Analytical algorithms for lake water TSM estimation for retrospective analyses of TM and SPOT sensor data

Suspended matter in inland waters is related to total primary production an d fluxes of heavy metals and micropollutants such as PCBs. Synoptic informa tion on suspended matter cannot be obtained from an in situ monitoring netw ork since suspended matter is a spatially inhomogeneous parameter. This pro blem can be solved by the integrated use of remote sensing data, in situ da ta and water quality models. To enable retrospective model and remote sensi ng data comparison of suspended matter concentration and distribution, a me thodology is required for processing satellite images that is independent o f in situ measurements. Analytical optical modelling, based on knowledge of the in situ inherent optical properties, leads to reliable multi-temporal algorithms for estimating suspended matter concentration in lakes for the d ata from the SPOT and Landsat TM sensors. This methodology allows multi-tem poral, multi-site and multi-instrument comparison of TSM maps derived from satellite imagery. This means that satellite sensor data can now become an independent measurement tool for water management authorities. The remote s ensing maps showed that large gradients in TSM were observed for the variou s lakes as well as temporal changes of these spatial gradients. In situ poi nt samples are shown to be not representative for suspended matter in the l akes.