1. 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

2. 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

3. (Courtesy of Lee et al., 2005）

4. 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

5. Regularization Inversion
Equations
Unknowns
Solutions
Newton Iteration
Discrepancy Principle (Li and Huang 1999)

6. Discrepancy Principleγ
Residual = Observation error

8. 394 AIRS Channels
1688 AIRS Channels

10. Sept.6, 2002, G193
1km MODIS Cloud Mask

11. Against
ECMWF

12. 500 hPa T difference
500 hPa q (g/kg) difference

13. 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)

17. 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

18. 1DVAR algorithm for cloud retrieval
Fast Cloudy Radiative Transfer Model: coupled
Observed AIRS Radiance Measurements
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
Background Information from MODIS
Minimum Residual (MR) algorithm for cloud retrieval

20. MODIS Cloud Phase
( Courtesy of Chianyi LIU)

21. AIRS CTH (m)
Barrow

25. 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

26. 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.