基于MODIS L1B数据的黄海悬浮体季节性分布的反演

基于2010-2011年春、秋和冬季在黄海3个航次调查取得的悬浮体数据,结合MODIS L1B遥感数据,建立基于MODIS第4波段反射率的表层悬浮体浓度(SSC)的反演模型。利用合成的MODIS月均数据和悬浮体反演模型,反演出黄海表层悬浮体的月际分布,并对形成机制进行探讨。结果显示:黄海悬浮体分布有3个高值区,分别对应3个悬浮体来源,苏北浅滩及成山头高值区来源为海底泥沙的再悬浮,山东半岛北岸高值区来源为由渤海海峡输入黄海的泥沙。黄海悬浮体的分布及扩散具有显著的季节性变化特征,冬季,由于冬季风形成的波浪与沿岸流强盛,黄海3个高值区明显,其中山东半岛北岸与成山头形成一条连续的高悬浮体浓度水体条带;春季,由于波浪及沿岸流减弱,黄海悬浮体浓度显著减小,山东半岛北岸与成山头成为2个独立的高值区,表明其不同的悬浮体来源;夏季,仅苏北浅滩形成由于潮流导致再悬浮的悬浮体浓度高值区;秋季,由于冬季风逐渐加强,黄海悬浮体浓度显著增加,并逐渐过渡到冬季分布状态。

SEASONAL DISTRIBUTION AND VARIATION OF SUSPENDED SEDIMENT IN THE YELLOW SEA IN 2010 BASED ON RETRIEVED MONTHLY DATA FROM MODIS L1B IMAGERY

Based on suspended-sediment concentration (SSC) data collected in spring, autumn and winter from Yellow Sea during 2010-2011, combined with the MODIS L1B remote-sensing data, an empirical model was established to retrieve SSC from the MODIS images. The seasonal variation and distribution of suspended sediment in the Yellow Sea is studied based on the monthly averaged SSC retrieved from monthly averaged MODIS data. The results show that the distribution of suspended sediment in the Yellow Sea presented a significant seasonal variation. Three high SSC areas caused by the strong waves and coastal currents derived from winter storms were found in winter in the Yellow Sea around the Subei shoal, the Chengshantou cape off the Shandong peninsula and the north coast of the Shandong peninsula. The suspended sediment originated from the coast of the Huanghe delta was delivered through the Bohai strait to the Chengshantou and formed a highly turbid water belt along the north coast of Shandong peninsula. The SSC in the Yellow Sea decreased considerably due to weaken waves and coastal currents in spring and resulted in two independent high SSC areas in the north coast of Shandong peninsula and the Chengshantou, indicating that the suspended sediment in these two areas were from different sediment sources. In summer, only one high SSC area was formed around the Subei shoal due to the strong tidal currents in this area. The SSC in the Yellow Sea increased significantly in autumn due to the increasing in intensity of the northerly storms. The winter pattern of suspended-sediment distribution was formed since late autumn in the Yellow Sea.