Spectral slopes of the absorption coefficient of colored dissolved and detrital material inverted from UV‐visible remote sensing reflectance

Wei, Jianwei; Lee, Zhongping; Ondrusek, Michael; Mannino, Antonio; Tzortziou, M.; Armstrong, Roy A.

doi:10.1002/2015jc011415

Cited by 26 publications

(11 citation statements)

References 74 publications

(132 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…It should be emphasized that more information on S R versus a CDOM (440) relationships for different water types is a prerequisite for development of algorithms for accurate retrieval of CDOM absorption and photobleaching from space. Unfortunately, so far there is no operational satellite color sensor with spectral absorption lower than 412 nm available for monitoring the upper layer of the ocean [27], but efforts are being made to include UV wavelengths in the next generation of ocean color sensors [24,27]. Also, for analysis of historical ocean color data for different water bodies, improved knowledge on CDOM absorption characteristics is vital, since site specific S plots can be used to extrapolate satellite retrieved CDOM absorption into the UV spectral region.…”

Section: S 280−295 / S 350−400 Ratios Used As Indicators Of Cdom Photmentioning

confidence: 99%

See 1 more Smart Citation

CDOM Absorption Properties of Natural Water Bodies along Extreme Environmental Gradients

Nima

Frette

Hamre

et al. 2019

Water

View full text Add to dashboard Cite

We present absorption properties of colored dissolved organic matter (CDOM) sampled in six different water bodies along extreme altitudinal, latitudinal, and trophic state gradients. Three sites are in Norway: the mesotrophic Lysefjord (LF), Samnangerfjord (SF), and Røst Coastal Water (RCW); two sites are in China: the oligotrophic Lake Namtso (LN) and the eutrophic Bohai Sea (BS); and one site is in Uganda: the eutrophic Lake Victoria (LV). The site locations ranged from equatorial to subarctic regions, and they included water types from oligotrophic to eutrophic and altitudes from 0 m to 4700 m. The mean CDOM absorption coefficients at 440 nm [ a CDOM ( 440 ) ] and 320 nm [ a CDOM ( 320 ) ] varied in the ranges 0.063–0.35 m − 1 and 0.34–2.28 m − 1 , respectively, with highest values in LV, Uganda and the lowest in the high-altitude LN, Tibet. The mean spectral slopes S 280 − 500 and S 350 − 500 were found to vary in the ranges of 0.017–0.032 nm − 1 and 0.013–0.015 nm − 1 , respectively. The highest mean value for S 280 − 500 as well as the lowest mean value for S 350 − 500 were found in LN. Scatter plots of S 280 − 500 versus a CDOM ( 440 ) and a CDOM ( 320 ) values ranges revealed a close connection between RCW, LF, and SF on one side, and BS and LV on the other side. CDOM seems to originate from terrestrial sources in LF, SF, BS, and LV, while RCW is characterized by autochthonous-oceanic CDOM, and LN by autochthonous CDOM. Photobleaching of CDOM is prominent in LN, demonstrated by absorption towards lower wavelengths in the UV spectrum. We conclude that high altitudes, implying high levels of UV radiation and oligotrophic water conditions are most important for making a significant change in CDOM absorption properties.

show abstract

Section: S 280−295 / S 350−400 Ratios Used As Indicators Of Cdom Photmentioning

confidence: 99%

“…The absorption spectral slope S of CDOM can be used as an indicator to characterize CDOM in natural water bodies and to reveal their origin [25][26][27]. In general, S values are found to be higher in open oceanic water than in fresh water or coastal water [28].…”

Section: Introductionmentioning

confidence: 99%

CDOM Absorption Properties of Natural Water Bodies along Extreme Environmental Gradients

Nima

Frette

Hamre

et al. 2019

Water

View full text Add to dashboard Cite

show abstract

“…For an improvement in the reconstruction method, extreme cases such as R rs data from blooming waters should be included to further optimize the parameterization. It is also worthwhile to expand the spectral range of reconstruction from 400–700 nm to 350–800 nm including consideration for the atmospheric corrections and inversion algorithms of Chl‐ a and CDOM (IOCCG, ; Wei et al, ).…”

Section: Discussionmentioning

confidence: 99%

A Reconstruction Method for Hyperspectral Remote Sensing Reflectance in the Visible Domain and Applications

