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Spectral Characterization of Colored Dissolved Organic Matter for Productive Inland Waters and Its Source Analysis 被引量:6
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作者 SONG Kaishan LI Lin +3 位作者 Lenore TEDESCO Nicolas CLERCIN LI Linhai SHI Kun 《Chinese Geographical Science》 SCIE CSCD 2015年第3期295-308,共14页
This study examined the spatiotemporal dynamics of colored dissolved organic matter (CDOM) and spectral slope (S), and further to analyze its sources in three productive water supplies (Eagle Creek, Geist and Mor... This study examined the spatiotemporal dynamics of colored dissolved organic matter (CDOM) and spectral slope (S), and further to analyze its sources in three productive water supplies (Eagle Creek, Geist and Morse reservoirs) from Indiana, USA. The re- sults showed that he absorption coefficient aCDOM(440) ranged from 0.37 m-1 to 3.93 m-1 with an average of 1.89 ± 0.76 m-1 (±SD) for the aggregated dataset, and S varied from 0.0048 nm -1 to 0.0239 nm-1 with an average of 0.0108 ±0.0040 nmI. A significant relation- ship between S and aCDOM(440) can be fitted with a power equation (S = 0.013 × aCDOM(440)-0.42, R2 = 0.612), excluding data from Geist Reservoir during high flow (12 April 2010) and the Morse Reservoir on 25 June 2010 due to a T-storm achieves even higher determina- tion coefficient (R2 = 0.842). Correlation analysis indicated that aCDOM(440) has strong association with inorganic suspended matter (ISM) concentration (0.231 〈 R2 〈 0.786) for each of the field surveys, and this trend followed the aggregated datasets (R2 = 0.447, p 〈 0.001). In contrast, chlorophyll-a was only correlated with aCDOM(440) in summer and autumn (0.081 〈 R2 〈 0.763), indicating that CDOM is mainly from terrigenous sources in early spring and that phytoplankton contributed during the algal blooming season. The S value was used to characterize CDOM origin. The results indicate that the CDOM source is mainly controlled by hydrological varia- tions, while phytoplankton originated organic matter also closely linked with CDOM dynamics in three productive reservoirs. 展开更多
关键词 absorption coefficient colored dissolved organic matter (CDOM) CHLOROPHYLL-A spectral slope (S) inorganic suspendedmatter (ISM)
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Characterization of Water Constituents Spectra Absorption in Chagan Lake of Jilin Province, Northeast China 被引量:1
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作者 WANG Yuandong LIU Dianwei +6 位作者 SONG Kaishan DU Jia WANG Zongming ZHANG Bai TANG Xuguang LEI Xiaochun WU Yanqing 《Chinese Geographical Science》 SCIE CSCD 2011年第3期334-345,共12页
Research on the optical characteristics of water color constituents in Chagan Lake of Jilin Province,Northeast China was carried out in order to investigate the variability of the spectra absorption parameters as inpu... Research on the optical characteristics of water color constituents in Chagan Lake of Jilin Province,Northeast China was carried out in order to investigate the variability of the spectra absorption parameters as inputs to bio-optical models and remote sensing algorithms for converting observed spectral signals into water quality information.Samples of total particulates,non-algal particles and colored dissolved organic matter (CDOM) were first prepared by quantitative filter technique (QFT) and then absorption coefficients of these color producing agents were determined by spectrophotometry.Spectral characteristics of absorption coefficients by total particulate matter,spectral specific absorption dependency on chlorophyll concentration (Chl-a) of phytoplankton,spectral absorption slopes variation for CDOM and non-algal particles and their corresponding reasons were examined and clarified over five months of 2009 and 2010 in this study.Results suggest that total particulate spectral absorption in Chagan Lake is mainly dominated by non-algal particles in most cases,but phytoplankton could be the dominant contributor when chlorophyll concentration is high (up to 84.48 mg/m3 in autumn 2010).The specific absorption coefficients of phytoplankton particulate (a*ph(λ)) dependency on Chl-a is significantly variable due to relative contributions of package effect and accessory pigments,and the parameters of power function are clearly biased on a long time span.The sources of variability in spectral absorption slopes of CDOM and non-algal particles are mainly attributed to the changing proportions of high molecular weight humic acids and mineral suspended sediments in waters,respectively. 展开更多
