Fresh water is arguably the most vital resource for many aspects of a healthy and stable environment.Monitoring the extent of surface water enables resource managers to detect perturbations and long term trends in wat...Fresh water is arguably the most vital resource for many aspects of a healthy and stable environment.Monitoring the extent of surface water enables resource managers to detect perturbations and long term trends in water availability,and set consumption guidelines accordingly.Potential end-users of water-related observations are numerous and reflect society as a whole.They encompass scientists and managers at all levels of government,aboriginal groups,water/power utility managers,farmers,planners,engineers,hydrologists,medical researchers,climate scientists,recreation enthusiasts,public school to postgraduate students,many special interest groups and the general public.Water data and analyses generate information products that benefit water resources planning and management,engineering design,plant operations,navigation activities,health research,water quality assessments and ecosystem management.As well,they serve as inputs for flood and drought warnings and weather and climate prediction models.Radar data in general,and RADARSAT in particular,are very good for detecting open surface water and have been used operationally for flood monitoring in many countries.Significant radar data archives now exist to analyse seasonal,annual and decadal trends,in order to attain a better understanding of the freshwater cycle.Radar data are also useful for wetland classification and soil moisture estimation.With the increasing pressure on water resources,both from a quality as well as a quantity perspective,the need will continue to increase for reliable information.RADARSAT-2 has several innovations that will enhance the ability to provide useful information about water resources.This paper provides an overview of the use of radar in general,and RADARSAT-2 in particular,for the generation of information products useful to water resource managers.展开更多
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
The first pictures of the earth were taken from a balloon in the mid-19^(th) century and thus started‘earth observation’.Aerial missions in the 20^(th) century enabled the build-up of outstanding photographic librar...The first pictures of the earth were taken from a balloon in the mid-19^(th) century and thus started‘earth observation’.Aerial missions in the 20^(th) century enabled the build-up of outstanding photographic libraries and then with Landsat-1,the first civilian satellite launched in 1972,digital images of the earth became an operational reality.The main roles of earth observation have become scientific,economic and strategic,and the role of synthetic aperture radar(SAR)is significant in this overall framework.Radar image exploitation has matured and several operational programs regularly use SAR data for input and numerous applications are being further developed.The technological development of interferometry and polarimetry has helped further develop these radar based applications.This paper highlights this role through a description of actual applications and projects,and concludes with a discussion of some challenges for which SAR systems may provide significant assistance.展开更多
文摘Fresh water is arguably the most vital resource for many aspects of a healthy and stable environment.Monitoring the extent of surface water enables resource managers to detect perturbations and long term trends in water availability,and set consumption guidelines accordingly.Potential end-users of water-related observations are numerous and reflect society as a whole.They encompass scientists and managers at all levels of government,aboriginal groups,water/power utility managers,farmers,planners,engineers,hydrologists,medical researchers,climate scientists,recreation enthusiasts,public school to postgraduate students,many special interest groups and the general public.Water data and analyses generate information products that benefit water resources planning and management,engineering design,plant operations,navigation activities,health research,water quality assessments and ecosystem management.As well,they serve as inputs for flood and drought warnings and weather and climate prediction models.Radar data in general,and RADARSAT in particular,are very good for detecting open surface water and have been used operationally for flood monitoring in many countries.Significant radar data archives now exist to analyse seasonal,annual and decadal trends,in order to attain a better understanding of the freshwater cycle.Radar data are also useful for wetland classification and soil moisture estimation.With the increasing pressure on water resources,both from a quality as well as a quantity perspective,the need will continue to increase for reliable information.RADARSAT-2 has several innovations that will enhance the ability to provide useful information about water resources.This paper provides an overview of the use of radar in general,and RADARSAT-2 in particular,for the generation of information products useful to water resource managers.
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.
文摘The first pictures of the earth were taken from a balloon in the mid-19^(th) century and thus started‘earth observation’.Aerial missions in the 20^(th) century enabled the build-up of outstanding photographic libraries and then with Landsat-1,the first civilian satellite launched in 1972,digital images of the earth became an operational reality.The main roles of earth observation have become scientific,economic and strategic,and the role of synthetic aperture radar(SAR)is significant in this overall framework.Radar image exploitation has matured and several operational programs regularly use SAR data for input and numerous applications are being further developed.The technological development of interferometry and polarimetry has helped further develop these radar based applications.This paper highlights this role through a description of actual applications and projects,and concludes with a discussion of some challenges for which SAR systems may provide significant assistance.
