Use of Radarsat Data in the Canadian Ice Service

Ramsay, B.; Manore, M.; Weir, Laurie; Wilson, K.; Bradley, David M.

doi:10.1080/07038992.1998.10874689

Cited by 24 publications

(20 citation statements)

References 1 publication

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“…Consequently, previous studies lack the accuracy, scale and consistency to monitor the polynya through different seasons. The RADARSAT-1 satellite (C-band, HH polarization) ScanSAR Wide (SCW) data offers 100-m resolution (50-m pixel spacing) within a 450-500 km swath width (Ramsay et al, 1998), thus making it suitable for polynyascale observations. The polar orbit of the satellite provides a daily revisit period over Canadian regions north of 60°N, allowing for frequent temporal sampling capable of capturing diurnal ice motion.…”

mentioning

confidence: 99%

Validation and production of RADARSAT‐1 derived ice‐motion maps in the North Water (NOW) polynya, January ‐ December 1998

Wilson¹,

Barber

King

2001

Atmosphere-Ocean

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Monitoring ice motion may provide insight into the atmospheric and oceanic forces acting on ice motion and thus the mechanisms that contribute to polynya dynamics. A study of ice kinematics in the North Water (NOW) region was performed using time sequential and spatially overlapping RADARSAT-1 ScanSAR Wide images (January to December 1998) processed by the Canadian Ice Service (CIS) Ice Tracking Algorithm (Tracker). The objectives of this research were to: 1) validate the NOW region ice motions derived using Tracker; 2) create monthly image-maps that present ice speeds and directions over the NOW region for an entire year (January to December 1998); 3) compare these results to previous ice motion studies done in the NOW region; and 4) develop initial insights into relations between derived ice motion and latent and sensible heat mechanisms in the NOW Polynya. Tracker ice motions were validated using in situ ice beacons deployed between April and November 1998. Tracker magnitude and direction coefficients of determination (R 2 ) were 0.93 and 0.79 respectively, with standard errors of estimate of 3.6 km in magnitude and 38.8° in direction. The monthly ice motion maps describe the annual evolution of the polynya quite accurately and compare well to other studies. High levels of ice export are found which supports the theory that winds or ocean currents continually remove ice from the polynya as it forms. A northward import of ice into the polynya along the Greenland coast shows the recycling of ice into the polynya. Evidence of oceanic (sensible) heat contributing to the open water of the polynya was not evident using the Tracker ice motion methods. RÉSUMÉ [Traduit par la rédaction] La surveillance du mouvement des glaces peut donner un aperçu des forces atmosphériques et océaniques qui déterminent le mouvement des glaces et donc des mécanismes qui participent à la dynamique de la polynie. Une étude de la dynamique des glaces a été réalisée dans la région de la polynie des eaux du Nord à l'aide d'une séquence temporelle d'images qui se chevauchent dans l'espace. Ces images, de type ScanSAR Large, ont été produites de janvier à décembre 1998 par RADARSAT-1 et traitées par l'algorithme de poursuite des glaces (Tracker) du Centre canadien des glaces (CCG). L'étude avait pour objectifs : 1) de valider le mouvement des glaces dérivé par le Tracker dans la région de la polynie des eaux du Nord; 2) de créer des cartes-images mensuelles des vitesses et des directions des glaces dans cette région pour toute l'année (de janvier à décembre 1998); 3) de comparer ces résultats aux études précédentes sur le mouvement des glaces faites dans la région; et 4) de donner une première idée des relations qui existent entre le mouvement dérivé des glaces et les mécanismes de chaleur latente et sensible dans la polynie des eaux du Nord. Les mouvements des glaces donnés par le Tracker ont été validés par des balises à glace déployées sur place entre avril et novembre 1998. Les coefficients de détermination (R 2 ) de la grandeur et de la...

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confidence: 99%

Validation and production of RADARSAT‐1 derived ice‐motion maps in the North Water (NOW) polynya, January ‐ December 1998

Wilson¹,

Barber

King

2001

Atmosphere-Ocean

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“…The size of the SAR image being processed in Figure 4 is 5334 pixels 6 4751 pixels (2 6 2 block average (Bertoia and Ramsay, 1998) of the original ScanSAR wide image at resolution 100 m and pixel spacing 50 m) and contains 88 polygons. Some general information related to the current image such as image directory, image size, coordinate of the current mouse cursor location, and the total polygon number in the image is displayed in the title and status bars.…”

Section: Navigating the Guimentioning

confidence: 99%

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2010

Canadian Journal of Remote Sensing

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“…The imagery is often downloaded directly to the ship, where it is interpreted by a skilled observer and a path is determined empirically [Ramsay et al, 1998]. To be able to compute such paths automatically, it is desirable that the ice thickness, or at least geophysically relevant information about the nature of the ice cover, be derived from the satellite imagery.…”

Section: Introductionmentioning

confidence: 99%

Informational equivalence between synthetic aperture radar imagery and the thickness of Arctic pack ice

Kerman¹,

Wadhams²,

Davis³

et al. 1999

J. Geophys. Res.

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Abstract. The negative exponential form of the conditional probability of both differences in synthetic aperture radar (SAR) intensity and differences in thickness between neighbors is used as the basis of a representation of structural information in terms of textural information for sea ice. The analysis is based on a unique data set involving airborne SAR flights over the track of a submarine that simultaneously profiled ice thickness by means of an upwardly directed sonar. It is shown that both sets of data, namely, imagery and thickness, possess an identical conditional probability relationship. This probability is composed of both a fractal property for spatial separations and a simple negative exponential distribution for intensity or thickness differences for fixed separations. These properties allow for the derivation of two forms of information: textural and structural. An intercomparison of the structural information in terms of the textural information is offered for the same ice field as imaged by a SAR and measured from a submarine for its thickness. It is shown that the information curves for both the imagery and thickness have a similar geometrical form. It is demonstrated that three subranges within the information curves correspond to three visibly identifiable ice types and three thickness ranges associated previously with these ice types. It is suggested that an understanding of the transformation between the two sets of information states might provide estimated statistics of Arctic ice thickness from SAR imagery.

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Use of Radarsat Data in the Canadian Ice Service

Cited by 24 publications

References 1 publication

Validation and production of RADARSAT‐1 derived ice‐motion maps in the North Water (NOW) polynya, January ‐ December 1998

Validation and production of RADARSAT‐1 derived ice‐motion maps in the North Water (NOW) polynya, January ‐ December 1998

Full Issue in PDF / Numéro complet enform PDF

Informational equivalence between synthetic aperture radar imagery and the thickness of Arctic pack ice

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