Analysis of EnviSat Altimetric Data around Yangtze Estuary by Waveform Retracking

doi:10.11947/j.AGCS.2015.20140374

Abstract

Abstract: The waveform data of EnviSat satellite (28°N~32°N, 121°E~125°E) from October 2002 to May 2010 is processed by waveform retracking methodology based on waveform classification. The waveforms in this region are classified into ocean, pre-peak, post-peak, quasi-specular and complex waveforms, with percentages of 89.03%, 2.95%, 0.45%, 3.31% and 4.26%, respectively. For each waveform, correspondent waveform retracking methodology is used. Meanwhile, it is founded that there exist system biases between the sea surface heights(SSH) calculated by different waveform retracking methodologies and calculate optimum threshold level of OCOG, threshold and sub-waveform retracker, with 65%, 45% and 50% respectively. The results of waveform retracking show that the waveform retracking methodology based on waveform classification are prior to any single retracker, which could improve the precision of SSH from 16.62% to 53.86%. In addition, the crossover discrepancies are smaller after using waveform retracking. Specifically, the crossover discrepancies of pass 089 and pass 411 are declined from 1 m to 25 cm or so and the other crossover discrepancies are all around 2~6 cm.

Key words: satellite altimetry, waveform classification, cluster analysis, waveform retracking

CLC Number:

P228

PENG Fukai, SHEN Yunzhong. Analysis of EnviSat Altimetric Data around Yangtze Estuary by Waveform Retracking[J]. Acta Geodaetica et Cartographica Sinica, 2015, 44(6): 616-624.

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