Satellite remote sensing of water turbidity in Alqueva reservoir and implications on lake modelling

摘要

The quality control and monitoring of surface freshwaters is crucial, sincesome of these water masses constitute essential renewable water resourcesfor a variety of purposes. In addition, changes in the surface watercomposition may affect the physical properties of lake water, such astemperature, which in turn may impact the interactions of the water surfacewith the lower atmosphere.The use of satellite remote sensing to estimate the water turbidity ofAlqueva reservoir, located in the south of Portugal, is explored. Avalidation study of the satellite derived water leaving spectral reflectanceis firstly presented, using data taken during three field campaigns carriedout during 2010 and early 2011. Secondly, an empirical algorithm to estimatelake water surface turbidity from the combination of in situ and satellitemeasurements is proposed. Finally, the importance of water turbidity on thesurface energy balance is tested in the form of a study of the sensitivityof a lake model to the extinction coefficient of water (estimated fromturbidity), showing that this is an important parameter that affects thelake surface temperature.