Comparison of shipboard and satellite measurements of surface water temperature and chlorophyll a in Lake Ontario

摘要

The binational Lake Ontario Lower Aquatic Foodweb Assessment program (LOLA) intensively sampled Lake Ontario in the Spring (April 28-May 3), Summer (August 10-11 and August 19-21) and Fall (September 21-25) of 2003. However, the timing of shipboard surveys often misses critical periods in biological productivity. We directly compared surface water temperature and chlorophyll a (chl a) measurements made during these cruises to Moderate Resolution Imaging Spectroradiometer (MODIS) satellite images for May 3, August 18, and September 21, 2003. Satellite measurements were strongly correlated to shipboard measurements for surface water temperature (r~2 = 0.98) and chl a (r~2 = 0.62, offshore sites only). The OC4 algorithm for chl a greatly overestimated nearshore sites because of the probable presence of color producing agents other than chl a. However, its relative reliability for offshore sites adds confidence in using the imagery to fill the gaps between sampling cruises.