渤海表层悬浮物浓度长期变化(2003—2014年)的卫星反演研究

Long-Term Variation of Suspended Sediment Concentration in the Bohai Sea Based on Retrieved Satellite Data

受气候变化和人类活动的影响,近年来渤海悬浮物浓度分布发生了较大变化,进而影响了渤海海洋生态环境、海洋资源分布以及海岸工程的建设。由于渤海悬浮物浓度长期观测资料较少,目前对于渤海悬浮物浓度分布的长期变化趋势和影响机制尚不清楚。本文利用2003—2014年的MODIS卫星遥感数据,反演了渤海表层悬浮物浓度的空间分布形态,并对其长期的变化趋势和影响机制进行了研究。研究结果表明,除了明显的季节变化特征外,渤海表层悬浮物浓度从2003年到2014年有明显的下降趋势,整个渤海表层悬浮物浓度年均下降幅度为1.49%(0.22mg·L^(-1)·a^(-1))。其中莱州湾表层悬浮物浓度年均下降幅度最大,为3.47%(1.08mg·L^(-1)·a^(-1));辽东湾次之,为1.51%(0.17mg·L^(-1)·a^(-1));而渤海湾的年均下降幅度为1.40%(0.33mg·L^(-1)·a^(-1)),中央海区表层悬浮物浓度没有下降趋势。近十几年来渤海表层悬浮物浓度下降可能与渤海海区风速减弱、黄河调水调沙造成的入海泥沙粒径增大以及莱州湾、渤海湾内的围海造田有关。

Climate change and human activities greatly affect the suspended sediment concentration（SSC）of the Bohai Sea.As a result,the ecology environment,fishery resources and coastal engineering structures in the Bohai Sea are potentially threatened by these changes.However,due to the lack of the long-term SSC observation field data,it is still not clear about the long-termvariation of the SSC in the Bohai Sea and what mechanisms dominant the variation.Based on the MODIS satellite data（2003—2014）,spatial and seasonal variations of SSC in the Bohai Sea are studied.The results show that SSC of the Bohai Sea show clear long-termvariation besides the seasonal variation.The sea surface SSC in the Bohai Sea decrease 1.49%annually（0.22mg·L（-1）·a（-1））.The Laizhou Bay shows the highest decrease of SSC with decrease speed of 3.47%/a（1.08mg·L（-1）·a（-1））.The SSC of the Liaodong Bay decreases1.51% annually（0.17mg·L（-1）·a（-1））while the SSC decrease speed of the BohaiBay is 1.40%/a（0.33mg·L（-1）·a（-1））.No obvious decrease trend is found in the Central Bohai Sea.The decrease trend of the SSC in the Bohai Sea is probably related to the long-term decrease of the wind speed in the Bohai Sea,the increase of the sea bed sediment size caused by the water and sediment regulation of the Yellow River and the reclamation in the Laizhou Bay and Bohai Bay.