Authors

Adam Trescott

Publication Date

2-2012

Abstract

We developed empirical remote sensing models to estimate chlorophyll

a concentrations and

cyanobacteria synoptically, over a large inland lake using available Landsat Enhanced Thematic

Mapper Plus (ETM+) data. In contrast to previous studies which rely on the spectral

characteristics of the cyanobacterial specific pigment, phycocyanin, we developed remote

sensing models capable of directly detecting cyanobacterial biovolume. This distinction is

important because Landsat ETM+ data lacks the spectral band information required for optimal

phycocyanin detection. Each model was calibrated and cross-validated with existing

in situ

measurements

from Lake Champlain’s Long-Term Water Quality and Biological Monitoring

Program (LTMP). Lake station measurements taken between 2006 and 2009 were matched with

radiometrically converted exoatmospheric reflectance data from seven spectral bands on the

Landsat ETM+ sensor. Step-wise multi-linear regression indicated data from Landsat ETM+

bands 1, 2 and 3 were most significant for predicting chl-

a and cyanobacteria biovolume. Based

on statistical analysis, the linear models that included visible band ratios slightly outperformed

single band models. The final models captured the extents of cyanobacterial blooms throughout

the 2006-2009 study period. The results serve as an added monitoring tool for resource

managers and present new insight into the initiation and propagation of cyanobacterial blooms in

Lake Champlain.

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