LAKE MICHIGAN TIME SERIES PRODUCTIVITY MEASUREMENTS OBTAINED FROM A NEW SEAWIFS AND MODIS SATELLITE RETRIEVAL ALGORITHM*

摘要

A new operational non satellite-specific algorithm for the simultaneous retrieval from satellite data of content of phytoplankton chlorophyll, suspended minerals and dissolved organics in both clear and turbid waters is presented. It contains an array of neural networks providing input for the Levenberg-Marquardt multivariate optimization procedure as the final retrieval tool. With a given accuracy threshold, the developed algorithm is sufficiently robust for data with noise up to 15% for certain hydro-optical conditions. To avoid inadequate retrieval results, the algorithm identifies and eventually discards the pixels with inadequate atmospheric correction and/or water optical properties incompatible with the applied hydro-optical model. The validity of the developed algorithm was tested for Lake Michigan. Two dedicated field campaigns in the vicinity of the Kalamazoo River outfall have been conducted concurrently or quasiconcurrently with satellite overpasses. In addition, some archival shipborne measurements of chl, sm and doc were employed to validate the facility of the algorithm. The conducted comparison of the groundtruth and retrieved data on the water quality parameters in Lake Michigan provides evidence of the algorithm operational efficiency.