Particulate and dissolved spectral absorption on the continental shelf of the southeastern United States

Nelson, James R.; Guarda, Sonia

doi:10.1029/95jc00222

Cited by 87 publications

(70 citation statements)

References 46 publications

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“…Advection and diffusion by the background flow further modulates the distribution of CDOM absorption. There may also be an additional in-water source of CDOM associated with phytoplankton [Twardowski, 1998], which we did not observe in our data, though it may contribute to the different a a -s relationship observed farther downstream at the South Atlantic Bight [Nelson and Guarda, 1995]. This sink/source layout results in a spatial distribution of CDOM, which is decreasing away from shore (with increase in salinity) and increasing with depth at the shelf (also with increase in salinity).…”

Section: Resultscontrasting

confidence: 53%

Spatial and temporal variability of absorption by dissolved material at a continental shelf

Boss¹,

Pegau²,

Zaneveld³

et al. 2001

J. Geophys. Res.

121

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Abstract. Optical properties of dissolved (colored dissolved organic material (CDOM)) and particulate matter and hydrographic measurements were obtained at the Mid-Atlantic Bight during the fall of 1996 and the spring of 1997 as part of the Coastal Mixing and Optics experiment. To assess the temporal and spatial variability, time series were obtained at one location and cross-shelf transects were carried out. On short timescales, variability in the vertical distribution of the dissolved fraction was mostly due to highfrequency internal waves. This variability was conservative, resulting in no changes on isopycnals. Over longer periods and episodically, CDOM variability was dominated by storms. The storms were associated with sediment resuspension events and were accompanied by an increase in the absorption by the dissolved materials. Data from spatial transects show that near the bottom, over the shelf, and in both spring and fall, increased particulate absorption and increased CDOM absorption co-occur. These data support the hypothesis that bottom sediments can act as a source of dissolved organic carbon during sediment resuspension events.

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Section: Resultscontrasting

confidence: 53%

Spatial and temporal variability of absorption by dissolved material at a continental shelf

Boss¹,

Pegau²,

Zaneveld³

et al. 2001

J. Geophys. Res.

121

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show abstract

“…Figure 4 shows the two parameters plotted against each other and the apparent inverse relationship. A similar relationship was also seen between a and S. Inverse * 375 relationships between a 375 and S in marine waters have been reported before in the literature (Green 1992;Blough et al 1993;Nelson and Guarda 1995;Vodacek et al 1997; among others). However, care must be taken when studying the behavior of S in natural waters, as it is highly sensitive to the wavelength range over which it is estimated.…”

Section: ϫ64a375supporting

confidence: 62%

The optics of chromophoric dissolved organic matter (CDOM) in the Greenland Sea: An algorithm for differentiation between marine and terrestrially derived organic matter

Stedmon¹,

Markager²

2001

Limnology & Oceanography

194

156

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The optics of chromophoric dissolved organic matter (CDOM) in the Greenland Sea were investigated and compared to results from earlier studies in the Southeastern North Sea. Absorption at 375 nm (a375) in the Greenland Sea varied from 0.77 m−1 to the detection limit of our instrument (0.05 m−1), with the highest values found during summer. The spectral slope coefficient (S) ranged from 8.2 to 26.4 µm−1 with the highest values occurring during winter. Seasonal variations in the in situ production and degradation of CDOM where shown to be responsible for the trends seen. A negative correlation between S and a375 was evident in the Greenland Sea and differed noticeably from that found in coastal waters. The differing S‐a375 behavior of CDOM known to be of terrestrial origin allowed the development of an algorithm for the differentiation between marine and terrestrial organic matter. The behavior of marine CDOM was modeled by S = 7.4 + 1.1/a375.

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“…As a consequence of its fresh water origin and conservative behavior, CDOM absorption in coastal seas has been previously observed to be inversely correlated with salinity in the same way, and therefore has been considered a good indicator of salinity in various regions (e.g. Jerlov, 1968;Nelson and Guarda, 1995;Boss et al, 2001;Binding and Bowers, 2003;Kwalczuk et al, 2005;Moon et al, 2006;Guo et al, 2007;Sasaki et al, 2008). Findings from the above relationships of salinity and a CDOM (λ) revealed that salinity seemed to be better correlated with a CDOM at 400 nm than a CDOM at other longer wavelengths, and therefore a CDOM at 400 nm could be used as a proxy for salinity in this region.…”

Section: Spectral Variations Of Cdommentioning

confidence: 99%

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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Particulate and dissolved spectral absorption on the continental shelf of the southeastern United States

Cited by 87 publications

References 46 publications

Spatial and temporal variability of absorption by dissolved material at a continental shelf

Spatial and temporal variability of absorption by dissolved material at a continental shelf

The optics of chromophoric dissolved organic matter (CDOM) in the Greenland Sea: An algorithm for differentiation between marine and terrestrially derived organic matter

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

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