Sun

Qiu

et al. 2018

JGR Oceans

View full text Add to dashboard Cite

A reconstruction method was developed for hyperspectral remote sensing reflectance (Rrs) data in the visible domain (400–700 nm) based on in situ observations. A total of 2,647 Rrs spectra were collected over a wide variety of water environments including open ocean, coastal and inland waters. Ten schemes with different band numbers (6 to 15) were tested based on a nonlinear model. It was found that the accuracy of the reconstruction increased with the increase of input band numbers. Eight of these schemes met the accuracy criterion with the mean absolute error (MAE) and mean relative error (MRE) values between reconstructed and in situ Rrs less than 0.00025 sr−1 and 5%, respectively. We chose the eight‐band scheme for further evaluation because of its decent performance. The results revealed that the parameterization derived by the eight‐band scheme was efficient for restoring Rrs spectra from different water bodies. In contrast to the previous studies that used a linear model with 15 spectral bands, the nonlinear model with the eight‐band scheme yielded a comparable reconstruction performance. The MAE and MRE values were generally less than 0.00016 sr−1 and 3% respectively; much lower than the uncertainties in satellite‐derived Rrs products. Furthermore, a preliminary experiment of this method on the data from the Hyperspectral Imager for the Coastal Ocean (HICO) showed high potential in the future applications for reconstructing Rrs spectra from space‐borne optical sensors. Overall, the eight‐band scheme with our nonlinear model was proven to be optimal for hyperspectral Rrs reconstruction in the visible domain.

show abstract

“…The R rs spectra were synthesized with a database of inherent optical properties (IOP) presented in the International Ocean Color Coordinating Group report [ IOCCG , ]. The synthetic IOP data cover a wide range of aquatic environments and have been extensively used for model development and validation [ Chen et al ., ; Salama and Stein , ; Wang et al ., ; Wei and Lee , ; Wei et al ., ]. The remote‐sensing reflectance was simulated by Hydrolight 5.1 [ Mobley and Sundman , ].…”

Section: Evaluation Of the Qa Systemmentioning

confidence: 99%

A system to measure the data quality of spectral remote sensing reflectance of aquatic environments

Wei

Lee

Shang

2016

J. Geophys. Res. Oceans

Self Cite

View full text Add to dashboard Cite

Spectral remote‐sensing reflectance (Rrs, sr−1) is the key for ocean color retrieval of water bio‐optical properties. Since Rrs from in situ and satellite systems are subject to errors or artifacts, assessment of the quality of Rrs data is critical. From a large collection of high quality in situ hyperspectral Rrs data sets, we developed a novel quality assurance (QA) system that can be used to objectively evaluate the quality of an individual Rrs spectrum. This QA scheme consists of a unique Rrs spectral reference and a score metric. The reference system includes Rrs spectra of 23 optical water types ranging from purple blue to yellow waters, with an upper and a lower bound defined for each water type. The scoring system is to compare any target Rrs spectrum with the reference and a score between 0 and 1 will be assigned to the target spectrum, with 1 for perfect Rrs spectrum and 0 for unusable Rrs spectrum. The effectiveness of this QA system is evaluated with both synthetic and in situ Rrs spectra and it is found to be robust. Further testing is performed with the NOMAD data set as well as with satellite Rrs over coastal and oceanic waters, where questionable or likely erroneous Rrs spectra are shown to be well identifiable with this QA system. Our results suggest that applications of this QA system to in situ data sets can improve the development and validation of bio‐optical algorithms and its application to ocean color satellite data can improve the short‐term and long‐term products by objectively excluding questionable Rrs data.

show abstract

Spectral slopes of the absorption coefficient of colored dissolved and detrital material inverted from UV‐visible remote sensing reflectance

Cited by 26 publications

References 74 publications

CDOM Absorption Properties of Natural Water Bodies along Extreme Environmental Gradients

CDOM Absorption Properties of Natural Water Bodies along Extreme Environmental Gradients

A Reconstruction Method for Hyperspectral Remote Sensing Reflectance in the Visible Domain and Applications

A system to measure the data quality of spectral remote sensing reflectance of aquatic environments

Contact Info

Product

Resources

About