CIRFA welcomes you to seminar on:
Date: Thursday 26 May, 14:30-15:30 (NB! changed time!)
Venue: CIRFA, Forskningsparken 3, 3rd floor, Tromsø
Introductions by Stine Skrunes and Xu Xu
The effect of imaging geometry on multipolarization SAR for oil spill observation
Stine Skrunes (Postdoc, UiT CIRFA)
Synthetic Aperture Radar (SAR) is a well-established tool for remote sensing of marine oil spills and is currently used operationally for oil spill detection. Much research focuses on slick characterization, i.e., discrimination between oil spills and look-alikes, and extraction of oil spill information. This topic is frequently addressed using SAR polarimetry and multipolarization features. However, SAR backscatter from surface slicks depends on a number of factors related to slick characteristics, environmental conditions and sensor properties. Knowledge about how these factors affect the multipolarization parameters and slick detectability is important for the development of reliable detection and characterization methods with a large validity range. The objective of this work is to investigate how oil spill observation using polarimetric SAR is affected by imaging geometry, specifically the incidence angle and the look direction relative to the wind. The effect of the geometry on feature values as well as on slick detectability is evaluated and compared. The study is performed on data collected by the National Aeronautics and Space Administration (NASA) Uninhabited Aerial Vehicle Synthetic Aperture Radar (UAVSAR), which is an airborne L-band SAR instrument. The data was collected over experimental oil spills in the North Sea in June 2015.
Numerical Simulation of Microwave Scattering From Sea Ice Based on Finite Element Method
Xu Xu (PhD fellow, UiT)
This presentation introduces a scattering model for sea ice based on Finite Element Method (FEM). Electromagnetic (EM) Modeling studies can be undertaken to simulate the expected backscattering from hypothetical sea ice medium. Through models, the measured SAR signature of sea ice can be related to its physical properties. And we can study which parameters are most sensitive to SAR signature.
FEM is a numerical technique for finding approximate solutions to Partial Differential Equations (PDE) by dividing the whole computional domain into subdomains of simple geometry called finite elements. Through FEM, the PDE problems can be translated into a set of linear algebraic equation. FEM has a flexible meshing procedure, which makes it well suited to heterogeneous structures and inhomogeneous volume scattering. The basics of FEM and its application on solving surface scattering problem will be presented.