Quantification of floating macroalgae blooms using the scaled algae index

CORC > 烟台海岸带研究所 > 中国科学院烟台海岸带研究所 > 中科院海岸带环境过程与生态修复重点实验室

	Quantification of floating macroalgae blooms using the scaled algae index
	Garcia, Rodrigo A.1; Fearns, Peter 1; Keesing, John K.2,3; Liu, Dongyan3
刊名	JOURNAL OF GEOPHYSICAL RESEARCH-OCEANS
	2013
卷号	118 期号:1 页码:26-42
关键词	Fractional Vegetation Cover Water-leaving Radiance Seaweed Aquaculture Yellow Sea China Modis Fluorescence Expansion Seawifs Meris
ISSN号	0148-0227
通讯作者	Garcia, RA (reprint author), Curtin Univ Technol, Remote Sensing & Satellite Res Grp, GPO Box U1987, Perth, WA 6845, Australia. rodrigo.garcia@postgrad.curtin.edu.au
产权排序	[Garcia, Rodrigo A.; Fearns, Peter] Curtin Univ Technol, Remote Sensing & Satellite Res Grp, Perth, WA 6845, Australia; [Keesing, John K.] CSIRO Wealth Oceans Flagship, Marine & Atmospher Res, Wembley, WA, Australia; [Keesing, John K.; Liu, Dongyan] Chinese Acad Sci, Yantai Inst Coastal Zone Res, Yantai, Shandong, Peoples R China
文献子类	Article
英文摘要	Quantifying the spatial coverage of floating macroalgae from satellite imagery, using methods such as the normalized difference vegetation index (NDVI) and the floating algae index (FAI), requires the use of a scene-wide threshold to isolate and then compute the number of floating macroalgae pixels. The problem faced is the sensitivity of the NDVI and, to a lesser extent, the FAI to radiance contributions from atmospheric aerosols and turbid water. Both these factors can vary significantly across a satellites' field-of-view generating irregular apparent reflectance of ocean and floating macroalgae pixels across an NDVI/FAI scene, leading to inaccuracies in spatial coverage estimates. We present a simple image processing algorithm, termed the scaled algae index (SAI), that removes any variability present in ocean and floating macroalgae pixels in NDVI or FAI imagery. The SAI does this by subtracting a given pixel's index by that of a local ocean pixel, effectively scaling ocean pixels to values near zero, and macroalgae pixels to positive values. The SAI algorithm has been tested on NDVI and FAI scenes of the 2008/2009 floating macroalgae blooms that occurred in the Yellow Sea, China. These SAI images show a major reduction in variability with scene-wide histograms being unimodal. Histogram analysis also indicates that sufficient contrast exists between ocean and floating macroalgae pixels to enable segmentation by a scene-wide threshold. A semiautomated threshold determination procedure is also presented, which together with the SAI algorithm can be used to compute accurate estimates of the spatial coverage of floating macroalgae.; Quantifying the spatial coverage of floating macroalgae from satellite imagery, using methods such as the normalized difference vegetation index (NDVI) and the floating algae index (FAI), requires the use of a scene-wide threshold to isolate and then compute the number of floating macroalgae pixels. The problem faced is the sensitivity of the NDVI and, to a lesser extent, the FAI to radiance contributions from atmospheric aerosols and turbid water. Both these factors can vary significantly across a satellites' field-of-view generating irregular apparent reflectance of ocean and floating macroalgae pixels across an NDVI/FAI scene, leading to inaccuracies in spatial coverage estimates. We present a simple image processing algorithm, termed the scaled algae index (SAI), that removes any variability present in ocean and floating macroalgae pixels in NDVI or FAI imagery. The SAI does this by subtracting a given pixel's index by that of a local ocean pixel, effectively scaling ocean pixels to values near zero, and macroalgae pixels to positive values. The SAI algorithm has been tested on NDVI and FAI scenes of the 2008/2009 floating macroalgae blooms that occurred in the Yellow Sea, China. These SAI images show a major reduction in variability with scene-wide histograms being unimodal. Histogram analysis also indicates that sufficient contrast exists between ocean and floating macroalgae pixels to enable segmentation by a scene-wide threshold. A semiautomated threshold determination procedure is also presented, which together with the SAI algorithm can be used to compute accurate estimates of the spatial coverage of floating macroalgae.
学科主题	Oceanography
URL标识	查看原文
WOS关键词	FRACTIONAL VEGETATION COVER ; WATER-LEAVING RADIANCE ; SEAWEED AQUACULTURE ; YELLOW SEA ; CHINA ; MODIS ; FLUORESCENCE ; EXPANSION ; SEAWIFS ; MERIS
WOS研究方向	Oceanography
语种	英语
WOS记录号	WOS:000317836100003
公开日期	2013-08-15
内容类型	期刊论文
源URL	[http://ir.yic.ac.cn/handle/133337/6657]
专题	烟台海岸带研究所_中科院海岸带环境过程与生态修复重点实验室烟台海岸带研究所_近岸生态与环境实验室
作者单位	1.Curtin Univ Technol, Remote Sensing & Satellite Res Grp, Perth, WA 6845, Australia 2.CSIRO Wealth Oceans Flagship, Marine & Atmospher Res, Wembley, WA, Australia 3.Chinese Acad Sci, Yantai Inst Coastal Zone Res, Yantai, Shandong, Peoples R China
推荐引用方式 GB/T 7714	Garcia, Rodrigo A.,Fearns, Peter,Keesing, John K.,et al. Quantification of floating macroalgae blooms using the scaled algae index[J]. JOURNAL OF GEOPHYSICAL RESEARCH-OCEANS,2013,118(1):26-42.
APA	Garcia, Rodrigo A.,Fearns, Peter,Keesing, John K.,&Liu, Dongyan.(2013).Quantification of floating macroalgae blooms using the scaled algae index.JOURNAL OF GEOPHYSICAL RESEARCH-OCEANS,118(1),26-42.
MLA	Garcia, Rodrigo A.,et al."Quantification of floating macroalgae blooms using the scaled algae index".JOURNAL OF GEOPHYSICAL RESEARCH-OCEANS 118.1(2013):26-42.