海洋一号C/D(HY-1C/D)卫星中国海洋水色水温扫描仪(Chinese Ocean Color and Temperature Scanner,COCTS)主要用于探测海洋水色、水温等要素,这些要素需要经过卫星资料处理才能获取,而几何定位是预处理的核心,直接影响这些要素的质量。C...海洋一号C/D(HY-1C/D)卫星中国海洋水色水温扫描仪(Chinese Ocean Color and Temperature Scanner,COCTS)主要用于探测海洋水色、水温等要素,这些要素需要经过卫星资料处理才能获取,而几何定位是预处理的核心,直接影响这些要素的质量。COCTS具有114°视场角和四元逐点摆扫的特征,据此研究出一套完整的几何定位方法。从0级数据中提取卫星星历,利用插值法从中获取采样时间对应的卫星位置和速度,进而得到轨道(ORB)坐标系到地心旋转(ECR)坐标系的转换矩阵。基于四元逐点摆扫的特征,中心视矢量分别绕X轴、Y轴旋转相应角度,获得扫描行各采样点ORB视矢量,建立视矢量与地球交叉点关系模型,从而对根据波段数据绘制的遥感图像进行地理定位。本文使用插值法替代了传统需要6个轨道根数来计算卫星位置的复杂方法,同时直接计算ORB到ECR的转换矩阵,而不采用传统的两步转换方法。经过多组数据计算及定性定量验证,HY-1C/D COCTS几何定位结果一致;采样像元尺度效应导致从星下点到两侧边缘、从赤道到两极,误差逐渐增大,约在两个像元内。该方法满足一定的定位精度要求,可以用于COCTS的几何定位。展开更多
Prorocentrum donghaiense is one of the most common red tide causative dinoflagellates in the Changjiang （Yangtze） River Estuary and the adjacent area of the East China Sea. It causes large-scale blooms in late sprin...Prorocentrum donghaiense is one of the most common red tide causative dinoflagellates in the Changjiang （Yangtze） River Estuary and the adjacent area of the East China Sea. It causes large-scale blooms in late spring and early summer that lead to widespread ecologic and economic damage. A means for distinguish- ing dinoflagellate blooms from diatom （Skeletonema costatum） blooms is desired. On the basis of measure- ments of remote sensing refectance [Rrs（λ）] and inherent optical parameters, the potential of using a mul- tispectral approach is assessed for discriminating the algal blooms due to P. donghaiense from those due to S. costatum. The behavior of two reflectance ratios [R1 = Rrs（560）/Rrs（532） and Re = Rrs（708）/Rrs（665）], suggests that differentiation of P. donghaiense blooms from diatom bloom types is possible from the current band setup of ocean color sensors. It is found that there are two reflectance ratio regimes that indicate a bloom is dominated by P. donghaiense; （1） R1 〉 1.55 and R2 〈 1.0 or （2） R1 〉 1.75 and R2 ≥ 1.0. Various sensitivity analyses are conducted to investigate the effects of the variation in varying levels of chlorophyll concentration and colored dissolved organic matter （CDOM） as well as changes in the backscattering ratio （bbp/bp） on the efficacy of this muitispectral approach. Results indicate that the intensity and inherent op- tical properties of the algal species explain much of the behavior of the two ratios. Although backscattering influences the amplitude of Rrs（λ）, especially in the 530 and 560 nm bands, the discrimination between P. donghaiense and diatoms is not significantly affected by the variation of bbp/bp. Since aCDOM （440） in coastal areas of the ECS is typically lower than 1.0 m-1 in most situations, the presence of CDOM does not interfere with this discrimination, even as SCDOM varies from 0.01 to 0.026 nm-1. Despite all of these effects, the dis- crimination of P. donghaiense blooms from diatom blooms based on multispectral measurements of Rrs（λ） is feasible.展开更多
Remote sensing has been proven to be an effective means of monitoring red tides. The spectral information is an important basis for establishing a model to monitor red tides. The spectral curves of red tide events are...Remote sensing has been proven to be an effective means of monitoring red tides. The spectral information is an important basis for establishing a model to monitor red tides. The spectral curves of red tide events are analyzed and compared with multiyear monthly averaged spectral curves based on MODIS data from July 2002 to June 2012, as well as spectral differences at the same location during red tide presence and absence. A red tide monitoring algorithm is developed based on the background field to extract the red tide information of the East China Sea （ECS）. With the application of the algorithm in the ECS, the results reveal that the developed model can effectively determine the location of red tides, with good correspondence to the results from an official bulletin. This demonstrates that the algorithm can effectively extract the red tide information.展开更多
