The use of hyperspectral techniques for waters mapping of the Zegrzyńskie Lake

Abstract

The paper presents a possibility of an application of Imaging Spectroscopy to acquire thematic maps of water quality. Thanks to very high spectral, radiometric and spatial resolution of AISA hyperspectral images, which allow to identify zones of water with different properties. An analysis of the spatial distribution of physico-chemical parameters of water was made in 2014 for the Zegrzyńskie Lake. A Hhyperspectral image was acquired by the MGGP Aero aircraft and the Finnish AISA Eagle scanner. Remote sensing indices of water quality (Secchi Disk Depth (SDD), Colored Dissolved Organic Matter (CDOM)) and vegetation index – Carotenoid Reflectance Index 1 (CRI 1), which determines the content of chlorophyll and other plant pigments in the water, was calculated on the image. Based on spatial distribution of water quality indices the IsoData classification was performed. The result was a set of maps with five zones of concentrations of different substances in of the Zegrzyńskie Lake. The verification was made based on in-situ acquired samples of water during airborne data imaging. Due to differences in suspended substances load and different water velocity Bug and Narew water flow in separate streams and mix in the middle of the artificial lake. Following research showed a high correlation between the calculated indices and field measurements. They also confirmed the usability of AISA hyperspectral images to create thematic maps of water quality