2003-2020年黄海水体透明度时空变化特征及影响因素研究

Spatiotemporal variation characteristics and driving factors of water transparency in the Yellow Sea from 2003 to 2020

海水透明度是描述水体光学性质的重要参数,也是海洋环境质量的评价指标。本文基于三波段模型,反演了2003-2020年黄海水体透明度。结果表明,透明度呈近岸向远海逐渐增加的特征,黄海西部为低值区,南黄海中部为高值区。在时间上,透明度呈现下降的趋势。经验正交函数分析表明,第一模态与叶绿素a浓度相关性最强,与悬浮物浓度的相关系数较高,说明海水透明度的变化主要受水体光学组分的影响。第二模态和第三模态表明,海表温度、海表盐度是引起透明度变化的主要协变量。水体透明度长期监测是水质监测和海洋生态系统保护的重要内容。

Water transparency is an important parameter to describe the optical properties of water body and an evaluation index of marine environmental quality.In this study,a three-band ratio model was employed and applied to MODIS remote sensing reflectance data,the water clarity in the Yellow Sea from 2003 to 2020 was estimated.The results show that the transparency gradually increases from the near shore to the open sea,with low value in the western part of the Yellow Sea and high value in the middle part of the South Yellow Sea.In terms of time,the transparency shows a declining trend.Empirical orthogonal function analysis shows that the first mode has the strongest correlation with the concentration of chlorophyll a and a high correlation coefficient with the concentration of suspended matter,indicating that the change of seawater transparency is mainly affected by the optical components of water.The second and third modes show that sea surface temperature and sea surface salinity are the main covariables causing the change of transparency.Long-term monitoring of water transparency is an important part of water quality monitoring and marine ecosystem protection.