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AIRS Sounding and Cloud Property Study. Xuebao Wu, Jun Li, Paul Menzel,Allen Huang In collaboration with CIMSS colleagues National Satellite Meteorology Center, Beijing, China CIMSS, University of Wisconsin-Madison, Madison, U.S.A. Mar.6, 2006. Outline. ( Clear Sounding Study)
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AIRS Sounding and Cloud Property Study Xuebao Wu, Jun Li, Paul Menzel,Allen Huang In collaboration with CIMSS colleagues National Satellite Meteorology Center, Beijing, China CIMSS, University of Wisconsin-Madison, Madison, U.S.A. Mar.6, 2006
Outline ( Clear Sounding Study) 1. Algorithm---Regression&Physical 2. Two Experiments 3. Validation (Cloud Property Study) 4. MR Retrieval Method 5. Case Study: MPACE 6. Validation
Part 1. Clear IR Sounding Retrieval Regression Physical retrieval (regularization) which needs --Radiance measurements and observation errors --First guess from regression or other sources --Fast Radiative Transfer Model -- Others
Regularization Inversion Equations Unknowns Solutions Newton Iteration Discrepancy Principle (Li and Huang 1999)
Discrepancy Principle γ Residual = Observation error
394 AIRS Channels 1688 AIRS Channels
Sept.6, 2002, G193 1km MODIS Cloud Mask
Against ECMWF
500 hPa T difference 500 hPa q (g/kg) difference
Validation with match up dataset • Match up dataset at ARM SGP Site AIRS/Best Estimate (Sept. of July 2002 – Aug. of 2004) ) • Use AIRS retrieval algorithm developed at CIMSS (regression + physical)
Part 2 Cloud Property Study Some features: • Minimum Residual Retrieval Method • Ping Yang’s fast cloud RT model • MODIS cloud mask and cloud phase to characterize the AIRS SFOV
1DVAR algorithm for cloud retrieval Observed AIRS Radiance Measurements Background Information from MODIS Fast Cloudy Radiative Transfer Model: coupled CTP: Cloud-Top Pressure; ECA: Effective Cloud Amount CPS: Cloud Particle Size; COT: Cloud Optical Thickness at 0.55µm CTP and ECA: 720 – 790 cm**-1 COT and CPS: 790 – 1130 cm**-1 Minimum Residual (MR) algorithm for cloud retrieval
MODIS Cloud Phase ( Courtesy of Chianyi LIU)
AIRS CTH (m) Barrow
Conclusion? • Clear sky sounding retrieval algorithm has been tested using AIRS data. Physical retrieval work reliably. One day MPACE study. • Ongoing works and Remaining issues(Esfc,BiasCorr) • Acknowledge: HalW, KevinB, JinglongL,SeeBor, DaveT
Reference: Wu Xuebao, Li Jun, Zhang Wenjian, and Wang Fang, Atmospheric Profile Retrieval with AIRS Data and Validation at the ARM CART Site, Advances in Atmospheric Sciences, 2005, Vol. 22, No. 5, 647–654. Wu, X., J. Li, W. P. Menzel, A. Huang, K. Baggett, and H. Revercomb, Evaluation of AIRS cloud properties using MPACE data, Geophys. Res. Lett., 2005, 32, L24819.