Calculation of UV attenuation and colored dissolved organic matter absorption spectra from measurements of ocean color

Johannessen, Sophia C.; Miller, William L.; Cullen, John J.

doi:10.1029/2000jc000514

Cited by 74 publications

(69 citation statements)

References 57 publications

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“…Guo et al (2007) have observed a strong linear and inverse relationship of salinity and a CDOM in surface waters of the Yangtze River (YR) estuary in the ECS. This relationship appears to be consistent with various previous studies in other regions (Jerlov, 1968;Monahan and Pybus, 1978;Boss et al, 2001;Bowers et al, 2000Bowers et al, , 2004Binding and Bowers, 2003;Moon et al, 2006). A similar relationship together with the a CDOM -reflectance ratio relationship can therefore provide reliable estimates of salinity and CDOM in the focused YR estuary areas of the ECS using satellite ocean colour observations.…”

Section: Introductionsupporting

confidence: 82%

“…Coloured or chromophoric dissolved organic matter (CDOM), historically described as gelbstoff or yellow substance, is the main pool of absorbing substances in water and also plays a major role in various physical, chemical and biological processes (Johannessen et al, 2003;Twardowski et al, 2004). Coastal and estuary areas typically have higher and more variable abundances of these materials which originate primarily from humic substances of terrestrial origin transported to coastal seas through rivers and runoff from the land (Chester, 1990;Nelson et al, 2007).…”

Section: Introductionmentioning

confidence: 99%

“…Such LSW plume regions can be explicitly inferred from field measurements or satellite observations of coloured dissolved organic matter and salinity and can be used to study the physical, chemical and biological states of the water column (Jerlov, 1968;O'Reilly et al, 1998;Boss et al, 2001;Kahru and Mitchell, 2001; Published by Copernicus Publications on behalf of the European Geosciences Union. 2020 Y. H. Ahn et al: Satellite remote sensing of a low-salinity water plume in the East China Sea Siegel et al, 2002;Johannessen et al, 2003;Bowers et al, 2004;Morel et al, 2007;Nelson et al, 2007).…”

Section: Introductionmentioning

confidence: 99%

“…Interpretation of remotely sensed ocean colour has thus largely depended on the ability to establish relationships between the apparent optical properties (remote sensing reflectance R r ) and inherent optical properties (CDOM) (e.g. Kahru and Mitchell, 2001;Siegel et al, 2002;Johannessen et al, 2003;Bowers et al, 2004;Kowalczuk et al, 2005;Kutser et al, 2005;Doxaran et al, 2005;Moon et al, 2007). Several of these studies have confirmed by theory and measurements the existence of a tight relationship between the ratio of reflection coefficients, particularly in the blue-green part of the spectrum, and CDOM absorption (a CDOM ), and this relationship has been found to be robust and applicable to a range of water bodies in which the CDOM is present in concentrations sufficient to effect the water colour in the blue spectrum.…”

Section: Introductionmentioning

confidence: 99%

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Satellite remote sensing of a low-salinity water plume in the East China Sea

