Identification mode of chemical oxygen demand in water based on remotely sensing technique and its application

This work was to give an identification mode of chemical oxygen demand (COD) within water body using remotely sensing technique. For this purpose the field data, including the spectral data of water body and the concentration of COD within water ,were collected at Huanjiang river, Rouyuan river and Malian river in Qingyang city , Gansu province of China on 6-7 April and 13-15 October,2006. The 90% samples were employed to establish the identification mode of COD according to Fisher multiclass discriminant rule. By the actual status and the national standard, the concentration of COD were classed three levels. The field spectral data were processed as corresponding bands of Landsat/ TM.. The accuracy reaches 83% with the validation of the rest 10% samples. Further, the model was applied to the two Landsat/ TM images captured on Oct. 16, 2005 and Apr. 10, 2006 in order to obtain the distributing image of COD in the rivers. By mean of the image the temporal change and spatial distribute of the concentration of COD within the three rivers were analyzed. The result shows that the establishment of identification mode based on remotely sensing provides an effective means to obtain rapidly and low-cost the concentration of COD in water environment.