1. DMU Arctic polar plots P.A.M. Berry and R.G. Smith
You owe us some drinks, especially Richard who plotted all of these whilst preparing for his Ph.D. defence!

2. Introduction
This ppt contains polar plots of the waveform distribution for different echo types for three cycles: A031 (30 March 1995 start), A036 ( 21 September 1995 start), A041 (15 March 1996 start) of ERS2.
These cycles have been fully processed, so the ocean retracker (9) is the full Brown model fit, and all waveforms that conform to this model have been retracked with the Brown model.
The first plots show the Brown model waveform spatial distribution

3. A031 retracker 9
Percentage of total echoes
Brown model waveforms: note sea-ice around Greenland progressively diminishing successful Brown model retracking towards coast: temporal averaging a factor

4. A036 retracker 9
Percentage of total echoes
Far higher proportion of Brown model echoes in summer, again grading down into the sea-ice

5. A041 retracker 9
Percentage of total echoes
Some structure apparent where tiny percentage of echoes are still passing a Brown model fit away from open ocean

6. Retracker 7
The next slides show complex echo shapes from composite surfaces; expect ice/water combination.

7. A031 retracker 7 Significant occurrence in this cycle.
Percentage of total echoes
Significant occurrence in this cycle.

8. A036 retracker 7
Percentage of total echoes

9. A041 retracker 7
Percentage of total echoes

10. A031 retracker 10 Very bright, very thin quasi-specular echoes
Percentage of total echoes: note that some echoes occur at >40% for retracker 10 plots, these appear as red
Very bright, very thin quasi-specular echoes
Note increased occurrence at ice edge, very still pools of water, also melt pools on ice

11. A036 retracker 10 Very high occurrence at ice edge and melt pools
Percentage of total echoes: note that some echoes occur at >40% for retracker 10 plots, these appear as red
Very high occurrence at ice edge and melt pools

12. A041 retracker 10 Structure apparent in echo occurrence over ice
Percentage of total echoes: note that some echoes occur at >40% for retracker 10 plots, these appear as red
Structure apparent in echo occurrence over ice

13. Next slides show retracker 11
Next slides show retracker 11. Extremely complex echoes from composite surfaces with diverse components: profoundly non-uniform surface.

14. A031 retracker 11
Percentage of total echoes
Wealth of detailed spatial information from this echo type

15. A036 retracker 11
Percentage of total echoes
Much smaller area in summer exhibiting these characteristics, as expected. Storm conditions can cause a few echoes over ocean to trigger this retracker: hence ‘stripes’ of ocean dots from 3 day sub-cycle

16. A041 retracker 11
Percentage of total echoes
Structure evident

17. A031 retracker 8
Percentage of total echoes
Very calm ocean triggers this retracker, also snow on ice can return a similar echo shape.

18. A036 retracker 8
Percentage of total echoes
Calm ocean

19. A041 retracker 8
Percentage of total echoes