The East China Sea （ECS）, one of the largest continental seas, has dynamic hydrology and complex optical characteristics that make ocean color remote-sensing retrieval difficult. The distributions and proportions of...The East China Sea （ECS）, one of the largest continental seas, has dynamic hydrology and complex optical characteristics that make ocean color remote-sensing retrieval difficult. The distributions and proportions of the light absorption coefficients of major ocean color components based on two large-scale investigations in the ECS are presented, showing these features in typical summer and winter seasons. The absorption coefficient aCDOM, aNAp and aphy of colored dissolved organic matter, non-algal particle, and pigment of phytoplankton show a decreasing trend from the coast to the outer shelf. According to the aeDOM distribution at 440 nm, the Changjiang River plume shows an abnormal southeastward transport. An extremely high aNaP value patch at 440 nm is present in the middle coast. The chlorophyll-a-specific phytoplankton pigment absorption （a^hy） is much higher in winter than in summer, which may cause serious underestimated results when applying the averaged aphy into remote-sensing algorithms for chlorophyll concentration retrieval. The importance of phytoplankton size was evident in outer shelf waters. The absorption of aCDOM （440） is a dominant component accounting for over half of the total seawater absorption in summer. The aNAP（440） accounts for 64% of the absorption of the ECS coastal area in winter.展开更多
文摘海洋一号C/D(HY-1C/D)卫星中国海洋水色水温扫描仪(Chinese Ocean Color and Temperature Scanner,COCTS)主要用于探测海洋水色、水温等要素,这些要素需要经过卫星资料处理才能获取,而几何定位是预处理的核心,直接影响这些要素的质量。COCTS具有114°视场角和四元逐点摆扫的特征,据此研究出一套完整的几何定位方法。从0级数据中提取卫星星历,利用插值法从中获取采样时间对应的卫星位置和速度,进而得到轨道(ORB)坐标系到地心旋转(ECR)坐标系的转换矩阵。基于四元逐点摆扫的特征,中心视矢量分别绕X轴、Y轴旋转相应角度,获得扫描行各采样点ORB视矢量,建立视矢量与地球交叉点关系模型,从而对根据波段数据绘制的遥感图像进行地理定位。本文使用插值法替代了传统需要6个轨道根数来计算卫星位置的复杂方法,同时直接计算ORB到ECR的转换矩阵,而不采用传统的两步转换方法。经过多组数据计算及定性定量验证,HY-1C/D COCTS几何定位结果一致;采样像元尺度效应导致从星下点到两侧边缘、从赤道到两极,误差逐渐增大,约在两个像元内。该方法满足一定的定位精度要求,可以用于COCTS的几何定位。
基金The National Basic Research Program of China (973 Program) under contract No.2013CB430302the National High Technology Research and Development Program of China (863 Program) under contract No.2007AA092002+2 种基金the National Natural Science Foundation of China under contract No.41206170the public science and technology research funds projects of the ocean under contract No.201005030scientific research fund of the Second Institute of Oceanography,SOA under contract No.JG1212
文摘Prorocentrum donghaiense is one of the most common red tide causative dinoflagellates in the Changjiang （Yangtze） River Estuary and the adjacent area of the East China Sea. It causes large-scale blooms in late spring and early summer that lead to widespread ecologic and economic damage. A means for distinguish- ing dinoflagellate blooms from diatom （Skeletonema costatum） blooms is desired. On the basis of measure- ments of remote sensing refectance [Rrs（λ）] and inherent optical parameters, the potential of using a mul- tispectral approach is assessed for discriminating the algal blooms due to P. donghaiense from those due to S. costatum. The behavior of two reflectance ratios [R1 = Rrs（560）/Rrs（532） and Re = Rrs（708）/Rrs（665）], suggests that differentiation of P. donghaiense blooms from diatom bloom types is possible from the current band setup of ocean color sensors. It is found that there are two reflectance ratio regimes that indicate a bloom is dominated by