SAR衛星による高頻度観測結果を用いた鹿島灘南部の汀線変動解析  [in Japanese] STUDY ON SHORELINE VARIABILITIES OF SOUTHERN KASHIMANADA COAST ANALYZED FROM FREQUENTLY OBSERVED SAR DATA  [in Japanese]

Access this Article

Search this Article

Author(s)

Abstract

合成開口レーダ(Synthetic Aperture Radar)衛星はマイクロ波レーダを搭載した衛星であり,雲天時,夜間にも観測可能である.そのため光学(可視)衛星に比べ同一地点のシーンを高頻度に取得できる.年に複数回取得されたシーンより汀線位置を読み取り,漂砂系内の季節的な汀線変動を追跡した.高頻度に観測されたデータの解析結果を示し,その優位性を検討する.具体的には地球観測衛星ALOS (PALSAR)(運用期間:2006~2011年)とALOS-2 (PALSAR-2)(2014年~現在)が取得した鹿島灘南部(鹿島港~利根川河口)の32シーンを分析した.2006年から2016年にかけての約10年間の汀線変動の特徴を議論し,年に1回取得される観測結からは抽出できない汀線変動特性を説明する.

 Variation of shoreline positions of 16 km-long sandy Kashima Coast, a littoral cell, with Kashima Port at the north end and Hasaki Fishery Port at the southern end, has been observed from SAR (Synthetic Aperture Radar) satellite. Since SAR is able to observe data in day and night times, and cloudy weather conditions, it can frequently collect scenes than optical satellites. In this study, 32 scenes from year 2006 to 2016 observed by ALOS / PALSAR (operated by JAXA, 2006 - 2011), and ALOS-2 / PALSAR-2 (JAXA, 2014 to present) is analyzed to trace long-term and seasonal variations. First, bulk statistics of shoreline position variations are discussed. The variation of overall mean shows some seasonal fluctuation, however, it has no trend meaning the coast is almost stable during the period. Then, EOF (Empirical Orthogonal Function) analysis is applied to separate the variation into several major modes. First mode looks to represent variation of simultaneous and seasonal movements of the shoreline position due to cross-shore sediment, and the second mode due to long-shore sediment. EOF analysis is also done with partial data set, one scene per year, to compare the result with full data set analysis. As a result, we got similar modes for spatial functions of EOF modes, however, temporal functions were quite different. This is showing the frequent acquisition of data is essential to understand the details of shoreline variabilities in a littoral cell, especially the seasonal.

Journal

  • Journal of Japan Society of Civil Engineers, Ser. B2 (Coastal Engineering)

    Journal of Japan Society of Civil Engineers, Ser. B2 (Coastal Engineering) 74(2), I_985-I_990, 2018

    Japan Society of Civil Engineers

Codes

  • NII Article ID (NAID)
    130007504095
  • Text Lang
    JPN
  • Article Type
    journal article
  • ISSN
    1884-2399
  • NDL Article ID
    029326859
  • NDL Call No.
    YH267-236
  • Data Source
    NDL  IR  J-STAGE 
Page Top