关键词 colored dissolved organic matter spectra absorption water constituents spectral slope Chagan Lake
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Characteristics of oceanic mesoscale variabilities associated with the inverse kinetic energy cascade
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作者 Mengmeng Li Zhiliang Liu +1 位作者 Jianing Li Chongguang Pang 《Acta Oceanologica Sinica》 SCIE CAS CSCD 2021年第7期42-57,共16页
Oceanic geostrophic turbulence theory predicts significant inverse kinetic energy (KE) cascades at scales larger than the energy injection wavelength. However,the characteristics of the mesoscale variabilities associa... Oceanic geostrophic turbulence theory predicts significant inverse kinetic energy (KE) cascades at scales larger than the energy injection wavelength. However,the characteristics of the mesoscale variabilities associated with the inverse KE cascade in the real oceans have not been clear enough up to now. To further examine this problem,we analyzed the spectral characteristics of the oceanic mesoscale motions over the scales of inverse KE cascades based on high-resolution gridded altimeter data. The applicability of the quasigeostrophic (QG) turbulence theory and the surface quasigeostrophic (SQG) turbulence theory in real oceans is further explored. The results show that the sea surface height (SSH) spectral slope is linearly related to the eddy-kinetic-energy (EKE) level with a high correlation coefficient value of 0.67. The findings also suggest that the QG turbulence theory is an appropriate dynamic framework at the edge of high-EKE regions and that the SQG theory is more suitable in tropical regions and low-EKE regions at mid-high latitudes. New anisotropic characteristics of the inverse KE cascade are also provided. These results indicate that the along-track spectrum used by previous studies cannot reveal the dynamics of the mesoscale variabilities well. 展开更多
关键词 mesoscale eddy inverse cascade scalar wavenumber spectrum spectral slope ANISOTROPY
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Spatiotemporal characteristics and remote sensing estimation of colored dissolved organic matter around the Leizhou Peninsula
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作者 Dongyang FU Shiyun WEI +3 位作者 Guo YU Yafei LUO Huabing XU Zhaoguang CHEN 《Journal of Oceanology and Limnology》 SCIE CAS CSCD 2023年第4期1405-1424,共20页
Colored dissolved organic matter(CDOM)is an important optically active substance in marine environment.Its biochemical conservatism makes it an important indicator to offshore pollution process.Monitoring the content,... Colored dissolved organic matter(CDOM)is an important optically active substance in marine environment.Its biochemical conservatism makes it an important indicator to offshore pollution process.Monitoring the content,composition,and diffusion process of CDOM is a good approach to analyze the terrestrial input,optical properties,and ecological environment of offshore areas.The spatiotemporal characteristics of CDOM around the Leizhou Peninsula were analyzed based on field observation data collected in the autumn 2020 and spring 2021,and an empirical inversion model of the ag(355)(absorption coefficient at 355 nm)and spectral slope(Sg)(g stands for gelbstoff/gilvin,which is called CDOM)based on Sentinel-3A ocean and land color instrument(OLCI)images was constructed.The results show(1)the order of average ag(355)value around the Leizhou Peninsula was east coast(0.503/m)>Qiongzhou Strait(0.502/m)>west coast(0.365/m);(2)the best band combinations of CDOM inversion in spring and autumn were(B4+B11)/B3 and(B7-B1)/B6(B stands for the band of spectral images),and the final inversion results are close to the measured results,indicating that the model has good accuracy;(3)the S_(g)value of the CDOM absorption spectrum was fitted to the hyperbolicexponential model.The fitting accuracy of the model was higher than those of the exponential model and the hyperbolic model,and the best S_(g)inversion model was constructed by selecting Sg(275-295)and Sg(250-295)in spring and autumn;(4)the spatial distributions of ag(355)and S_(g)were inverted,and CDOM in the waters around the Leizhou Peninsula originated from terrestrial organic matter carried by coastal aquaculture zones and runoff in the northeast Zhanjiang and the northern Beibu Gulf. 展开更多
关键词 colored dissolved organic matter(CDOM) ocean and land color instrument(OLCI) spectral slope hyperbolic-exponential model INVERSION
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