P. donghaiense; （1） R1 〉 1.55 and R2 〈 1.0 or （2） R1 〉 1.75 and R2 ≥ 1.0. Various sensitivity analyses are conducted to investigate the effects of the variation in varying levels of chlorophyll concentration and colored dissolved organic matter （CDOM） as well as changes in the backscattering ratio （bbp/bp） on the efficacy of this muitispectral approach. Results indicate that the intensity and inherent op- tical properties of the algal species explain much of the behavior of the two ratios. Although backscattering influences the amplitude of Rrs（λ）, especially in the 530 and 560 nm bands, the discrimination between P. donghaiense and diatoms is not significantly affected by the variation of bbp/bp. Since aCDOM （440） in coastal areas of the ECS is typically lower than 1.0 m-1 in most situations, the presence of CDOM does not interfere with this discrimination, even as SCDOM varies from 0.01 to 0.026 nm-1. Despite all of these effects, the dis- crimination of P. donghaiense blooms from diatom blooms based on multispectral measurements of Rrs（λ） is feasible.
基金The National High Technology Research and Development Program(863 Program)of China under contract No.2007AA092002the National Basic Research Program(973 Program)of China under contract No.2013CB956503
文摘Remote sensing has been proven to be an effective means of monitoring red tides. The spectral information is an important basis for establishing a model to monitor red tides. The spectral curves of red tide events are analyzed and compared with multiyear monthly averaged spectral curves based on MODIS data from July 2002 to June 2012, as well as spectral differences at the same location during red tide presence and absence. A red tide monitoring algorithm is developed based on the background field to extract the red tide information of the East China Sea （ECS）. With the application of the algorithm in the ECS, the results reveal that the developed model can effectively determine the location of red tides, with good correspondence to the results from an official bulletin. This demonstrates that the algorithm can effectively extract the red tide information.
基金The National Basic Research Program ("973" Program) of China under contract No.2009CB421202the National Natural Science Foundation of China under contract Nos 40976110 and 40706061the National High Technology Research and Development Program ("863" Program) of China under contract No.2008AA09Z104
文摘The East China Sea （ECS）, one of the largest continental seas, has dynamic hydrology and complex optical characteristics that make ocean color remote-sensing retrieval difficult. The distributions and proportions of the light absorption coefficients of major ocean color components based on two large-scale investigations in the ECS are presented, showing these features in typical summer and winter seasons. The absorption coefficient aCDOM, aNAp and aphy of colored dissolved organic matter, non-algal particle, and pigment of phytoplankton show a decreasing trend from the coast to the outer shelf. According to the aeDOM distribution at 440 nm, the Changjiang River plume shows an abnormal southeastward transport. An extremely high aNaP value patch at 440 nm is present in the middle coast. The chlorophyll-a-specific phytoplankton pigment absorption （a^hy） is much higher in winter than in summer, which may cause serious underestimated results when applying the averaged aphy into remote-sensing algorithms for chlorophyll concentration retrieval. The importance of phytoplankton size was evident in outer shelf waters. The absorption of aCDOM （440） is a dominant component accounting for over half of the total seawater absorption in summer. The aNAP（440） accounts for 64% of the absorption of the ECS coastal area in winter.
