Remote sensing and GIS applications in coastal zone monitoring T. Alexandridis, C. Topaloglou, S. Monachou, G.Tsakoumis, A. Dimitrakos, D. Stavridou Lab of Remote Sensing and GIS School of Agriculture Aristotle University of Thessaloniki
Contents Introduction to materials and instruments: Satellite images, UAV, Spectroradiometer Products (outputs): Land cover maps, habitats maps, macroalgae blooms, Chl-a time series Environmental information: Pressures State Impact Connection to climate change Accolagoons
Introduction Advantages of Remote Sensing Wide coverage Low cost Inaccessible areas Viewing at multiple wavelengths apart from visible Systematic acquisition of data -> time series Availability of historical data
Introduction Limitations Monitoring of certain parameters only Cost effective for medium-large areas Weather conditions (cloud cover, sea surface waves)
Instruments Satellite images ENVISAT MERIS 300m pixel Aqua MODIS 1km pixel Many bands Daily coverage No cost Radiance 12
Instruments Satellite images ALOS AVNIR-2 10m pixel SPOT 5 5-10m pixel
Instruments Satellite images WorldView-2 0.5-2m pixel special coastal blue band
Instruments Low flight image (UAV)
Instruments Spectroradiometer... Records the reflection at 256 discrete wavelengths from blue to near infrared (310-1100 nm)
Instruments...Spectral signatures Spectral signatures Spectral libraries
Methodology From data to information Measured properties: Area Location Intensity Leads to: Object recognition (e.g. land cover) Location of objects (e.g. edges) Estimation of quantity (e.g. Chl-a) Secondary information with geographic analysis
Products: Pressures Land cover Materials: Satellite images Sampling points Remote sensing software Methods: Object-oriented pixel classification Describes: Agricultural areas Settlements Industrial areas
Products: Pressures Temporal changes Materials: Land cover 1994 Land cover 2004 Methods: Change detection with overlay analysis Describes: Changes in pressure Impact Efficiency of measures Loss of wetland vegetation Abandonment of paddy fields
Products: Pressures Mapping aquacultures Materials: Sampling points Satellite images GIS software Methods: Computer assisted photointerpretation Describes: location, area, density of mussel farms long line - pole farms
Products: State Mapping coastal habitats Materials: ALOS AVNIR-2 Satellite image Natura 2000 map Sampling areas Process: Image classification Computer Assisted Photo-interpretation Temporal trends: Habitat changes Landscape metrics
Products: State Mapping coastal habitats
Products: State Mapping marine habitats Materials and instruments: WorldView-2 satellite image RoxAnn echo-sounder In-situ data Process: Results: Digital image enhancement Spectral classification Location and extents of marine habitats Posidonia Oceanica
Products: State Mapping marine habitats Aggelochori site Epanomi site
Products: State Water quality parameters Input data: ΜΟDIS (Terra/Aqua) satellite images MERIS (Envisat) satellite images Methods: Result: Absorption coefficient in 8 bands (blue, green, TIR wavelengths) Neural networks Maps of Chl-a, TSM, SST Time series, video and graphs
Time series of Chl-a (mg/m 3 ) Products: State 10/8/2010 05/11/2010 09/04/2011
Time series of TSM (g/m 3 ) Products: State 10/8/2010 05/11/2010 09/04/2011
Time series of SST ( o C) Products: State 03/8/2010 30/09/2010 06/11/2010
Products: State Mapping macroalgae Satelite images: Worldview- 2, SPOT 4, LANDSAT 5 UAV with spectroradiometer for spectral signatures Robotic airboat with GPS for delineation
Products: State Spectral Signatures Spectral Signatures of Macroalgae in Thermaikos Bay
Mapping macroalgae Products: State Mapping various stages of Ulva spp. bloom Mapping temporal changes of Ulva spp. bloom
Products: State Seasonal water level changes Materials: Sampling points Radar images Methods: Filtering Thresholding σ 0 Describes: Water extents at high and low tide Inundated vegetation
Products: Impact Loss of terrestrial habitats Materials: SPOT 1994 SPOT 2004 Methods: thresholding of NIR band change detection Describes: terrestrial habitats loss due to erosion and low discharge of sediment Legend - '94 Land->Vegetation Vegetation->Water
Discussion Multi-level data integration Data collection Processing Environmental information Field survey Spectroradiometer GPS Spectral signatures Spatial interpolati on Habitats Land cover Remote sensing Telemetry UAV images Time series Satellite images Digital image processing Trend analysis Image photointerpr Landscape metrics Temporal changes Soil-water resources quality Output GDB WebIMS Map
Discussion Connection to climate change Mapping changes over the last 40 years ecosystem degradation (e.g. coral bleaching) morphological changes (e.g. coastline erosion) Prediction modelling spatial dimension to scenarios (e.g. flood risk areas) hazard and risk maps Risk management plans prevention plans (e.g. early warning WebGIS system) emergency response plans (e.g. a Decision Support System) mitigation plans Adaptation strategy
Thank you for your attention Lab of Remote sensing and GIS http://labrsgis.web.auth.gr thalex@agro.auth.gr