Authors: Claudia Giardino Mariano Bresciani Paolo Villa Angiolo Martinelli
Publish Date: 2010/04/13
Volume: 24, Issue: 14, Pages: 3885-3899
Abstract
Satellite multisensor data were used to investigate the evolution in time and space of Lake Trasimeno a shallow and turbid lake in central Italy Largeswath MERIS and MODIS sensors were proposed for regular broad scale monitoring of water quality having compared the retrieved chlorophylla Chla concentration Secchi disk SD depth and surface water temperature with the 2005–2008 timeseries of the in situ data Although in a shorter time span also the MERISderived total suspended matter TSM matched the in situ data MERISderived water quality products confirmed the mesoeutrophic conditions of Lake Trasimeno average Chla = 85 mg/m3 and the low levels of transparency average SD = 1 m A negative correlation found between water levels and Chla suggest the importance of maintaining water levels as close as possible to the hydrometric zero A spatial analysis of TSM also reveals how small tributaries may affect the load of suspended solids in the southern part of the lake Higher spatial resolution satellite images were exploited both to describe land use/cover transformation from 1978 to 2008 and to assess the recent changes in macrophyte colonisation patterns Land cover change detection analysis results showed a decrease in cultivated areas starting from the early Nineties and the subsequent increase in unproductive terrain bare land and pastures and natural woods as well as the changing fragmentation of agricultural areas through time A reduction in macrophyte beds from 2003 to 2008 was also observed We expect the results of this study to support local water authorities in redrawing the management plan of Lake Trasimeno
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