 in astronomy and physics in 1971 from the University of Michigan and earned his Ph.D in Geophysics from the University of Washington in 1978 and did post doctoral work in Switzerland prior to working at NASA.His work revolves around the dynamics of glaciers and ice sheets using remote sensing technology.He has developed applications used to measure ice velocity and elevation using radar imagery which monitors the melting of ice sheets and detects changes in the volume of ice-sheets using radar altimetry.