Characterizing lateral variability of phytoplankton chlorophyll in Chesapeake Bay with aircraft ocean color data

Abstract

The aim of this study was to characterize the small-scale variability (100s of meters to kilometers) of phytoplankton chlorophyll along cross-bay (lateral) flight tracks located in mid- and lower Chesapeake Bay over weekly, seasonal and interannual scales. Analyses were made on aircraft ocean color data collected in 1990 and 1991 by NASA's Ocean Data Acquisition System (ODAS). Lateral variability was highest during the spring bloom events of 1990 and was typically expressed as high west-low east gradients, particularly in the lower bay where up to 6-fold decreases in surface chlorophyll were found along a 15 km track. There was no spring bloom in 1991, which resulted in low lateral variability throughout the bay. These gradients appear to be associated with water masses that differ both physically and chemically along lateral transects. In the lower bay, phytoplankton patch size was within the resolution of future satellite sensors, which will provide even greater temporal coverage of the bay than that provided by aircraft.