ALGORITHM DEVELOPMENT FOR RECOVERING CHLOROPHYLL CONCENTRATIONS IN THE CHESAPEAKE BAY USING AIRCRAFT REMOTE-SENSING, 1989-91

A study using aircraft remote sensing of chlorophyll concentrations wa s conducted in the Chesapeake Bay from 1989 to 1991. The goal was to i mprove spatial and temporal resolution of the distribution of phytopla nkton in this highly dynamic and variable estuary. The focus of the st udy was on improving our ability to estimate chlorophyll a [Chl a] fro m aircraft by developing local algorithms for individual years, and by exploring the use of seasonally and spatially specific algorithms. Ou r findings suggest that an overall, multi-year algorithm can be used p redictively to estimate the distribution of Chl a i.e., the location, duration, and spatial extent of phytoplankton blooms - in near real ti me-. Refinements that improve the recovery of Chl a include the separa tion of spring data from the data for other seasons, and the use of se parate local algorithms for regions of low and high turbidity. These d evelopments improve the accuracy with which we recover Chl a in the Ch esapeake Bay using aircraft remote sensing and have implications for t he detection of changes in algal biomass that are expected to accompan y nutrient reductions between now and the turn of the century. Our res ults suggest that the shipboard sampling of the Monitoring Program may underestimate the biomass of phytoplankton blooms and, hence, the amo unt of particulate carbon produced in the Bay. This finding has ramifi cations for detecting changes in phyloplankton abundance that are expe cted to accompany nutrient reductions, and for processes such as hypox ia (i.e., low oxygen concentrations) that are driven by organic materi al derived from the spring phytoplankton bloom in the mesohaline regio n of the Chesapeake Bay.