Modification and validation of a quasi-analytical algorithm for inherent optical properties in the turbid waters of Poyang Lake, China

2014 ◽  
Vol 8 (1) ◽  
pp. 083643 ◽  
Author(s):  
Jue Huang ◽  
Liqiong Chen ◽  
Xiaoling Chen ◽  
Liqiao Tian ◽  
Lian Feng ◽  
...  
2019 ◽  
Vol 69 (8) ◽  
pp. 925-937
Author(s):  
Kumaraswami Munnooru ◽  
Sisir Kumar Dash ◽  
Gijjapu Durga Rao ◽  
Ramu Karri ◽  
Vinjamuri Ranga Rao

Author(s):  
Wiwin Ambarwulan ◽  
Widiatmaka ◽  
Syarif Budhiman

The  paper  describes inherent optical properties  (IOP)  of  the  Berau  coastal  waters  derived from in  situ measurements  and Medium  Resolution  Imaging  Spectrometer  (MERIS) satellite  data. Field  measurements  of optical  water,  total  suspended  matter  (TSM), and  chlorophyll-a  (Chl-a) concentrations were carried out during the dry season of 2007. During this periode, only four MERISdata were  coincided with in  situ measurements on 31 August  2007. The MERIS  top-of-atmosphere radiances were atmospherically corrected using the MODTRAN radiative transfer model. The in situ optical  measurement  have  been  processed  into apparent optical properties  (AOP) and sub  surface irradiance. The remote sensing reflectance of in situ measurement as well as MERIS data were inverted into  the  IOP  using quasi-analytical algorithm  (QAA).  The  result  indicated  that coefficient  of determination (R 2) of backscattering coefficients of suspended particles (bbp) increased with increasing wavelength,  however  the  R2 of  absorption  spectra  of  phytoplankton  (aph)  decreased  with  increasing wavelength.


2011 ◽  
Vol 8 (1) ◽  
pp. 85-111 ◽  
Author(s):  
F. Mélin

Abstract. Time series of inherent optical properties (IOPs) derived from SeaWiFS and MODIS are compared for the Adriatic Sea. The IOPs are outputs of the Quasi-Analytical Algorithm and include total absorption a, phytoplankton absorption aph, absorption associated with colored detrital material (CDM) acdm, and particle backscattering coefficient bbp. The average root-mean square difference Δ computed for log-transformed distributions decreases for a from 0.084 at 412 nm to 0.052 at 490 nm, is higher for aph(443) (0.149) than for acdm(443) (0.071), and is approximately 0.165 for bbp at various wavelengths. The SeaWiFS a at 443 and 490 nm, aph at 443 nm and bbp are on average higher than the MODIS counterparts. Statistics show significant variations in space and time. There is an overall increasing gradient for Δ associated with the absorption terms from the open Southern and Central Adriatic to the northwest part of the basin, and a reversed gradient for the particulate backscattering coefficient. Only a(412) and acdm(443) currently represent an unbiased continuity bridging the SeaWiFS and MODIS periods for the Adriatic Sea.


2013 ◽  
Vol 3 (1) ◽  
pp. 325-337
Author(s):  
S. P. Tiwari ◽  
P. Shanmugam ◽  
Y. H. Ahn ◽  
J. H. Ryu

Accurate modeling of spectral remote sensing reflectance (Rrs) is of great interest for ocean colour studies in highly turbid and relatively clear waters. In this work a semianalytical model that simulates the spectral curves of remote sensing reflectance of these waters is developed based on the inherent optical properties (IOPs) and f and Q factors. For accommodating differences in the optical properties of the water and accounting for their directional variations, IOPs and f and Q  factors are derived as a function of phytoplankton pigments, suspended sediments and solar zenith angle. Results of this model are compared with in-situ bio-optical data collected at 83 stations encompassing highly turbid/relatively cleared waters of the South Sea of Korea. Measured and modeled remote sensing reflectances agree favorably in both magnitude and spectral shape, with considerably low errors (mean relative error MRE -0.0327; root mean square error RMSE 0.205, bias -0.0727 and slope 1.15 and correlation coefficient R2 0.74). These results suggest that the new model has the ability to reproduce measured reflectance values and has potentially profound implications for remote sensing of complex waters in this region.


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