Research Article

Frontiers of Earth Science

, Volume 7, Issue 2, pp 217-226

First online:

A novel solution for outlier removal of ICESat altimetry data: a case study in the Yili watershed, China

  • Xiaodong HuangAffiliated withState Key Laboratory of Grassland Agro-ecology System, College of Pastoral Agriculture Science and Technology, Lanzhou University
  • , Hongjie XieAffiliated withLaboratory for Remote Sensing and Geoinformatics, Department of Geological Sciences, University of Texas at San Antonio Email author 
  • , Guoqing ZhangAffiliated withKey Laboratory of Tibetan Environment Changes and Land Surface Processes, Institute of Tibetan Plateau Research, Chinese Academy of Sciences
  • , Tiangang LiangAffiliated withState Key Laboratory of Grassland Agro-ecology System, College of Pastoral Agriculture Science and Technology, Lanzhou University

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Abstract

Due to the influence of cloud and saturated waveforms, ICESat data contain many contaminated elevation data that cannot be directly used in examining surface elevation and change. This study provides a novel solution for removing bad data and getting clean ICESat data for land applications by using threshold values of reflectivity, saturation, and gain directly from ICESat’s GLAS (Geoscience Laser Alteimeter System) 01, 05, and 06 products. It is found that each laser campaign needs different threshold compositions to assure qualified ICESat data and that bad data removal rates range from 9.6% (laser 2A) to 62.3% (laser 2B) for the test area in the Yili watershed, China. These thresholds would possibly be used in other regions to extract qualified ICESat footprints for land applications. However, it is recommended to use the steps proposed here to further examine the transferability of threshold values for other regions of different elevations and climate regimes. As an example, the resulting ICESat data are applied to examine lake level changes of two lakes in the study area.

Keywords

ICESat outliers and removal Yili watershed lake level