Development of a filtering solution for outliers in satellite altimetry-derived significant wave heights in the East Sea

Abstract

The objective of this study is to develop a solution for filtering out significant wave height values that do not meet accuracy requirements from satellite altimetry data in the East Sea. Satellite altimeters typically operate with two frequency bands (e.g., Ku and C), both of which can be used to derive significant significant wave heights. By comparing significant wave heights obtained from these two bands, anomalous values that deviate from statistical probability distributions can be identified. At these anomalous points, the Ku-band–derived significant wave heights are further compared with neighboring values to determine whether they should be discarded or retained. To automate the filtering process, a computer program was developed. The experiment was conducted over the East Sea using 464,324 measurements from 226 cycles of Jason-3 satellite data collected between February 12, 2016, and March 28, 2022. A detailed analysis of cycle 225 revealed 28 anomalous points, of which 6 were removed. For the entire Jason-3 dataset, 460 measurements (approximately 0.1%) were discarded. Although the number of rejected points is small, their removal is necessary. The accuracy of the significant wave heights, evaluated by comparing Ku- and Cband results from Jason-3, was found to be ±0.254 m.