1. CORRECTION OF SPATIAL ERRORS IN SMOS BRIGHTNESS TEMPERATURE IMAGES L. Wu, I. Corbella, F. Torres, N. Duffo, M. Martín-Neira

5. Basics on mask estimation over the ocean Geometry (faraday) rotation Polynomial regression Geometry (faraday) rotation The final mask is computed on antenna frame.

10. Final Mask on antenna frame Mask is computed using several orbits over the pacific ocean from 20 th ,Feb to 20 th ,Sep, 2010.

11. Cuts of the mask X pol Y pol The spatial error is constrained to ±2% in SMOS AF-FoV

12. Mask average along track Mask average along track is not zero mean producing artifacts along this direction.

13. Images over the Indian ocean (01/12) applying the mask

14. Residual Spatial errors Radiometric spatial errors (pixel bias) over ocean The mask clearly reduces the residual error and randomizes its spatial distribution. case Error budget v7.0 2.13 2.13 Before mask correction 1.34 1.57 After mask correction 0.38 0.47

15. Corrected brightness temperature H/V brightness temperature arranged for equal incidence angle for a SMOS image over the Atlantic Ocean and the Indian Ocean, before (top) and after (bottom) applying the mask correction.

16. Effect on Level 1C brightness temperature Horizontal polarization Vertical polarization (35º to 55º incidence)

17. Image cut at -25º latitude

18. Mask stability check (i) single mask deviation from mean mask computed in March, May and July 2010 to show temporal stability.

19. Mask stability check (ii) the masks computed using ascending orbits' data are more stable than using descending orbits'.