Abstract
The objective of this research is to examine the possibility of water quality monitor in Lake Koyama-ike, Tottori Prefecture, just after brackishing lake water on March 12, 2012. Authors discussed about the relationship between the relationship between spectral reflectance and water quality (Chla: Chlorophyll-a) in the lake based on the field survey of 3 time in 2012. As a result, the following matters became clear. First, the the spectral-reflectance characteristic was shown as that of typical eutrophic water area. Next, the optimal model for Chla estimation in the lake by remote sensing technique was "reflectance ratio between 672 nm (±about 5 nm) and 704 nm (±about 5 nm). Moreover, the significant correlation between "the reflectance ratio between 659 nm (red band) and 724 nm (rededge) of WorldView-2 satellite" and "Chla" was obserbed. Although it was very difficult toestimate Chla in the lake from the results using a simple reflectance ratio model in the present satellite, when using hyper-spectral (HS) sensor which is due to be launched in the near future, Chla estimation in the lake was possible.
