 |
| Titel |
Biogeochemical origins of particles obtained from the inversion of the volume scattering function and spectral absorption in coastal waters |
| VerfasserIn |
X. Zhang, Y. Huot, D. J. Gray, A. Weidemann, W. J. Rhea |
| Medientyp |
Artikel
|
| Sprache |
Englisch
|
| ISSN |
1726-4170
|
| Digitales Dokument |
URL |
| Erschienen |
In: Biogeosciences ; 10, no. 9 ; Nr. 10, no. 9 (2013-09-13), S.6029-6043 |
| Datensatznummer |
250085333
|
| Publikation (Nr.) |
 copernicus.org/bg-10-6029-2013.pdf |
|
|
|
|
|
| Zusammenfassung |
| In the aquatic environment, particles can be broadly separated into
phytoplankton (PHY), non-algal particle (NAP) and dissolved (or very small
particle, VSP) fractions. Typically, absorption spectra are inverted to
quantify these fractions, but volume scattering functions (VSFs) can also be
used. Both absorption spectra and VSFs were used to estimate particle
fractions for an experiment in the Chesapeake Bay. A complete set of water
inherent optical properties was measured using a suite of commercial
instruments and a prototype Multispectral Volume Scattering Meter (MVSM);
the chlorophyll concentration, [Chl] was determined using the HPLC method.
The total scattering coefficient measured by an ac-s and the VSF at a few
backward angles measured by a HydroScat-6 and an ECO-VSF agreed with the
LISST and MVSM data within 5%, thus indicating inter-instrument
consistency. The size distribution and scattering parameters for PHY, NAP
and VSP were inverted from measured VSFs. For the absorption inversion, the
"dissolved" absorption spectra were measured for filtrate passing through
a 0.2 μm filter, whereas [Chl] and NAP absorption spectra were
inverted from the particulate fraction. Even though the total scattering
coefficient showed no correlation with [Chl], estimates of [Chl] from the
VSF-inversion agreed well with the HPLC measurements (r = 0.68, mean
relative errors = −20%). The scattering associated with NAP and VSP
both correlated well with the NAP and "dissolved" absorption coefficients,
respectively. While NAP dominated forward, and hence total, scattering, our
results also suggest that the scattering by VSP was far from negligible and
dominated backscattering. Since the sizes of VSP range from 0.02 to 0.2 μm, covering (a portion of) the operationally defined "dissolved"
matter, the typical assumption that colored dissolved organic matter (i.e.,
CDOM) does not scatter may not hold, particularly in a coastal or estuarine
environment. |
| |
|
| Teil von |
|
|
|
|
|
|
|
|