In the present paper, a method is proposed to improve the performance of Artificial Neural Network (ANN) based algorithms for the retrieval of oceanic constituents in Case Ⅱ waters. The ANN-based algorithms have been...In the present paper, a method is proposed to improve the performance of Artificial Neural Network (ANN) based algorithms for the retrieval of oceanic constituents in Case Ⅱ waters. The ANN-based algorithms have been developed based on a constraint condition, which represents, to a certain degree, the correlation between suspended particulate matter (SPM) and pigment (CHL), coloured dissolved organic matter (CDOM) and CHL, as well as CDOM and SPM, found in Case Ⅱ waters. Compared with the ANN-based algorithm developed without a constraint condition, the performance of ANN-based algorithms developed with a constraint conditions is much better for the retrieval of CHL and CDOM, especially in the case of high noise levels; however, there is not significant improvement for the retrieval of SPM.展开更多
The Intergovernmental Panel on Climate Change (IPCC), established by the United Nations and World Meteorological Organization, has determined that humans have very likely influenced a net warming to the Earth from the...The Intergovernmental Panel on Climate Change (IPCC), established by the United Nations and World Meteorological Organization, has determined that humans have very likely influenced a net warming to the Earth from the increase of greenhouse gases, aerosols and land use changes. This warming has caused the amount of ice on the Earth to continue to decrease and sea levels to rise. In addition, extreme precipitation events are happening more often in selected regions of the world. A case study that assesses the impacts of, and adaptations to, these changes in climate is presented here. Two modeling programs, Sim CLIM and Train CLIM, (CLIM Systems, Hamilton, New Zealand) were used to support assessments for water supply, coastal zones and tropical cyclones in a fictitious island group in the South Pacific region. In the case study, a consulting group was “hired” to carry out these assessments. A final analysis and synthesis report were created to help the Ministry of the Environment of the made-up nation decide how to improve the governmental actions to address the real concerns posed by changing climate and sea level. Although a simulated island group is used in this article, there are sincere concerns about climate change and extreme weather events in this part of the world. It is important to address the real and dangerous threat that these islands and people face in the wake of a changing climate and a growing global society.展开更多
Phycocyanin, a functional protein found in blue-green algae, with characteristic absorption peak around 620 nm, can be used to detect the quantity of blue-green algae in waters. Spectral characteristics of phycocyanin...Phycocyanin, a functional protein found in blue-green algae, with characteristic absorption peak around 620 nm, can be used to detect the quantity of blue-green algae in waters. Spectral characteristics of phycocyanin were studied by measuring hyperspectral water leaving radiance and absorption curve, and the results showed that the absorption peak of phycocyanin around 620 nm was evident in the curve of water leaving radiance. Bio-optical model of phycocyanin was set up with analytical methods and calibrated with error analysis. Linear relationship between phycocyanin concentration measured and that retrieved with calibrated bio-optical model (R = 0.755) was better than that retrieved with the band ratio of 709 nm/620 nm (R = 0.729), which proved that the calibration was neces-sary for improving the accuracy of phycocyanin concentration.展开更多
文摘In the present paper, a method is proposed to improve the performance of Artificial Neural Network (ANN) based algorithms for the retrieval of oceanic constituents in Case Ⅱ waters. The ANN-based algorithms have been developed based on a constraint condition, which represents, to a certain degree, the correlation between suspended particulate matter (SPM) and pigment (CHL), coloured dissolved organic matter (CDOM) and CHL, as well as CDOM and SPM, found in Case Ⅱ waters. Compared with the ANN-based algorithm developed without a constraint condition, the performance of ANN-based algorithms developed with a constraint conditions is much better for the retrieval of CHL and CDOM, especially in the case of high noise levels; however, there is not significant improvement for the retrieval of SPM.
文摘The Intergovernmental Panel on Climate Change (IPCC), established by the United Nations and World Meteorological Organization, has determined that humans have very likely influenced a net warming to the Earth from the increase of greenhouse gases, aerosols and land use changes. This warming has caused the amount of ice on the Earth to continue to decrease and sea levels to rise. In addition, extreme precipitation events are happening more often in selected regions of the world. A case study that assesses the impacts of, and adaptations to, these changes in climate is presented here. Two modeling programs, Sim CLIM and Train CLIM, (CLIM Systems, Hamilton, New Zealand) were used to support assessments for water supply, coastal zones and tropical cyclones in a fictitious island group in the South Pacific region. In the case study, a consulting group was “hired” to carry out these assessments. A final analysis and synthesis report were created to help the Ministry of the Environment of the made-up nation decide how to improve the governmental actions to address the real concerns posed by changing climate and sea level. Although a simulated island group is used in this article, there are sincere concerns about climate change and extreme weather events in this part of the world. It is important to address the real and dangerous threat that these islands and people face in the wake of a changing climate and a growing global society.
基金Acknowledgements The authors would like to thank Dr. Zhang Ytmlin for measuring absorption of blue-green algae, and Zhang Xiaoyu, Zhang Xiaofeng, Liu Tao for field measurements. This work was supported by the National Natural Science Foundation of China （Grant No. 40576078）, and Natural Science Foundation of Guangdong Province （Grant No. 5003685）.
文摘Phycocyanin, a functional protein found in blue-green algae, with characteristic absorption peak around 620 nm, can be used to detect the quantity of blue-green algae in waters. Spectral characteristics of phycocyanin were studied by measuring hyperspectral water leaving radiance and absorption curve, and the results showed that the absorption peak of phycocyanin around 620 nm was evident in the curve of water leaving radiance. Bio-optical model of phycocyanin was set up with analytical methods and calibrated with error analysis. Linear relationship between phycocyanin concentration measured and that retrieved with calibrated bio-optical model (R = 0.755) was better than that retrieved with the band ratio of 709 nm/620 nm (R = 0.729), which proved that the calibration was neces-sary for improving the accuracy of phycocyanin concentration.
