环厦门海域水色变化的多光谱多时相遥感分析

Water colour variation analysis of the coastal waters surrounding Xiamen Island of SE China by multispectral and multitemporal remote sensing measurements

采用基于影像光谱信息建立的水质遥感模型对环厦门海域1989～2003年间的水色变化进行了分析.通过对水体及其所含物质的物理光学性质分析,水质遥感模型的建立可以不依赖于和卫星同步的水质采样数据建立水质遥感.这使得遥感对水色分析的应用更容易,而且还可以利用大量卫星存档数据来进行水质的历史变化分析.使用基于可见光和近红外波段反射率创建的模型研究了离水信号和水中物质（悬浮物和浮游植物）的关系.提出了一套可用于Landsat TM/ETM＋和SPOT 5影像的水专题处理流程,并用于揭示所研究海域中悬浮物和叶绿素浓度的时空变化规律.研究表明,利用基于影像光谱的水质遥感模型,可以快速有效地揭示长时间范围内水色的时空变化.总的看来,环厦门海域的悬浮物浓度在所研究的时期内,有显著的增加,叶绿素的浓度在局部也有明显的升高.最明显的是,高悬浮物浓度的海域面积所占的比例从1989年的0.2%上升到2003年的10.2%.综合分析表明，九龙江河口所带来的巨量悬浮物是该海域最主要的陆源排海物和污染源,过度的水产养殖是另一个主要的污染因子。

The water colour variations of the coastal waters around Xiamen Island from 1989 to 2003 has been analysed through image-spectrum-based models without using in situ data. A water-thematic image processing procedure for Landsat TM/ETM ＋ and SPOT 5 imagery has been proposed and applied to detect spatial and temporal dynamics of suspended solid- and chlorophyll-a-concentrations in the coastal waters. The study shows that the suspended solid concentration （SSC） is the most important parameter to affect water colour, while chlorophyll-a concentration （CAC） is a particularly good estimator of the water trophic level. The image-spectrum-based algorithms can fast and efficiently reveal the spatial and temporal variations of water colour during a long period of time and are especially useful when lack of historical concurrent in situ data. The results from muhitemporal change detection indicate that the SSC in the coastal waters has significantly increased during the study years and CAC has also greatly increased in some areas such as the Maluan Bay. In particular, the high SSC water only accounted for 0.2 % of the study ocean area in 1989 but increased up to 10.2 % of the area in 2003. It is concluded that a huge number of suspended solids loaded in the Jiulong River was the major terrestrial input, and the most important factor resulting in the pollution of the coastal waters when discharging of the loads in the estuary area. In addition, the booming aquicuhure development was another important factor attributed to the pollution.