遥感方法测定水体中叶绿素含量的核心问题是建立遥感数据和叶绿素含量的定量关系;利用太湖梅梁湾附近水体的实测光谱和水质采样实验室分析,从数量上揭示了位于682nm附近和706nm附近对叶绿素含量估测最重要的两个光谱特征,分别通过比值(R706/R682、R706/R572)、微分、面积、峰高、峰谷距离以及反射峰位置等建立与叶绿素浓度的线性或非线性相关回归模型,通过R2、平均误差以及RMS误差等的分析对比,认为比值和反射峰位置对叶绿素浓度有很好的指示作用,是估测太湖梅梁湾附近水体叶绿素浓度的最好方法,其中与反射峰位置的指数关系R2达0.9199,与R706/R682的直接线性关系R2达0.9038。相对于706nm附近的峰谷距离、峰高以及反射峰面积而言,反射峰的位置是指示叶绿素浓度最敏感的变量;572nm附近、682nm附近以及706nm附近等三个波段对探测叶绿素a具有重要作用。

It is a key problem to analyze quantitatively the correlations between remote sensing data and chlorophyll-a\ncomcentrationfor measuring the chlorophyll-a content with remote sensing method and technology. Two field campaigns were\nmade inMarch and June 2003, respectively. Reflectance spectrawere measuredwith a portable FieldSpec FR spectroradiometer\n(ASD Inc.). Water samples for chlorophyll-a measurementwere collected at the same time guided by some related standards of\nChina. The featuresofthe spectral reflectancewere analyzed in detailwithpeakheight, troughdepth, area surrounded by peak,\ndistance from peak to trough and peak shoulderwidth. And the same result as others is to discover the most important features\nnear 682nm and near 706nm. The regressive linear/nonlinear fitting model were developed respectively between chlorophyll-a\nconcentration and other factors as follows: 1st, the ratio ofreflectance near706nmto reflectance near682nm(R706/R682);2nd,\nthe ratio of reflectance near 706nmto reflectance near 572nm (R706/R572);3rd, the first derivative of reflectance near 690nm\n(R’694);4th, the position ofreflectance peaknear706nm(λmax706);5th, the distance fromreflectance peaknear706nmtotrough\nnear 682nm (Dpeak706-682);6th, the area surrounded by reflectance peak near 706nm (Apeak); and 7th, the height of reflectance\npeak near 706nm (Hpeak706). By comparison ofR2,average error and RMS error respectively, the results showthatR706/R682,\nexponential fitting degreeR2with 0.9199,λmax706, linear fitting degreeR2with 0.9038 can denote chlorophyll-a content and\nthey are betterto predict chlorophyll-a concentrationofwater-bodynearMeiliangbayou inTaihu.The positionofreflectance peak\nnear 706nm is the most sensitive factor to denote chlorophyll-a concentration by comparison of distance from reflectance peak to\nabsorbance value, heightofreflectance peakand area ofreflectance peak. It isvery importantto predict chlorophyll-a contentfor\nthe bands near 572nm, 682nm and 706nm.