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MERIS images for Doñana marshlands monitoring

Ricardo Díaz-Delgado(1), Javier Bustamante(1), David Aragonés(1) and José Antonio Domínguez(2)

(1) Doñana Biological Station (CSIC), Avda. Maria Luisa s/n, 41013, Seville, Spain
(2) Centre for Hydrographic Studies, Centre for Hydrographic Studies, 28005 Madrid, Spain

Abstract

Doñana shallow marshes extend over 270 km2 across the mouth of the Guadalquivir River (SW Spain) being the largest wetlands in Western Europe. Doñana marshlands hold a high diversity on waterfowl being a critical stopover for migratory birds. Inundation takes place periodically in a natural way mainly driven by rainfall (average per year 560 mm). Consequently, humid years marshland becomes flooded as an unique water body, while dry and medium years marshland appears fragmented in countless wetlands. Severe human transformations have led to a dramatic reduction of marshland extent, including channelling of river branches, periodic river course dredges, wetlands conversion to intensive crops and fisheries, aquifer overexploitation, water pollution episodes, permanent waterway transport, etc. These changes make essential reconstruct historical changes on inundated area in a year by year basis in order to help in restoration programs. The Remote Sensing Laboratory of Doñana Biological Station is conducting such reconstruction and monitoring current changes by using a long time series of Landsat images from MSS, TM and ETM+ sensors. Such approach has helped to produce about 300 inundation masks enabling to reproduce hydroperiod along a whole flooding regime (September to August). Moreover, water turbidity and depth have been systematically mapped as well as presence of alien species. However, Landsat 5 TM acquisitions stopped suddenly last October 2007, what raises the question on Landsat mission continuity. The work presented here address the utility of MERIS images to produce reliable inundation maps of Doñana marshlands and check the ability to discriminate turbidity, chlorophyll and depth gradients of shallow water bodies, in spite of its lower spatial resolution but seizing the better spectral resolution. According to the results MERIS images may be systematically employed to monitor seasonal changes and trends on inundation of Doñana marshlands.

 

Keywords: ESA European Space Agency - Agence spatiale europeenne, observation de la terre, earth observation, satellite remote sensing, teledetection, geophysique, altimetrie, radar, chimique atmospherique, geophysics, altimetry, radar, atmospheric chemistry