基于GOCI提取东海近几年赤潮信息及时序分析

赤潮已经成为我国东海最普遍的海洋灾害之一.利用卫星手段监测赤潮也由来已久.采用Geostationary Ocean Color Imager(GOCI)静止卫星对东海近几年的赤潮进行了监测和分析.研究表明:1)利用Quick Atmospheric Correction(QUAC)获取GOCI的归一化离水辐射率,其中nLw(555nm)作为赤潮事件的特征波段来监测赤潮是有效的;2)以nLw(555nm)为峰值且通过小于1.5mW·cm~(-2)·sr~(-1)·μm~(-1)这一阀值信息来监测中国东海3次不同时间和区域的赤潮事件.3次事件分别为2011年5月东海原甲藻事件、2011年7月中肋骨条藻事件和2014年5月东海原甲藻事件;3)赤潮面积的日变化主要受有效光合辐射和潮位的影响.通过QUAC获取归一化离水辐射率GOCI-nLw(550nm),将nLw(555nm)作为特征波段来获取赤潮信息,并结合光照强度、潮位、温度等参数,分析了赤潮面积日变化的可能原因.

Using GOCI extracting information of red tide for time-series analysing in East China Sea

In the East China Sea, red tide has become one of the most common marine disasters. Using satellite detecting red tide has already begun for a long time. Geostationary Ocean Color Imager (GOCI) has been used to monitor and analyze the red tide which happened recently in the East China Sea. The results demonstrate that:1)The normalized water leaving radiance was obtained using Quick Atmospheric Correction (QUAC) for GOCI, and it was effective that normalized water leaving radiance (nLw) 555 nm was chose as the characteristic to monitor red tide; 2) Temporal and spatial distribution of red tide in East China Sea was detected by the threshold of nLw (555 nm) which is peak and less than 1.5 mW·cm^-2·sr^-1·μm^-1. The three events were that Prorocentrum donghaiense in May 2011, the Skeletonema costatum in July 2011, Prorocentrum donghaiense in May 2014, respectively. 3) The red tide area was mainly affected by the tidal and photosynthetically active radiation during a day.NLw (555 nm) was obtained by the atmospheric correction of GOCI through QUAC. And, the red tide area was obtained by the threshold of nLw (555 nm). Combining the photosynthetically active radiation, temperature and tide, the potential reason of variety of red tide during a day was analyzed.