最优插值法在东海赤潮高发区赤潮生消过程数值模拟中的应用

Optimum interpolation method and its application in numerical simulation of high-frequency harmful algal blooms in the East China Sea

将最优插值法与赤潮数值模型相结合,针对时空分辨率不统一的卫星遥感数据及海洋常规调查数据,进行了东海赤潮高发区海表温度场及海表营养盐浓度场的数据同化研究,并在此基础上进行了该海区春季赤潮过程的数值模拟研究。数据同化结果显示,最优插值数据同化方法不仅在一定程度上修正了海表温度场模拟结果的误差,尤其体现在对赤潮藻的生长影响较大的温度区段18—20℃等值线的南移,而且较为明显地优化了研究海域海表营养盐浓度场,使模拟结果更加接近观测值。对比赤潮过程数值模拟结果发现,在未加同化情况下,海区赤潮藻并未形成大规模赤潮,并且消散较快;而在加入同化后,研究海域交替出现了硅藻及甲藻的大范围赤潮,赤潮生消过程与现场调查数据分析结果较为一致。耦合了最优插值数据同化方法的赤潮数值模型,由于具有改进海洋环境背景场的优势,因此可以在赤潮预报预警工作中得到较好应用。

By combining the optimum interpolation method（OI） and a numerical model of harmful algal bloom（HAB）,data assimilation is conducted for sea surface temperature and nutrients in the high-frequent HAB occurrence area in the East China Sea,using data of non-uniform spatial and temporal resolution from satellite remote sensing and routine marine investigations.The assimilation shows that the process of HAB is simulated numerically and that the model error of sea surface temperature is corrected to some extent,especially in the section from 18 to 20℃ that influences the growth of algae greatly.In addition,the surface nutrients are obviously optimized closer to the observations.The simulation without assimilation does not have any HAB because the concentration of algae dissipates quickly.In contrast,the assimilation shows the processes of large-scale diatom and dinoflagellate HABs occurring alternately,which is more consistent with the in-situ data.With the advantage of improving marine environment background fields,coupled OI data assimilation of HAB can be well applied to forecasting and warning HAB.