Cooperative Institute for Research in Environmental Sciences

Cryospheric and Polar Processes Seminar: Dr. Albert Chen

Cryospheric and Polar Processes Seminar: Dr. Albert Chen

InSAR Remote Sensing: Principles and Applications to Greenland and Alaska

Dr. Albert Chen, Department of Gephysics, Standford University

Abstract

Interferometric synthetic aperture radar (InSAR) is a technique for forming images of the Earth using data acquired by a spaceborne or airborne radar instrument. The complex phase of InSAR images can be used to measure Earth surface topography and deformation, while the secondorder phase statistics (coherence) can be related to temporal surface change and subsurface structure. After a brief overview of InSAR principles, error sources, and uncertainties, we present two applications of InSAR to cryosphere geophysics. First, we examine the use of InSAR coherence for studying snow accumulation rate in the dry-snow zone of the Greenland Ice Sheet.

We show a method for correcting decorrelation effects due to ionospheric inhomogeneity. We pose the estimation of accumulation rate from InSAR data as a nonlinear inverse problem, and compare our results with in-situ observations. Second, we use InSAR phase to study active layer thickness in regions of permafrost in Northern Alaska. We relate seasonal thaw subsidence measured by InSAR to active layer thickness, and use InSAR time series analysis to mitigate the effects of atmospheric noise.

Bio

Albert C. Chen was born in Columbus, Ohio and grew up in New York and Michigan. He received the B.S.E. degree from the University of Michigan, Ann Arbor, in 2006. He also received the M.S. and Ph.D. degrees in electrical engineering from Stanford University in 2008 and 2014, respectively. Currently, he is a postdoctoral scholar in the Department of Geophysics at Stanford University. Albert has also been an engineering intern with The Boeing Company and Visteon Corporation. His research interests range from interferometric synthetic aperture radar (InSAR), remote sensing, radar instrument design, and signal processing to cryosphere and near-surface geophysics. He is a member of AGU and IEEE, and has also served as teaching assistant for undergraduate and graduate courses in signal and image processing.