presented by Dr. Shadi Oveis Gheran
Graduated fromStanford Universityand a researcher atNASA
The talk is divided in two parts:
Cryosphere Application of Radar Remote Sensing:
Snow accumulation in remote regions such as Greenland and Antarctica is a key factor for estimating Earth’s ice mass balance. In situ data are sparse; hence it is useful to derive snow accumulation from remote sensing observations. Here we introduce an ice scattering model that relates InSAR correlation and radar brightness to both ice grain size and hoar layer spacing in the dry snow zone of Greenland.We use this model and ERS satellite radar observations to derive several parameters related to snow accumulation rates in a small area in the dry snow zone. These parameters show agreement with four in situ core accumulation rate measurements in this area, while models using only radar brightness data do not match the observed variation in accumulation rates.
Carbon Cycle Application of Radar Remote Sensing:
Estimation of forest height from combined interferometric and polarimetric synthetic aperture radar (Pol-InSAR) measurements has been the focus of radar remote sensing studies in the past decade. In this study, we present a physically based model to simulate the Pol-InSAR measurements. The model is based on electromagnetic wave theory and the distorted born approximation and the forest canopy is represented by a layer of discrete randomly distributed dielectric scatterers (e.g. leaves, branches, and stems) with vertical and horizontal heterogeneity over a rough soil surface. The interferometric cross-correlation is formulated from three dominant scattering mechanisms of volume, surface-volume interaction, and surface scattering from the forest floor.
Shadi Oveisgharan was born in Isfahan, Iran. She received her BSc degree from Sharif University of Technology, Tehran, in 1999 and an MS degree from the University of Michigan, Ann Arbor in 2002, both in electrical engineering. She received her PhD in electrical engineering from Stanford University, where she worked on modeling InSAR observations from the dry snow zone of Greenland.
She awarded NASA Post-Doctoral Program (NPP) in 2007 and worked as a NASA Post-Doctoral Fellow at the Jet Propulsion Laboratory from 2008 to 2010. Her Post-doctoral research at JPL included scattering modeling of the Pol-InSAR observations from vegetated areas. She joined NASA-JPL as a scientist in 2010 and was involved in many different projects and missions including being a research scientist staff for NISAR and SMAP missions. Her current research interests include electromagnetic scattering theory and radar remote sensing.