1. 1 Ozone Profile Retrieval from SBUV/2 Sweep Mode Data---Preliminary Results Xiong Liu, Kelly Chance Harvard-Smithsonian Center for Astrophysics Matthew Deland Science Systems and Applications, Inc. Pawan K. Bhartia Atmospheric Chemistry and Dynamics Branch, NASA GSFC

2. 2 Outline n Brief Introduction to Retrieval Algorithm n Examples of Retrievals n Intercomparison with SAGE-II and TOMS n Retrieval Characterization (averaging kernels, DFS) n Future Work

3. 3 Algorithm Description n Optimal estimation: regularized with TOMS V8 climatology and photon random-noise error n Test Data: NOAA-16, 5 June 2001, 4 orbits, 64 spectra n Fitting window: 262-340 nm (spatial resolution ~166  334 km 2 ) n Slit width: determined with NLLS, triangular, ~1.1 nm FWHM n Wavelength calibration: NLLS n Forward model: LIDORT model + first-order RRS n Cloud: cloud-top pressure (ISCCP), varying cloud fraction n Surface albedo: wavelength-independent ( 308 nm) n 12 layers (equal-log pressure, ~5 km ): partial column O 3 (DU) n Other variables in state vector: Ring effect(1), Surface albedo(4), NO2(2),SO2(2), radiance-irradiance shift(4), O3-radiance shift(4)

4. 4 Random-Noise Error and Fitting Window NOAA-16 SBUV/2 06/05/01 4 orbits 64 pixels 262-340 nm 166  334 km 2

5. 5 An Example of Retrieval North Africa (43.1E, 10.1N)

6. 6 Comparison with SAGE-II SBUV TO3=274 DU EPTOMS TO3=276 DU SBUV TO3=276 DU EPTOMS TO3=276 DU Scale A Priori by 120%

7. 7 Comparison with EP-TOMS Total Ozone SBUV-TOMS 2.9±11.1 DU R = 0.98

8. 8 Retrieval Averaging Kernels SZA=29, DFS=5.4, TROPDFS=0.95 VR:7-9km(30-50km),12-17km(5-30km) SZA=78.6, DFS=6.5, TROPDFS=0.70 VR:6-8km (30-60km), 8-11 km(10-30km)

9. 9 Degrees of Freedom for Signals DFS below 125 mb: 0.9 DFS above 125 mb: 4.9 Total DFS: 5.8

10. 10 Future Work n Optimize retrievals and fitting window: may need to remove some spectral regions below 290 nm that are greatly affected by strong Fraunhofer lines and NO-  bands n More validation against SAGE-II/HALOE & TOMS n Apply this algorithm to other nadir-viewing UV measurements