Systems for data processing, anaylsis and representation

Allam, Mosaad; Plunkett, Gordon

Bibliographic data

Monograph

Persistent identifier:: 1067490280

Title:: Systems for data processing, anaylsis and representation

Sub title:: ISPRS Commission II Symposium : June 6 - 10, Ottawa, Canada

Scope:: 1 Online-Ressource (XX, 530 Seiten)

Year of publication:: 1994

Place of publication:: Ottawa

Publisher of the original:: The Surveys, Mapping and Remote Sensing, Natural Resources Canada

Identifier (digital):: 1067490280

Illustration:: Illustrationen

Signature of the source:: ZS 312(30,2)

Language:: English

Additional Notes:: Erscheinungsdatum des Originals ist aus dem Copyrightjahr ermittelt.

Usage licence:: Attribution 4.0 International (CC BY 4.0)

Editor:: Allam, Mosaad; Plunkett, Gordon

Corporations:: Symposium Systems for Data Processing, Analysis and Representation, 1994, Ottawa; International Society for Photogrammetry and Remote Sensing; International Society for Photogrammetry and Remote Sensing, Commission Instrumentation for Data Reduction and Analysis; Kanada, Surveys, Mapping and Remote Sensing Sector

Adapter:: Symposium Systems for Data Processing, Analysis and Representation, 1994, Ottawa; International Society for Photogrammetry and Remote Sensing; International Society for Photogrammetry and Remote Sensing, Commission Instrumentation for Data Reduction and Analysis; Kanada, Surveys, Mapping and Remote Sensing Sector

Founder of work:: Symposium Systems for Data Processing, Analysis and Representation, 1994, Ottawa; International Society for Photogrammetry and Remote Sensing; International Society for Photogrammetry and Remote Sensing, Commission Instrumentation for Data Reduction and Analysis; Kanada, Surveys, Mapping and Remote Sensing Sector

Other corporate:: Symposium Systems for Data Processing, Analysis and Representation, 1994, Ottawa; International Society for Photogrammetry and Remote Sensing; International Society for Photogrammetry and Remote Sensing, Commission Instrumentation for Data Reduction and Analysis; Kanada, Surveys, Mapping and Remote Sensing Sector

Publisher of the digital copy:: Technische Informationsbibliothek Hannover

Place of publication of the digital copy:: Hannover

Year of publication of the original:: 2019

Document type:: Monograph

Collection:: Earth sciences

Chapter

Title:: [Wednesday, June 8, 1994]

Document type:: Monograph

Structure type:: Chapter

Chapter

Title:: [Poster Session 2-A]

Document type:: Monograph

Structure type:: Chapter

Chapter

Title:: OBSERVATIONS OF A COASTAL CURRENT USING ERS-1 SAR PIERRE LAROUCHE

Document type:: Monograph

Structure type:: Chapter

ale au SPG procédés nformation s le cadre cadastral l'échelle fectué au moderniser ographies iques de 293; iii) oduire, 3 'S pouvant , dont’ la s 15 à 20 5 auteurs nent d'un |! méthode le facon à ivail tout facilite out début essive et pays ou 'essite de Vi OBSERVATIONS OF A COASTAL CURRENT USING ERS-1 SAR PIERRE LAROUCHE Institut Maurice-Lamontagne, Ministére des Péches et des Océans B.P. 1000, Mont-Joli, Québec Canada G5H 3Z4 Commission II, Group 4 KEY WORDS: SAR, ERS-1, Currents, Circulation, Oceanography EXTENDED ABSTRACT Coastal currents are important dynamical phenomena's in the marine ecosystem. Currents such as the Gulf Stream and the Kurushio are major forces transporting heat from the equatorial regions to the poles regulating the heat budget of the Earth. Regionally, currents also transport pollutants and fish larvae between the different coastal ecosystems. It thus appear important to evaluate the long-term variability of these currents in the context of global change. Unfortunately, coastal currents often exhibit a strong spatial variability making it difficult to monitor their behavior using in-situ measurements. Only remote sensing can provide the large scale vision necessary to observe these variations. Thermal infrared remote sensing has often been the primary tool used to observe currents such as the Gulf Stream. The presence of clouds is the most often encountered problem with the use of such sensors and alternate means of observing these currents would be welcomed. For large-scale currents, radar altimetry is one of the available tools. It is however hardly usable for smaller scale coastal currents of a few kilometers width. Theoretical work showed that current shears should be detected by space borne synthetic aperture radars (SAR). To be detected, such shears should be of the order of 10-4 s-1. The Gaspé current located in the St. Lawrence Gulf (Canada) is a coastal current that meets this criteria. The goal of this project was thus to verify the possibility for a space borne instrument to detect the location of coastal currents by comparing active microwave C-band SAR data with concurrent in-situ measurements of current shears. Two ERS-1 MLD SAR images (September 25 1991 and May 19 1992) were used for the first phase ofthe project. In-situ measurements consisted of a series of transects perpendicular to the mean current direction made during the two satellite overpass using an acoustic Doppler current profiler (ADCP). Salinity and temperature profiles were also gathered during the transects to determine the density structure of the current. Image processing first consisted of locating the transects location and extracting sub-images corresponding to these areas. An adaptive Frost filter was then applied on these sub-images to remove speckle while preserving the high frequency features present. Grey level values were then extracted from the images along a line corresponding to the ship track and smoothed using a running mean of size 10. The analysis of the data from the three transects indicates that the ERS-1 SAR detected the location of the Gaspé current boundary when environmental conditions were favorable (winds between 1 and 5 m s- 1) thus opening the possibility of using this tool to monitor coastal currents. It was thus shown that shears of 1 x 10-4 s-1 were indeed detectable as predicted by theory. The observations in this experiment were however made only with a current flowing roughly in the SAR range direction. Further observations should thus be made with a broader set of currents (including azimuth traveling Cents) to further evaluate the capacity of a space borne SAR to detect this type of dynamical atures. OBSERVATIONS D'UN COURANT COTIER AU MOYEN DU RADAR A SYNTHÈSE D'OUVERTURE DU ERS-1 323

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