: 1 st cycle ITCZ East Pacific: Mean August 2004 TCWV difference:

16. 3rd Workshop of the International Precipitation Working Group (IPWG) Melbourne, Australia, 23-27/10/2006 TCWV increments 1-cycle: 2005080100 1D+4D-Var Assimilation system (operational since June 2005) Direct 4D-Var Assimilation system (experimental) [kg m -2 ]

17. 3rd Workshop of the International Precipitation Working Group (IPWG) Melbourne, Australia, 23-27/10/2006 Assimilation over Land: NCEP Stage IV rain accumulations Observations: Combined hourly rain-gauge and NEXRAD radar precipitation accumulation. ~1200 observations over continental US per 12-hour cycle. Available in near real-time incl. quality indicators. Assimilation experiments: T511L60, CY29R2, 20/05-20/06 2005;1D+4D-Var, 1D-Var uses only moist physics in observation operator. Add Stage IV observations to operational data set:  RMSE Z1000 N.AMER (21 cases, own ana)  RMSE Z200 N.ATL (21 cases, own ana) Global experimental systems: ECMWF

18. 3rd Workshop of the International Precipitation Working Group (IPWG) Melbourne, Australia, 23-27/10/2006 noqUS – control noqUS+StageIV – noqUS Mean differences of TCWV analyses at 00UTC 4D-Var Data Denial Experiment control: all observations (incl. SSM/I rain assimilation over oceans); ExperimentsnoqUS: withdraw TEMP-q, RH2m, HIRS, AMSU-B, SSM/I, AIRS, GOES-WV over US; noqUS+StageIV: as noqUS but add Stage IV data. Global experimental systems: ECMWF

19. 3rd Workshop of the International Precipitation Working Group (IPWG) Melbourne, Australia, 23-27/10/2006 Assimilation over Land: TRMM 2A12 Rain Rates Mean TCWV analysis increments 1-25/07/2006 at 00UTC Global experimental systems: ECMWF

20. 3rd Workshop of the International Precipitation Working Group (IPWG) Melbourne, Australia, 23-27/10/2006  RR 24h TCWV RR 24h  TCWV 24-hour Forecast Differences: Rain – No Rain Rain Rain - No Rain Global experimental systems: ECMWF

21. 3rd Workshop of the International Precipitation Working Group (IPWG) Melbourne, Australia, 23-27/10/2006 Analysis system: General: 1 st global operational 4D-Var system (since June 2005)! Introduces first satellite observations in cloud/rain affected areas. Incremental 4D-Var efficient and well behaved. Summary Observations: - Radiance measurements provide sensitivity in both clear and cloudy conditions (compared to rain rate observations). - Microwave radiances very accurately measured, stable calibration, continuous availability from operational satellites. - Combined microphysics + microwave radiative transfer operator well behaved and not too non-linear. Errors: - Observation + modelling errors can only be indirectly derived (but realistic). - Background errors require improved specification inside clouds/precipitation. Control variable: - Desirable: Control variable that includes water vapour and condensates. 1D+4D-Var: Advantage:- additional quality control, - safe first implementation, Disadvantage: - background fields are used twice, - only moisture increments provided to 4D-Var, - loss of vertical information, - only instantaneous measurements are assimilated.

22. 3rd Workshop of the International Precipitation Working Group (IPWG) Melbourne, Australia, 23-27/10/2006 Future Employ 1D+4D-Var system with microwave sounder/imager observations over land surfaces. Fully implement direct 4D-Var radiance assimilation system: - make use of quality control lessons learned from 1D+4D-Var system. - allow variable use of different imager/sounder channel combinations as in clear-sky applications. - extend to infra-red observations from space. Requires: - Background error formulation that is more cloud/precipitation specific. - Developments towards total water control variable. - Continuous efforts towards improved moist physics parameterizations. Combined efforts of physics/data assimilation/satellite sections at ECMWF Programmatic involvement: - Global Precipitation Measuring (GPM) mission, NASA & JAXA, 2013+. - Post-EPS programme, Eumetsat, 2020+. - Earth Explorer programme, ESA, uncertain. - WMO International Precipitation Working Group (IPWG).

23. 3rd Workshop of the International Precipitation Working Group (IPWG) Melbourne, Australia, 23-27/10/2006 ocean land AMSR-E+ Rain Snow Eumetsat Polar System (EPS) follow-on, 2020+ Study on dedicated specifications for clouds and precipitation: channel selection Channel identification and hydrometeor retrieval accuracy estimation (also with AMSR-E as baseline) (Channel priorities for land/ocean surfaces, global profile datasets, optimal estimation theory, x-axis: mean entropy reduction) Definition of passive microwave imager specs for post-EPS

