Mangrove forests provide valuable societal and ecological services and goods. However, they have been experiencing high annual rates of loss in many parts of the world. In order to evaluate a long-term wetland conserv...Mangrove forests provide valuable societal and ecological services and goods. However, they have been experiencing high annual rates of loss in many parts of the world. In order to evaluate a long-term wetland conservation strategy that compromises urban development with comprehensive wetland ecosystem management, remote sensing techniques were used to analyze the changing mangrove distribution in the Zhanjiang Mangrove Forest National Nature Reserve. Between 1991 and 2000, the mangrove area within the study region declined from 2 264.9 to 2 085.9 ha consistent with an annual decrease of 0.79%. However, there was an overall 34.3% increase in mangrove coverage from 2 085.9 to 2 801.8 ha between 2000 and 2011. Major causes of forest loss include local human pressures in the form of deforestation, conversion to agriculture, and natural forces such as erosion. The recent gain in mangrove forest cover is attributed to eff ective conservation management in the nature reserve area, including intensive mangrove plantation eff orts and increased local awareness of wetland conservation.展开更多
Although remote sensing data have been used to estimate total suspended matter （TSM） in coastal waters, it has limitations when applied to estuary waters in low spatial resolution situations. The spatial resolution ...Although remote sensing data have been used to estimate total suspended matter （TSM） in coastal waters, it has limitations when applied to estuary waters in low spatial resolution situations. The spatial resolution of ocean color satellites such as SeaWiFS and MODIS is usually -1 km, and therefore is not adequate for small, local-scale areas such as the Zhujiang （Pearl） River estuary. In contrast, 30 m-resolution EO-1 Hyperion imagery has potential for studying TSM in localized areas. We measured the surface spectral radiance reflectance of the river estuary water in the visible and near infra-red spectral range. Sensitivity analysis indicated that the ratio of remote sensing reflectance at 813 nm （Rrs（813）） to reflectance at 559 nm （Rrs（559）） could be used to estimate TSM concentration, and a linear relationship was established between the ratio and in-situ TSM concentration. We applied the linear relationship to Hyperion imagery to map TSM concentration in the estuary. The Hyperion imagery provided sufficient spatial resolution to detect spatiotemporal changes in TSM concentrations in the estuary small estuary area. This study demonstrated the usefulness of Hyperion imagery for mapping the distribution of TSM in estuary waters. Keyword： Hyperion; total suspended matter （TSM）; Zhujiang （Pearl） River estuary展开更多
A soil circulation occurs in the south of Cheju Island in the spring. Nutrients and its influence on chloro-phyll a （Chla） around the circulations were studied from April 9 to May 6, 2007. Spring bloom with elevated...A soil circulation occurs in the south of Cheju Island in the spring. Nutrients and its influence on chloro-phyll a （Chla） around the circulations were studied from April 9 to May 6, 2007. Spring bloom with elevated concentrations of Chla was observed during the investigation. High concentrations of phosphate, nitrate and silicate at 0.6, 12, and 8 mmol/m3, respectively, were detected. A low water temperature prevented the growth of phytoplankton. Chla concentrations in the study area might be strongly associated with the high silicate concentration.展开更多
基金Supported by the National Natural Science Foundation of China(No.41340049)the Guangdong Province Science and Technology Plan Project(No.2016A020222016)+1 种基金the Innovation and Strong School Project of Guangdong Ocean University(No.Q16147)the Natural Science Foundation of Guangdong Province(No.2016A030313754)
文摘Mangrove forests provide valuable societal and ecological services and goods. However, they have been experiencing high annual rates of loss in many parts of the world. In order to evaluate a long-term wetland conservation strategy that compromises urban development with comprehensive wetland ecosystem management, remote sensing techniques were used to analyze the changing mangrove distribution in the Zhanjiang Mangrove Forest National Nature Reserve. Between 1991 and 2000, the mangrove area within the study region declined from 2 264.9 to 2 085.9 ha consistent with an annual decrease of 0.79%. However, there was an overall 34.3% increase in mangrove coverage from 2 085.9 to 2 801.8 ha between 2000 and 2011. Major causes of forest loss include local human pressures in the form of deforestation, conversion to agriculture, and natural forces such as erosion. The recent gain in mangrove forest cover is attributed to eff ective conservation management in the nature reserve area, including intensive mangrove plantation eff orts and increased local awareness of wetland conservation.
基金Supported by the National Natural Science Foundation of China(No. 40976106)the Science Foundation Program of Guangdong Ocean University (No. 1012339)the Open Fund of State Key Laboratory of Satellite Ocean Environment Dynamics of Second Institute of Oceanography, SOA (No. SODE1203)
文摘Although remote sensing data have been used to estimate total suspended matter （TSM） in coastal waters, it has limitations when applied to estuary waters in low spatial resolution situations. The spatial resolution of ocean color satellites such as SeaWiFS and MODIS is usually -1 km, and therefore is not adequate for small, local-scale areas such as the Zhujiang （Pearl） River estuary. In contrast, 30 m-resolution EO-1 Hyperion imagery has potential for studying TSM in localized areas. We measured the surface spectral radiance reflectance of the river estuary water in the visible and near infra-red spectral range. Sensitivity analysis indicated that the ratio of remote sensing reflectance at 813 nm （Rrs（813）） to reflectance at 559 nm （Rrs（559）） could be used to estimate TSM concentration, and a linear relationship was established between the ratio and in-situ TSM concentration. We applied the linear relationship to Hyperion imagery to map TSM concentration in the estuary. The Hyperion imagery provided sufficient spatial resolution to detect spatiotemporal changes in TSM concentrations in the estuary small estuary area. This study demonstrated the usefulness of Hyperion imagery for mapping the distribution of TSM in estuary waters. Keyword： Hyperion; total suspended matter （TSM）; Zhujiang （Pearl） River estuary
基金The National Marine Important Charity Special Foundation of China under contract No.201305019the National Natural Science Foundation of China under contract No.41340049+4 种基金Guangdong Planning of Philosophy and Social Science Funding Projectsunder contract No.GD12YGL04Foundation for Distinguished Yong Talents in Higher Education of Guangdong under contract No.2012WYM_0077the Post-Doctoral Starting Fund of Zhejiang under contract No.BSH1301015Second Institute of Oceanography,State Oceanic Administration Post-Doctoral Starting Fund of china under contract Nos JG1208 and JG1319Guangdong Ocean University Doctor Starting Fund of China under contract Nos E11332,E11097 and E12248
文摘A soil circulation occurs in the south of Cheju Island in the spring. Nutrients and its influence on chloro-phyll a （Chla） around the circulations were studied from April 9 to May 6, 2007. Spring bloom with elevated concentrations of Chla was observed during the investigation. High concentrations of phosphate, nitrate and silicate at 0.6, 12, and 8 mmol/m3, respectively, were detected. A low water temperature prevented the growth of phytoplankton. Chla concentrations in the study area might be strongly associated with the high silicate concentration.