et al. 2008

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Abstract.With the aim to map and monitor a low-salinity water (LSW) plume in the East China Sea (ECS), we developed more robust and proper regional algorithms from large in-situ measurements of apparent and inherent optical properties (i.e. remote sensing reflectance, R rs , and absorption coefficient of coloured dissolved organic matter, a CDOM ) determined in ECS and neighboring waters. Using the above data sets, we derived the following relationships between visible R rs and absorption by CDOM, i.e. R rs (412)/R rs (555) vs. a CDOM (400) (m −1 ) and a CDOM (412) (m −1 ) with a correlation coefficient R 2 0.67 greater than those noted for R rs (443)/R rs (555) and R rs (490)/R rs (555) vs. a CDOM (400) (m −1 ) and a CDOM (412) (m −1 ). Determination of a CDOM (m −1 ) at 400 nm and 412 nm is particularly necessary to describe its absorption as a function of wavelength λ using a single exponential model in which the spectral slope S as a proxy for CDOM composition is estimated by the ratio of a CDOM at 412 nm and 400 nm and the reference is explained simply by a CDOM at 412 nm. In order to derive salinity from the absorption coefficient of CDOM, in-situ measurements of salinity made in a wide range of water types from dense oceanic to light estuarine/coastal systems were used along with in-situ measurements of a CDOM at 400 nm, 412 nm, 443 nm and 490 nm. The CDOM absorption at 400 nm was better inversely correlated (R 2 =0.86) with salinity than at 412 nm, 443 nm and 490 nm (R 2 =0.85-0.66), and this correlation corresponded best with an exponential (R 2 =0.98) rather than a linear function of salinity measured in a variety of water types from this and other regions. Validation against a discrete in-situ data set showed that empirical algorithms derived from the above relationships could be successfully applied to satellite data over the range of water types for which they have been developed. Thus, we applied these algorithms to a series of SeaWiFS images for the derivation Correspondence to: P. Shanmugam (pshanmugam90@hotmail.com) of CDOM and salinity in the context of operational mapping and monitoring of the springtime evolution of LSW plume in the ECS. The results were very encouraging and showed interesting features in surface CDOM and salinity fields in the vicinity of the Yangtze River estuary and its offshore domains, when a regional atmospheric correction (SSMM) was employed instead of the standard (global) SeaWiFS algorithm (SAC) which revealed large errors around the edges of clouds/aerosols while masking out the nearshore areas. Nevertheless, there was good consistency between these two atmospheric correction algorithms over the relatively clear regions with a mean difference of 0.009 in a CDOM (400) (m −1 ) and 0.096 in salinity (psu). This study suggests the possible utilization of satellite remote sensing to assess CDOM and salinity and thus provides great potential in advancing our knowledge of the shelf-slope evolution and migration of the LSW plume properties in the ECS.

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Section: Introductionsupporting

confidence: 82%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Satellite remote sensing of a low-salinity water plume in the East China Sea

et al. 2008

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“…CDOM absorption spectra were corrected for instrument drift, fine particle scattering, and the difference between refractive indices for Milli-Q and estuarine and seawater using the following equation (Johannessen et al, 2003):…”

Section: Absorbance Fluorescence and Doc Measurementsmentioning

confidence: 99%

Photochemical production of hydrogen peroxide and methylhydroperoxide in coastal waters

et al. 2005

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Pulsed, cross‐shelf export of terrigenous dissolved organic carbon to the Gulf of Mexico

2014

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The export of terrigenous dissolved organic carbon (tDOC) and other river-borne material across the continental shelf boundary has important ramifications for biological productivity and the cycling of continentally derived bioelements in the ocean. Recent studies revealed the 275-295 nm spectral slope coefficient of chromophoric dissolved organic matter (CDOM), S 275-295 , is a reliable tracer for terrigenous dissolved organic carbon (tDOC) in river-influenced ocean margins. Here an empirical algorithm for the accurate retrieval of S 275-295 from ocean color was developed and validated using in situ optical properties collected seasonally in the northern Gulf of Mexico. This study also demonstrated S 275-295 is a robust proxy for tDOC concentration in this environment, thereby providing a means to derive surface tDOC concentrations on synoptic scales and in quasi-real time using remote sensing. The resulting tDOC-algorithm was implemented using Aqua-MODIS in a retrospective analysis of surface tDOC concentrations over the northern Gulf of Mexico between July 2002 and June 2013. Large pulses of tDOC were observed in continentalslope surface waters off the Mississippi River delta, indicating cross-shelf export of tDOC was sporadic and exhibited considerable interannual variability. Favorable winds following an anomalously high discharge from the Mississippi-Atchafalaya river system always coincided with a major export event, and in general, cross-shelf export was enhanced during years of anomalously high discharge. The tDOC-algorithm will find applicability in the assessment of future climate-and human-induced changes in tDOC export, in biogeochemical models of the continental shelf, and in the validation of high-resolution coastal models of buoyancy-driven shelf circulation.

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Calculation of UV attenuation and colored dissolved organic matter absorption spectra from measurements of ocean color

Cited by 74 publications

References 57 publications

Satellite remote sensing of a low-salinity water plume in the East China Sea

Satellite remote sensing of a low-salinity water plume in the East China Sea

Photochemical production of hydrogen peroxide and methylhydroperoxide in coastal waters

Pulsed, cross‐shelf export of terrigenous dissolved organic carbon to the Gulf of Mexico

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