Rain and ice flagging of Envisat altimeter and MWR data

• Main Authors: John Lillibridge, Remko Scharroo
• Other Authors: The Pennsylvania State University CiteSeerX Archives
• Format: Text
• Language: English
• Published: 2005
• Subjects: Sea ice
• Online Access: http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.652.2017; http://eprints.soton.ac.uk/17318/1/Salz_final_lillibridge.pdf

Altimetry range, wave height, and wind speed measurements are often corrupted by two effects over the ocean: rain and sea-ice. Radiometer measurements, which provide the altimetric wet troposphere correction, are similarly corrupted by the presence of rain or sea-ice in the instrument's footprint. To avoid contamination of sea surface height measurements, it is imperative that data influenced by either of these effects be edited out. The waveform “peakiness ” parameter, available on the GDR data sets is effective at identifying sea-ice returns when stringent thresholds are applied. The mean relationship between backscatter (0) at the two altimeter frequencies allows one to flag data impacted by both rain and sea-ice. We present here a new method for flagging rain or sea-ice contaminated data, based on two-dimensional histograms of 0. 1.