基于哨兵2号卫星遥感影像的2018年苏北浅滩漂浮绿藻时空分布特征研究

The spatial and temporal distribution of floating green algae in the Subei Shoal in 2018 retrieved by Sentinel-2 images

黄海浒苔绿潮自2007年以来连年暴发,但对漂浮绿藻在其源地—苏北浅滩的分布、发生和发展过程仍缺乏精细刻画。本文主要采用哨兵2号卫星遥感影像,对2018年苏北浅滩的漂浮绿藻信息进行提取,结合地形、微波+红外融合海表温度和CCMP海面风场数据,分析了影响漂浮绿藻时空分布的重要环境因子。结果表明:漂浮绿藻于5月23日在苏北浅滩南部首次通过遥感影像被探测到,在6月逐渐向北发展扩大,在7月中旬消失。漂浮绿藻最早可追溯至浅滩中心紫菜养殖筏架区边缘,而后沿潮沟形成宽度为10~200 m、断续绵延数十千米的条带。在黄海绿潮发展过程中,浅滩持续向北及外海输送漂浮绿藻。在浅滩以北,漂浮绿藻的分布和漂移与海面风向一致。本研究结果可为黄海绿潮的早期预警和防控提供依据。

Since 2007,the annually Yellow Sea green tide(YSGT)have caused significant economic losses and serious social impacts in China.Previous research indicated that the floating green algal was originated from Subei Shoal,southwestern Yellow Sea,while the early development of floating green algae in the shoal remains unclear.Using Sentinel-2 high-resolution images,we extracted the floating green algae information in 2018.The effects of topography,sea surface temperature and sea surface wind on the distribution and development of floating green algae were studied using CCMP sea wind data and Microwave+IR Signal Fusion SST sea surface temperature data.The results showed that the first sign of floating green algae by satellites was detected in the south of Subei Shoal on May 23.The floating green algae expanded northwards in June,and decayed on July 13.The floating green algae could be traced back to the edge of Prophyra aquaculture area,aggregated and formed stripes along the sand grooves in the Subei Shoal.These stripes stretched tens of kilometers with width of 10–200 m and existed throughout the development of YSGT.In the region of north to Subei Shoal,the distribution and drifting of floating green algae were highly associated with wind directions.Based on our research,it is feasible and cost-effective to collect and remove the floating algae in the Subei Shoal.