Operatinal monitoring of suspended matter distribution using modis images and numerical modelling
Abstract
Coastal sea is primary receiver of suspended matter from rivers and other land-based sources. Considerable amount of suspended matter is released to coastal waters during harbour dredging. As a result, transparency of the coastal waters decreases, less solar radiation reaches marine biota in euthopic zone and intensity of photosynthesis declines. Eventually this may result in sharp gradients of biogeochemical parameters between coastal and open sea. In that respect high spatial resolution operational tools are necessary to monitor the transport of suspended matter in the coastal sea and mass exchange with open sea. MODIS images of remote sensing reflectance of 250 m resolution and high resolution (125x125 m) hydrodynamic model based on nonlinear shallow-water equations linked with particle transport model were used to monitor the transport of suspended matter during Paldiski South Harbour dredging, Pakri Bay, the southern Gulf of Finland. Remote sensing data consisted of MODIS images from band 1 (620- 670 nm) and band 2 (841-876 nm). Several surveys of water transparency, concentration of suspended matter and spectrometrical beam attenuation coefficient were performed during dredging. That allowed to estimate linear relationship between remote sensing reflectance at band 1 and in situ suspended matter concentration. The estimated corelation coefficient was 0.73 (with spectrometrical beam attenuation coefficient 0.75). This case study shows that MODIS images provide frequent (twice per day) and near-real time detailed maps of water turbidity distribution in cloud free conditions. Model results that were continuously validated using in situ measurements of water transparency and MODIS images of remote sensing reflectance, provide information on suspended matter distribution when satellite images are not available.
- Publication:
-
35th COSPAR Scientific Assembly
- Pub Date:
- 2004
- Bibcode:
- 2004cosp...35.1423S