| 海潮负荷对沿海地区宽幅InSAR形变监测的影响 |
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| 引用本文： | 李鹏,李振洪,冯万鹏,刘睿,黄继锋,丁咚,王厚杰.海潮负荷对沿海地区宽幅InSAR形变监测的影响[J].地球物理学报,2019,62(8):2845-2857. |
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| 作者姓名： | 李鹏 李振洪 冯万鹏 刘睿 黄继锋 丁咚 王厚杰 |
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| 作者单位： | 1. 海底科学与探测技术教育部重点实验室, 中国海洋大学海洋地球科学学院河口海岸带研究所, 青岛 266100;2. 青岛海洋科学与技术国家实验室, 海洋地质过程与环境功能实验室, 青岛 266061;3. 英国纽卡斯尔大学工程学院, 纽卡斯尔NE1 7RU;4. 长安大学地质工程与测绘学院, 西安 710054;5. 广东地球动力学作用与地质灾害重点实验室, 中山大学地球科学与工程学院, 广州 510275;6. 武汉大学测绘学院, 武汉 430079 |
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| 基金项目： | 国家自然科学基金项目（41806108，41606066），国家重点研发计划（2016YFA0600903），山东省自然科学基金项目（ZR2016DB30），中国博士后科学基金面上资助项目（2016M592248），青岛市自主创新计划应用基础研究项目（16-5-1-25-jch），中央高校基本科研业务费专项资金（201713039），青岛市博士后人员应用研究项目资助. |
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| 摘 要： | 海岸带地区是全球自然生态环境最为复杂和脆弱的地域之一，合成孔径雷达干涉测量（InSAR）技术可以为全球人类活动、气候变暖和俯冲带剧烈构造运动等背景下的大范围海岸带地理环境变化研究提供重要观测资料.海洋潮汐导致固体地球长周期形变，波长尺度为102~103 km的海潮负荷引入mm级至cm级的形变梯度，此类非构造信号对海岸带InSAR精密形变分析（如：大范围、微小、缓慢且非稳态构造过程等）造成显著影响.本文以宽幅模式SAR数据为例，基于多种海潮模型研究了全球典型海岸带地区（福建、智利和阿拉斯加湾）海潮负荷效应对宽幅InSAR形变监测的影响，给出了宽幅InSAR海潮负荷三维分量估计与差分相位提取方法，并进一步讨论了基于不同海潮模型估计海潮负荷位移的差异.海潮负荷影响不仅与研究范围大小有关，其形变梯度变化与研究区域地形特征存在强相关，对于长波长形变分析而言，传统平面或者曲面拟合方法难以有效分离海潮负荷位移.
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| 关 键 词： | 海岸带形变监测 海潮负荷位移 合成孔径雷达干涉测量 宽幅模式 海潮模型 |
| 收稿时间： | 2018-12-21 |
Impacts of ocean tidal loading on coastal deformation mapping with wide-swath InSAR observations |
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| LI Peng,LI ZhenHong,FENG WanPeng,LIU Rui,HUANG JiFeng,DING Dong,WANG HouJie.Impacts of ocean tidal loading on coastal deformation mapping with wide-swath InSAR observations[J].Chinese Journal of Geophysics,2019,62(8):2845-2857. |
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| Authors: | LI Peng LI ZhenHong FENG WanPeng LIU Rui HUANG JiFeng DING Dong WANG HouJie |
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| Abstract: | Coastal zone is one of the most complex and fragile natural ecological environments in the world. Synthetic Aperture Radar Interferometry (InSAR) techniques can provide vital information on surface topography and deformation in the ocean-land transition zones under the background of global human activities, climate warming and violent tectonic movements over subduction zones. Ocean tides cause a temporal variation of the ocean mass distribution and the associated load on the crust and produce time-varying deformations of the Earth that can reach 100 mm with a wavelength scale of 102~103 km and deformation gradients of mm level to cm level. This kind of non-tectonic signals will have a significant impact on InSAR precision deformation analysis (e.g.large-scale slow and non-steady tectonic deformation with small magnitude). In this study, we used various ocean tidal models to investigate the ocean tidal load (OTL) effects on wide-swath (WS) mode InSAR (e.g. ALOS-2 PALSAR-2 and Sentinel-1A) deformation monitoring in three typical coastal regions including China, Chile and Gulf of Alaska. We detailedly demonstrated the method of three-dimensional component estimation of OTL and differential OTL phase for WS InSAR and further discussed the differences of ocean tidal models in the estimation of OTL displacements. We find that (1) the magnitude of the OTL effects relates with the spatial range of the study regions, and (2) there are strong correlations between the OTL deformation gradient changes and costal topography. Therefore, traditional flat or curved surface fitting methods are difficult to effectively separate the tidal load displacement for the long wavelength deformation monitoring. It is thus highly recommended in this paper that they should be estimated and corrected carefully in interferometric processing, particularly when long wavelength crustal deformation is targeted. For long time series of deformation monitoring over a wide range of coastal zone (>100 km), if image acquisition time was not away from the astronomical tide and tidal changes in the peak time especially for those Sentinel SAR images with shorter temporal baselines (e.g.12 days), one should consider how to effectively estimate and correct the OTL effects. Besides, InSAR OTL estimation should keep up to date with the latest global ocean models at high spatial resolution or region tidal models integrated with long-term tide gauge observation. |
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| Keywords: | Coastal deformation monitoring Ocean tidal loading displacement SAR interferometry Wide-swath mode Ocean tide model |
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