应用TM数据估算沿岸海水表层时绿素浓度模型研究

Study on Modeling Chlorophyll Concentration of Surface Coastal Water Using TM Data

本研究以大亚湾为实验区，以陆地卫星ＴＭ数据为信息源，结合表层海水叶绿素浓度实测资料建立模型。在对叶绿素光谱特征及遥感估算叶绿素浓度机理研究基础上，选取了ＴＭＩ—ＴＭ４波段的７５种波段组合为子因素，以叶绿素浓度为母因素，利用灰色系统理论，分析各波段组合与叶绿素浓度之间的关联度。将关联度最大的５种波段组合分别建模，得到５个估算表层海水叶绿素浓度的反演模型。误差分析表明，各模型的最大相对误差在１９％以下，平均绝对相对误差在１１．２％以下，相对标准误差在６．７％以下，模型精度较高。研究表明：（ＴＭ３×ＴＭ４）是估算沿岸海水表层叶绿素浓度的最佳波段组合，采用（ＴＭ３×ＴＭ４）与ＴＭ１、ＴＭ２或ｌｎ（ＴＭ十ＴＭ２）、Ｉｎ（ＴＭ１×ＴＭ２）之比值并不能改善估算精度。

Some models for estimating chlorophyll concentration are developed in this study by taking Daya Bay as an experimental site and Landsat-5 TM (Thematic Mapper) data as information resources, and combining the survey data of chlorophyll concentration in the surface coastal water. On the base of studying the spectral characteristics of chlorophyll and the mechanism of surveying chlorophyll concentration using remote sensing data, taking 75 band compositions of TM1-TM4 bands as the subfactors and the chlorophyll concentration as the mother factor, factor analysis was carried out by using the Grey System Theory. According to the results of the factor analysis, 5 band compositions, which have greater correlative degree to the mother factor, are selected for modeling. The error analysis shows that these models have high accuracy with the mean absolute relative error less than 11. 2% and relative standard error less than 6. 7%. Unlike the general way taking the ratio of TM2 or TM3 to TM1 as the best band compositions, this study shows that (TM3×TM4) is the best band composition for estimating chlorophyll concentration of the surface layer of coastal water, and the estimated accuracy can not be advanced by using the ratio of (TM3×TM4) to TM1 or TM2 or In(TM1+TM2) or In(TM1×TM2).