1. Waveform Analysis of Envisat RA-2 data We have pre-processed 9 days’ of data from Envisat and piped them through the expert system. Summary: –Data over land are in ocean mode only. This limits the scope of our analysis and degrades data quality –S band and Ku band waveform shapes are generally as expected and appear valid. S band waveforms show more difference from Ku than C band, as expected, but topographic component is largely still dominant –Global statistics have been calculated for each 15 degree square, relative performances are shown on next page (left side) as percentages of valid waveforms. Comparison 55%-100% ranges forced on each dataset are shown on right side for intercomparison. Cycle 62 of ERS-2 has been used for comparison.

2. Envisat and ERS-2 statistics Envisat % valid waveforms (freescale)Envisat % valid waveforms forced 55-100% ERS-2 Cycle 62 valid waveforms (freescale)ERS-2 valid waveforms forced 55-100%

3. Conclusions Global statistics show an anomalously poor performance of Envisat RA-2 over the Amazon and Congo river basins. (More detail has been presented in the report). Most rejected waveforms are due to no leading edge being present in the data. Generally over land in ocean mode, RA-2 performance appears similar to Topex Ku band. Significant loss of data is evident. Mode switching must occur over land if potential of Envisat RA-2 is to be realised. Performance over rivers is anomalously and seriously degraded compared to ERS-1/2 ice and ocean modes, Topex Ku and Topex C band data. This is a serious problem. More data are required to make a comprehensive analysis and assess other river networks. We require at least one full cycle of data with returns in all three modes to assess performance as required by our Cal/Val terms of reference.