Water resource applications with RADARSAT-2 – a preview

Abstract

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.

Compact polarimetry assessment for rice and wetland mapping

“…Adding the beta parameter to the Cloude-Pottier decomposition could improve the classification to a similar level of the Freeman-Durden as was found for rice classification (Li, Brisco, and Yun 2012) Note, however, that both the C-L CP and fully polarimetric data produced operationally suitable wetland classification accuracies. It is not surprising that the full polarimetric data outperformed other data sets as it did for rice due to the increased information content (Brisco et al 2008Touzi 2007). …”

“…Synthetic aperture radar (SAR) has been recognized as an important source of data for water resource applications (Brisco et al 2008). For surface water and flooding applications, the lack of backscatter from the specular water surface allows for easy delineation of open water, while the flooded vegetation in wetlands results in an enhanced backscatter due to double-bounce scattering (Hess, Melack, and Simonett 1990;Kasischke and Bourgeau-Chavez 1997;Pope et al 1997;Brisco et al 2009Brisco et al , 2011.…”

A Collection of SAR Methodologies for Monitoring Wetlands

“…This allows the user to decompose the SAR backscatter being returned from the objects being sensed into four common scattering types: (1) specular scattering (no return to the SAR), which occurs from smoother surfaces such as calm water or bare soil; (2) rough scattering, which results when there is a single bounce return to the SAR from surfaces such as small shrubs or rough water; (3) volume scattering, which is when the signal is backscattered in multiple directions from features such as vegetation canopies; and (4) double-bounce or dihedral scattering, which results when two smooth surfaces create a right angle that deflects the incoming radar signal off both surfaces such that most of the energy is returned to the sensor. This latter scattering case typically occurs when vertical emergent vegetation is surrounded by a visible, smooth water surface [32,[47][48][49][50][51]. Flooded vegetation can also have a combination of double-bounce and volume backscattering [50,51].…”

“…Synthetic Aperture Radar (SAR) technology can be effective for monitoring changes in surface water [32,33] and wetlands both seasonally and annually [34−37]. SAR has many characteristics that make it ideal for mapping and monitoring water and wetlands over time.…”

Operational Surface Water Detection and Monitoring Using Radarsat 2

“…Water monitoring using Synthetic Aperture Radar (SAR) has been the object of study for many researchers [3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19]. Due to its all-weather capabilities, and its image acquisition capacity during day or night or in cloudy conditions, SAR imagery offers better alternatives for water mapping than optical imagery [5].…”