24. 3rd Workshop of the International Precipitation Working Group (IPWG) Melbourne, Australia, 23-27/10/2006 Publications Andersson, E., P. Bauer, A. Beljaars, F. Chevallier, E. Hólm, M. Janisková, P. Kallberg, G. Kelly, P. Lopez, A. McNally, E. Moreau, A. Simmons and J.-N. Thépaut, 2005: Assimilation and Modelling of the Hydrological Cycle. Bull. Amer. Meteor. Soc., 86, 387-402. Andersson, E., E. Hólm, P. Bauer, A. Beljaars, G.A. Kelly, A.P. McNally, A.J. Simmons, and J.-N. Thépaut, 2006: Analysis and forecast impact of the main humidity observing system. Q. J. Roy. Meteor. Soc., submitted. Bauer, P., J.-F. Mahfouf, S. di Michele, F.S. Marzano, W.S. Olson, 2002: Errors in TMI rainfall estimates over ocean for variational data assimilation. Q. J. Roy. Meteor. Soc., 128, 2129-2144. Bauer, P., E. Moreau, F. Chevallier, and U. O'Keefe, 2006: Multiple-scattering microwave radiative transfer for data assimilation applications. Q. J. Roy. Meteor. Soc., 132, 1259-1281. Bauer, P., P. Lopez, A. Benedetti, D. Salmond, and E. Moreau, 2006: Implementation of 1D+4D-Var assimilation of precipitation affected microwave radiances at ECMWF, Part I: 1D-Var. Q. J. Roy. Meteor. Soc., in press. Bauer, P., P. Lopez, A. Benedetti, D. Salmond, S. Saarinen and M. Bonazzola, 2006: Implementation of 1D+4D-Var assimilation of precipitation affected microwave radiances at ECMWF, Part II: 4D-Var. Q. J. Roy. Meteor. Soc., in press. Benedetti, A., P. Lopez, P. Bauer, and E. Moreau, 2005: Experimental use of TRMM Precipitation Radar observations in 1D+4D-Var assimilation. Q. J. Roy. Meteor. Soc., 131, 2473-2495. Benedetti, A., P. Lopez, E. Moreau, P. Bauer and V. Venugopal. 2005: Verification of TMI-Adjusted Rainfall Analyses of Tropical Cyclones at ECMWF Using TRMM Precipitation Radar. J. Appl. Meteor., 44, 1677-1690. Chevallier, F., P. Bauer, J.-F. Mahfouf, and J.-J. Morcrette, 2002: Variational retrieval of cloud profiles from ATOVS observations., Q. J. Roy. Meteor. Soc., 128, 2511-2525. Chevallier, F. and P. Bauer, 2003: Model rain and clouds over oceans: Comparison with SSM/I observations. Mon. Wea. Rev., 131, 1240-1255. Errico, R., P. Bauer, and J.-F. Mahfouf, 2006: Assimilation of cloud and precipitation data: Current issues and future prospects. J. Atmos. Sci., submitted. Lopez, P., and E. Moreau, 2005: A convection scheme for data assimilation: Description and initial tests. Q. J. Roy. Meteor. Soc., 131, 409--436. Lopez, P., A. Benedetti, P. Bauer, M. Janisková, M. and M. Köhler, 2006: Experimental 2D-Var assimilation of ARM cloud and precipitation observations, Q. J. Roy. Meteor. Soc., 132, 1325-1347. Mahfouf, J.-F., P. Bauer, and V. Marécal, 2003: The comparative impact of the assimilation of SSM/I and TMI rainfall rates in the ECMWF 4D-Var system, Q. J. Roy. Meteor. Soc., 131, 437-458. Marécal V. and J.-F. Mahfouf, 2000: Variational retrieval of temperature and humidity profiles from TRMM precipitation data. Mon. Wea. Rev., 128, 3853-3866. Marécal, V., J.-F. Mahfouf, and P. Bauer, 2002: Comparison of TMI rainfall estimates and their impact on four-dimensional variational rainfall assimilation. Q. J. Roy. Meteor. Soc., 128, 2737-2758. Marécal V. and J.-F. Mahfouf, 2002: Four-dimensional variational assimilation of total column water vapour in rainy areas. Mon. Wea. Rev., 130, 43- 58. Marécal V. and J.-F. Mahfouf, 2003: Experiments on 4D-Var assimilation of rainfall data using an incremental formulation. Quart. J. Roy. Meteor. Soc., 129, 3137-3160 Moreau, E., P. Bauer, and F. Chevallier, 2002: Variational retrieval of rain profiles from spaceborne passive microwave radiance observations. J. Geophys. Res., 203, D16, 4521, doi: 10.1029/2002JD003315, ACL11-1-ACL11-18. Moreau, E., P. Lopez, P. Bauer, A. Tompkins, M. Janisková, and F. Chevallier, 2003: Rainfall vs. microwave brightness temperature assimilation: A comparison of 1D-Var results using TMI and SSM/I observations. Q. J. Roy. Meteor. Soc., 130, 827-852. O'Dell, C.W., P. Bauer, and R. Bennartz, 2006: A fast cloud overlap parameterization for microwave radiance assimilation. J. Atmos. Sci., submitted.