Using second-derivative spectrum to estimate Chlorophyll-a concentration in turbid estuarine waters

Hyperspectral technique is considered as one promising tool to solve the problems in monitoring optically-complex waters, which can be applied in optical sensors on board bouy, plane and satellite. In order to apply the technique in the in-situ chlorophyll monitoring of estuarine turbid waters, two cruises were carried out in May, 2004 and August, 2006, respectively, in Pearl River Estuary, China. In the cruises, water samples were collected at each sample station, a portable field spectroradiometer was used simultaneously to measure the downwelling sky radiance, and upwelling radiance of water and reference plaque, and the reflectance was calculated out. Further, the original reflectance spectra with 0.38 nm spectral resolution were resampled to 10 run resolution, and then derivative spectra were processed. The results of correlation analysis between the chlorophyll-a concentrations and derivative spectra indicate that the second derivative spectra especially at 670 nm can be used to estimate chlorophyll-a concentration of turbid estuarine waters, which suggests a new way for the in-situ chlorophyll measurement in the optically-complex waters

Assessing oil spill risk in the Chinese Bohai Sea: A case study for both ship and platform related oil spills

Many oil spill accidents have occurred in the Chinese Bohai Sea recently because of extensive offshore oil exploitation and maritime transportation. In this study we made an attempt towards the development of a probabilistic model assessing the oil spill risks for the Bohai Sea. We utilized satellite images together with historic accident data from 1973 to 2002 and information from literature to establish probability of oil spills, which was then adjusted for the consequence of spill impacts. The assessment represented a distribution of oil spill risk in the study area. Totally, seven high risk zones have been identified, providing useful information on the optimal locations for oil spill recovery and cleanup equipment to improve spill-response readiness in the region. We anticipated that the results would contribute to the mitigation of the harmful effects of future oil spills in the Bohai Sea, if the presented model was used with care. (C) 2014 Elsevier Ltd. All rights reserved.Many oil spill accidents have occurred in the Chinese Bohai Sea recently because of extensive offshore oil exploitation and maritime transportation. In this study we made an attempt towards the development of a probabilistic model assessing the oil spill risks for the Bohai Sea. We utilized satellite images together with historic accident data from 1973 to 2002 and information from literature to establish probability of oil spills, which was then adjusted for the consequence of spill impacts. The assessment represented a distribution of oil spill risk in the study area. Totally, seven high risk zones have been identified, providing useful information on the optimal locations for oil spill recovery and cleanup equipment to improve spill-response readiness in the region. We anticipated that the results would contribute to the mitigation of the harmful effects of future oil spills in the Bohai Sea, if the presented model was used with care. (C) 2014 Elsevier Ltd. All rights reserved