Effects of aerosol optical thickness on extracting cyanbacteria bloom

Abstract

In this paper,the effect of Aerosol Optical Thickness(AOT) on cyanbacteria bloom in the Taihu Lake was investigated,which could lay a foundation for dynamically monitoring cyanbacteria bloom.Moreover,a study of the elimination of the effects of AOT on the extraction results was carried out.MODIS products(MOD 02,MOD 04 and MOD 09) were chosen.Single band(NIR) and ratio vegetation index(NIR/G) were used to extract the spatial distribution of cyanbacteria bloom in the Taihu Lake in 2006.The effect of AOT was explored.A quantitative analysis of the degree of the effect of AOT on both the net changes of the area of cyanbacteria bloom and threshold selection was conducted.The results show that the correlation in the case of fixed threshold is higher than that of the demand threshold when the correlation of the area differences of cyanbacteria bloom and AOT is studied with single band and ratio vegetation index.In these two methods,the correlation without atmospheric correction is higher than that with atmospheric correction in the case of the corresponding value.This shows that the atmosphere will have some impact on the extraction of cyanbacteria bloom.Therefore,if cyanbacteria bloom information needs to be extracted accurately and reliably,AOT cannot be ignored.Also,if it cannot be completely eliminated,appropriate methods could be used to minimize its effect.