Park Kyung-Ae, Cha Na-Yeon, Jeong Kwang-Young, Byun Do-Seong, Choi Byoung-Ju, Lee Joon-Soo
Department of Earth Science Education, Seoul National University, Seoul, Republic of Korea.
Center for Education Research, Seoul National University, Seoul, Republic of Korea.
Sci Rep. 2025 Aug 2;15(1):28240. doi: 10.1038/s41598-025-13428-y.
A monthly climatology of long-term optical water types in the East China Sea (ECS), covering the region around the Ieodo Ocean Research Station (I-ORS) and the Yangtze River discharge (YZRD) area, was constructed using two decades of satellite MODIS reflectance data. SMAP salinity data revealed the gradual seasonal dispersion of low-salinity water from the YZR mouth toward I-ORS, particularly intensifying in summer. Despite the influx of riverine water over I-ORS, satellite-based optical water type analysis indicated that I-ORS area maintained its clearest water types during summer-a novel finding. Cross-wavelet analysis between long-term YZRD and Chl-a concentrations at I-ORS displayed intermittent insignificant correlations without sustained patterns. Spatial distribution of phase-lag regression results between the Chl-a and YZRD revealed non-direct routes as northeastward spreading from the river mouth and a counterclockwise dispersion path south of I-ORS. This pattern aligned with riverine particle-tracking experiments following surface currents, underscoring the role of currents in transporting nutrients from the river, which is crucial for Chl-a blooms in the summer oligotrophic environment. Our results highlight the influence of riverine discharge on ECS marine conditions, emphasizing the role of physical and biological interactions in shaping Chl-a distributions within marine ecosystems in summer oligotrophic environment.
利用二十年的卫星中分辨率成像光谱仪（MODIS）反射率数据，构建了东海（ECS）长期光学水型的月气候学，覆盖了济州海洋研究站（I-ORS）周边地区和长江入海口（YZRD）区域。土壤湿度主动被动遥感卫星（SMAP）盐度数据显示，低盐度水从长江入海口向I-ORS逐渐季节性扩散，在夏季尤为强烈。尽管有河流淡水流入I-ORS，但基于卫星的光学水型分析表明，I-ORS区域在夏季保持了最清澈的水型——这是一个新发现。I-ORS长期长江入海口流量（YZRD）与叶绿素a浓度之间的交叉小波分析显示，两者之间存在间歇性的不显著相关性，且无持续模式。叶绿素a与YZRD之间的相位滞后回归结果的空间分布显示，其路径并非直接从河口向东北方向扩散，而是在I-ORS以南呈逆时针扩散路径。这种模式与沿表层洋流进行的河流颗粒追踪实验结果一致，强调了洋流在输送河流养分中的作用，这对夏季贫营养环境中的叶绿素a水华至关重要。我们的研究结果突出了河流排放对东海海洋状况的影响，强调了物理和生物相互作用在塑造夏季贫营养环境中海洋生态系统内叶绿素a分布方面的作用。
