Due to spatial and temporal variability an effective monitoring system for water resources must consider the use of remote sensing to provide information.Synthetic Aperture Radar(SAR)is useful due to timely data acqui...Due to spatial and temporal variability an effective monitoring system for water resources must consider the use of remote sensing to provide information.Synthetic Aperture Radar(SAR)is useful due to timely data acquisition and sensitivity to surface water and flooded vegetation.The ability to map flooded vegetation is attributed to the double bounce scattering mechanism,often dominant for this target.Dong Ting Lake in China is an ideal site for evaluating SAR data for this application due to annual flooding caused by mountain snow melt causing extensive changes in flooded vegetation.A curvelet-based approach for change detection in SAR imagery works well as it highlights the change and suppresses the speckle noise.This paper addresses the extension of this change detection technique to polarimetric SAR data for monitoring surface water and flooded vegetation.RADARSAT-2 images of Dong Ting Lake demonstrate this curvelet-based change detection technique applied to wetlands although it is applicable to other land covers and for post disaster impact assessment.These tools are important to Digital Earth for map updating and revision.展开更多
A methodology is presented for estimating percent coverage of impervious surface(IS)and forest cover(FC)within Landsat thematic mapper(TM)pixels of urban areas.High-resolution multi-spectral images from Quickbird(QB)p...A methodology is presented for estimating percent coverage of impervious surface(IS)and forest cover(FC)within Landsat thematic mapper(TM)pixels of urban areas.High-resolution multi-spectral images from Quickbird(QB)play a key role in the sub-pixel mapping process by providing information on the spatial distributions of ISs and FCs at 2.4 m ground sampling intervals.Thematic classifications,also derived from the Landsat imagery,have then been employed to define relationships between 30 m Landsat-derived greenness values and percent IS and FC.By also utilizing land cover/land use classification derived from Landsat and defining unique relationships for urban sub-classes(i.e.residential,commercial/industrial,open land),confusion between impervious and fallow agricultural lands has been overcome.Test results are presented for Ottawa-Gatineau,an urban area that encompasses many aspects typical of the North American urban landscape.Multiple QB scenes have been acquired for this urban centre,thereby allowing us to undertake an in-depth study of the error budgets associated with the fractional inference process.展开更多
基金funded by the Bayern-Pfalz-Foundation in Munich(Germany)and the German Academic Exchange Service(DAAD).The Remote Sensing Science(RSS)program at CCRS also supported this research project.The authors would like to thank both organizations for their financial and administrative support.The RADARSAT-2 data were acquired under the Capacity Building Centre for Earth Observation(CBCEO)agreement between the Chinese Academy of Sciences(CAS)and Earth Science Sector(ESS).ESS Contribution number/Nume´ro de contribution du SST:20100490.
文摘Due to spatial and temporal variability an effective monitoring system for water resources must consider the use of remote sensing to provide information.Synthetic Aperture Radar(SAR)is useful due to timely data acquisition and sensitivity to surface water and flooded vegetation.The ability to map flooded vegetation is attributed to the double bounce scattering mechanism,often dominant for this target.Dong Ting Lake in China is an ideal site for evaluating SAR data for this application due to annual flooding caused by mountain snow melt causing extensive changes in flooded vegetation.A curvelet-based approach for change detection in SAR imagery works well as it highlights the change and suppresses the speckle noise.This paper addresses the extension of this change detection technique to polarimetric SAR data for monitoring surface water and flooded vegetation.RADARSAT-2 images of Dong Ting Lake demonstrate this curvelet-based change detection technique applied to wetlands although it is applicable to other land covers and for post disaster impact assessment.These tools are important to Digital Earth for map updating and revision.
基金This work was supported partially by Canadian Space Agency GRIP funding.
文摘A methodology is presented for estimating percent coverage of impervious surface(IS)and forest cover(FC)within Landsat thematic mapper(TM)pixels of urban areas.High-resolution multi-spectral images from Quickbird(QB)play a key role in the sub-pixel mapping process by providing information on the spatial distributions of ISs and FCs at 2.4 m ground sampling intervals.Thematic classifications,also derived from the Landsat imagery,have then been employed to define relationships between 30 m Landsat-derived greenness values and percent IS and FC.By also utilizing land cover/land use classification derived from Landsat and defining unique relationships for urban sub-classes(i.e.residential,commercial/industrial,open land),confusion between impervious and fallow agricultural lands has been overcome.Test results are presented for Ottawa-Gatineau,an urban area that encompasses many aspects typical of the North American urban landscape.Multiple QB scenes have been acquired for this urban centre,thereby allowing us to undertake an in-depth study of the error budgets associated with the fractional inference process.
