She has more than two decades of experience in atmospheric remote sensing using infrared Fourier transform spectroscopy and development of instrumentation for ground-based, balloon-borne and satellite-based measurements. Prior to this, she was trained and worked for four years in the area of high-resolution microwave and millimeter-wave spectroscopy and laboratory instrument development. Prof. Walker leads the satellite validation activities within the PEARL-CANDAC team. Since 2004, she has co-led annual springtime Arctic campaigns at PEARL in Eureka, Nunavut to support validation of the ACE and OSIRIS satellite instruments and is active in using the PEARL measurements for assessing satellite data.