基于GEE的山东靖海湾岸线和潮滩逐年提取与形态变化分析

GEE-based analysis of year-by-year extraction and shape changes of coastline and tidal flats in Jinghai Bay, Shandong

  • 摘要: 海湾岸线和潮滩具有重要的生态功能和资源价值。针对海湾地物环境复杂、潮汐变动频繁的问题,本文基于谷歌地球引擎,批量构建多特征数据集,综合利用K均值聚类、决策树和多种后处理算法,提出了一种自动提取岸线与潮滩逐年空间信息的方法,选取两者变化较大的典型海湾进行应用验证。利用R语言实现MovMean算法,定量刻画了1985-2023年靖海湾两者形态的年际演变过程,并掌握了其变化特征,结果表明:39年来靖海湾岸线长度由93.17 km增长到133.82 km,总体更为曲折,大部分岸线向海扩张,其中海湾北部岸线扩张最大(129.73 m/a);海湾和潮滩面积均大幅变化且趋势基本一致,分别缩减49.32 km2(41.61%)和11.89 km2(35.96%),岸线形态呈先小幅变化(1985-2001年),后显著变化(2001-2015年),再趋于缓和(2015-2023年)的阶段性变化,这与全国海湾演变特征一致。

     

    Abstract: The coastline and tidal flats of bay play crucial roles in ecology and are valuable for resources. This paper used the Google Earth Engine (GEE) for batch creation of multi-feature datasets to address the intricate environmental conditions and the regular tidal variations in bays. By comprehensively utilizing K-means clustering, decision trees, and diverse post-processing techniques, a method was proposed to automatically extract annual spatial information of the coastline and tidal flats, and typical bays with notable changes were selected for application verification. With the MovMean algorithm developed in the R language, the inter-annual evolution of the coastline and tidal flat shape of Jinghai Bay was quantitatively depicted and characterized from 1985 to 2023. It showed that over the past 39 years, the length of the coastline of Jinghai Bay had increased from 93.17 km to 133.82 km. The coastline had generally become more tortuous, with most of it expanding towards the sea, especially in the northern part of the bay (129.73 m/a). Significant changes and consistent trends had been observed in the bay and tidal flats, resulting in losses of 49.32 km2 (41.61%) and 11.89 km2 (35.96%), respectively. Coastline shape showed a phase of small changes (1985−2001), followed by significant changes (2001−2015), and then moderation (2015−2023), which was consistent with the evolutionary characteristics of the national bays.

     

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