TUTORIAL

Sha

Informations

• Publié par: Nisig
• Nombre de lectures: 35
• Langue: English

Extrait

HUT TUTORIALPhotogrammetry & Remote Sensing: Deformation Measurements Dr.techn.habil. Aleksey I.Sharov:SATELLITE RHEOLOGY OF ICE FIELDS “In order to prepare for specific conditions in an environment, one must determine the modes of motion in that environment” (Levis, Giuffrida 1989) 25.11.04 1. PREFACE / INTRODUCTION / MOTIVATION Historical background, basic definitions Study objects, rheological unknowns, data / knowledge gaps Need for rheological knowledge and models National and international programmes, relevant research projects Relevant remote sensing missions: post-operational, operational and ongoing systems 2. FUNDAMENTALS OF ICE RHEOLOGY Basic parameters of ice mechanics Surface elevation, ice thickness, freeboard Coordinate / reference systems Modes of ice flow, flow field, ice velocity and ice flux The condition of incompressibility Sea ice momentum equation Stresses and strain rates, Gordon law, Glenn law  Dislocationsin the ice cover (crevasses, cracks, bulges, ridges, rafting, fracturing etc.) Physical constants relevant to ice flow and deformation, their variability 3. SPACEBORNE SAR INTERFEROMETRY (INSAR) (IN)SAR fundamentals and basic concepts (SAR, SNR, et al.) INSAR geometry, technical parameters (IN)SAR equations INSAR operating modes and configurations Interferometric signal characteristics  INSARdata processing – workflow  INSARprocessing techniques •complex correlation, image co-registration, re-sampling •phase processing / unwrapping techniques •phase gradient estimation (GINSAR) •geocoding operations. Advanced software tools and computer requirements 4. DIFFERENTIAL INSAR Basic differential equation Underlying concept and methodological variants •2-pass DINSAR •3-pass DINSAR •4-pass DINSAR •Multi-pass DINSAR •PS technique

•0-baseline INSAR Methodological alternatives •Differential GINSAR •Transferential INSAR •ERS - ENVISAT cross-interferometry 5. RHEOLOGICAL APPLICATIONS OF (D)INSAR Review of (D)INSAR products Conventional products -Interferogram -Amplitude image -Coherence image -Fringe image Value-added products -Topogram -Slope map -DSM / DEM -Orthoimages -Fluxogram (differential interferogram) -Strain rate image product -Velogram Glacier change detection and monitoring Interferometric mapping of ice flow and deformation Interpretation of ice coasts and ice divides in SAR interferograms INSAR representation of fast sea ice attached to glacier fronts Assessing specific geophysical effects controlling fast ice deformation Measurement of frontal glacier velocities in single interferograms Studying available analogies in the area of interferometric control General overview of other applications, both direct and indirect 26.11.04 6. VALIDATION OF INSAR DETERMINATIONS  Revisedstrategy of INSAR validations Terrestrial techniques & reference points Accuracy analysis & (D)INSAR error sources  Assessingthe information contents of interferometric maps Algorithmic singularities •Relative character of interferometric measurements •Foreshortening, layover and shadowing •Problematic geocoding •Spatial and temporal decorrelation •Phase noise and speckle effect •Methodical sensitivity and dynamic diapason •Other limitations to (D)INSAR 7. SATELLITE ALTIMETRY OF ICE FIELDS  Basicparameters of current and future satellite altimetry systems

•ERS - RA •ENVISAT - RA2 •ICESat – GLAS •CryoSat – SIRAL Data products •Surface elevation •Surface slope •Surface roughness •Surface reflectivity / backscattering •Waveforms Interpretation of dual-frequency altimetry data Topographic mapping and hypsometric change detection 8. JOINT PROCESSING OF INSAR AND ALTIMETRY DATA Co-registration of spaceborne INSAR and altimetry data Generation of composite products Geocoding / upgrading of INSAR products and adjusting INSAR blocks Enhanced morphometric determinations  Jointinterpretation of outflows in INSAR and altimetry data  Jointinterpretation of ice divides in interferential and altimetry transects  RSGsoftware for INSARIN data processing: architecture and functionalities 9. SIMPLE RHEOLOGICAL MODELS FROM SATELLITE INTERFEROMETRY AND ALTIMETRY 1-D vs 3-D rheological models  Uniaxialelastic deformation vs viscous and plastic deformations  Assessmentof basic terms in sea-ice momentum equation  Unbalancedhorizontal (driving) stress at the glacier face Energy conservation principle Main rheological inferences from and principal limitations to SRMs 10. SATELLITE RHEOLOGY: PROMISES, REALITIES AND FUTURE DEVELOPMENTS Perspective systems •E-SAR airborne across- and along-track interferometry •ScanSAR, burst and polarimetric interferometry •RADARSAT 2, TerraSAR, PALSAR, La Crosse snap shots •Interferential altimetry SARIN •Interferometric cart-wheel •Terrestrial interferometry New applications •“Multi” concept (frequency, polarisation, baseline, image mode, coverage) •New repetition cycles and spectral bands (L, P) •ERS-ENVISAT cross-interferometry •INSARIN data fusion Concluding remarks