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Microwave Emissivity Model Upgrade for New Instruments

Microwave Emissivity Model Upgrade for New Instruments. Fuzhong Weng NOAA/NESDIS/Office of Research and Applications. Banghua Yan QSS Group Inc. Kozo Okamoto EMC Visiting Scientist, now at JMA. The 3 rd JCSDA Science Workshop, April 20-21, 2005, Camp Springs, MD.

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Microwave Emissivity Model Upgrade for New Instruments

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  1. Microwave Emissivity Model Upgrade for New Instruments Fuzhong Weng NOAA/NESDIS/Office of Research and Applications Banghua Yan QSS Group Inc Kozo Okamoto EMC Visiting Scientist, now at JMA The 3rd JCSDA Science Workshop, April 20-21, 2005, Camp Springs, MD

  2. JCSDA Road Map (2002 - 2010) By 2010, a numerical weather prediction community will be empowered to effectively assimilate increasing amounts of advanced satellite observations The radiances can be assimilated under all conditions with the state-of-the science NWP models Resources: NPOESS sensors ( CMIS, ATMS…) GOES-R OK Deficiency The CRTM includes scattering & polarization from cloud, precip and surface Advanced JCSDA community-based radiative transfer model, Advanced data thinning techniques The radiances from advanced sounders will be used. Cloudy radiances will be tested under rain-free atmospheres, and more products (ozone, water vapor winds) are assimilated AIRS, ATMS, CrIS, VIIRS, IASI, SSM/IS, AMSR, more products assimilated Science Advance A beta version of JCSDA community-based radiative transfer model (CRTM) transfer model will be developed, including non-raining clouds, snow and sea ice surface conditions Improved JCSDA data assimilation science The radiances of satellite sounding channels were assimilated into EMC global model under only clear atmospheric conditions. Some satellite surface products (SST, GVI and snow cover, wind) were used in EMC models AMSU, HIRS, SSM/I, Quikscat, AVHRR, TMI, GOES assimilated Pre-JCSDA data assimilation science Radiative transfer model, OPTRAN, ocean microwave emissivity, microwave land emissivity model, and GFS data assimilation system were developed 2002 2003 2008 2009 2010 2004 2005 2007

  3. JCSDA Community Radiative Transfer Model Atmospheric State Vectors Surface State Vectors Atmospheric Spectroscopy Model Surface Emissivity, Reflectivity Models Aerosol and Cloud Optical Model Forward Radiative Transfer Schemes Receiver and Antenna Transfer Functions Jacobian (Adjoint) Model

  4. Surface Emissivity Model Natural Scenes Theory Base Two-Scale Approx. Geometric Optics Scattering/ observations Scattering/ observations

  5. Surface Emissivity • Open water – two-scale roughness theory • Sea ice – Coherent reflection • Canopy – Four layer clustering scattering • Bare soil – Coherent reflection and surface roughness • Snow/desert – Random media Weng et al (2001, JGR)

  6. Deficiencies of Snow Modeling • Not applicable for aged snow • Limited at frequencies less than 50 GHz • Not applicable for vertically stratified snow • Two stream radiative transfer approach

  7. Table 1. Brightness Temperature Sensitivity to Surface Emissivity  = 0.04

  8. Advanced Microwave Sounding UnitSounding Channels 52.8 GHz 53.7 GHz 183+-3 GHz 183+-1 GHz

  9. Snow Emissivity Data Base Emissivity Retrieval: AMSU-A: 23.8, 31.4, 50.3, 89 GHz AMSU-B: 89, 150 GHz AVHRR: Ts RAOBS temperature/q profiles Winter season of 2003: Eastern part of US: persistent snow cover during February

  10. Snow Storms (February 2003)

  11. Dry snow >12 in Heavy rain Refrozen New snow

  12. Snow Emissivity Spectra 23.8 31.4 50.3 89 150

  13. Sea Ice Emissivity Spectra Sea ice types: see Hewison and English, IEEE, 1999

  14. Impacts of Surface Emissivity Operational

  15. Impacts of Surface Emissivity Experimental

  16. Impacts of Surface Emissivity Experimental - Operational

  17. Impacts of AMSU on Forecasts in Polar Region Anomaly Correlation for 700 hPa Geopotential Height

  18. Snow Microwave Emissivity Spectra

  19. Sea Ice Microwave Emissivity Spectra

  20. H-POL (SST = 300 K) V-POL (SST = 300 K) Ocean H-POL Emissivity Ocean V-POL Emissivity V-POL (SST =280 K) H-POL (SST = 280 K) Ocean V-POL Emissivity Ocean H-POL Emissivity Performance of Ocean Emissivity Model in GDAS

  21. Comparison between Met Office and NESDIS Ocean Emissivity Models ►NESDIS Ocean Emissivity Model (Hollinger, 1971; Stogryn, 1972; Klein and Swift, 1977 ) ►Met Office Ocean Emissivity Model (A semi-empirical model, English and Hewison)

  22. Histogram of Simulated TB Bias at AMSR-E Channels Using Met Office Ocean Emissivity Model

  23. Histogram of Simulated TB Bias at AMSR-E Channels Using NESDIS Ocean Emissivity Model

  24. Summary of Accomplishments • Microwave emissivity models have been updated for new sensors (SSMIS, MHS) over snow and sea ice conditions • Microwave snow and sea ice emissivity models are integrated as part of CRTM • These upgrades improve AMSU data utilization rate in polar atmospheres (200-300% increase). • Impacts of the emissivity models on global 6-7 forecasts are also assessed and significant

  25. Outstanding Issues • Ocean microwave emissivity model used in NCEP global data assimilation system is found to cause larger biases in simulated brightness temperatures at lower frequencies, compared to the model developed by NESDIS, especially at high wind speeds

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