Seminar - From Field Sites to Satellites: Multi-Scale Remote Sensing and In Situ Observations of Cryospheric Albedo Reduction and Biogeochemical Feedbacks - Oct. 2
Alia Khan
Associate Professor, Smead Aerospace
Friday, Oct. 2 | 10:40 A.M. | AERO 111
Abstract: The global cryosphere is undergoing rapid transformation. A missing component of snow and ice melt projections is biologically driven albedo reduction from algal blooms growing on snow and ice surfaces. Other light-absorbing particles (LAPs), including wildfire-derived black carbon and mineral dust, not only directly drive cryospheric darkening, but also indirectly serve as nutrient sources for snow and ice algae. Resolving these fine-scale, dynamic bio-optical and aerosol feedbacks across regional and global scales is essential to constraining major sources of uncertainty in Earth system modeling, water resource management, and sea-level rise projections. This seminar presents an integrative research framework that bridges aerospace remote sensing, analytical wet-lab biogeochemistry, and spectral geophysics to address these multi-scale feedbacks.
Exploiting the distinct absorption features of algal pigments and dust mineralogy, my research group leverages multi-platform observations by combining multi-sensor UAV payloads, low-latency commercial SmallSat data (SkySat), and spaceborne hyperspectral sensors (NASA PACE) to unmix discrete spectral signatures (e.g., penguin guano from snow algae and dust) and map surface darkening at resolutions ranging from sub-centimeter scales using UAVs to 0.5 meters via commercial satellites. Ground-based and laboratory analyses (e.g., LC-Q/TOF mass spectrometry, flow cytometry, and SP2-XR/D single-particle aerosol soot characterization) are used to validate aerial observations, develop novel algorithms for remote concentration retrieval, and evaluate Snow Ice Aerosol Radiation (SNICARv3) model parameterizations against in-situ hyperspectral albedo measurements.
To overcome operational hazards in extreme environments, we are also developing autonomous field robotics, including a custom NSF-funded, UAV-mounted robotic sampler—designed and built with CU engineering students—for remote physical sample retrieval across hard-to-access polar and glaciated terrain. Finally, this presentation highlights scholarly contributions since Fall 2022, including external research funding across NASA and NSF supporting field campaigns in Antarctica, Greenland, Alaska, and the North Cascades.
Bio: Dr. Alia Khan is an Associate Professor in Aerospace Engineering Sciences at CU °Ç¸ç³Ô¹Ï, where she leads the Cryosphere Remote Sensing and Biogeochemistry Group. She is an alumna of the CU Environmental Engineering program and INSTAAR. After completing her PhD in 2016, she then worked as a Postdoc at the National Snow and Ice Data Center with a primary focus on water and snow chemistry in High Mountain Asia as part of a USAID funded project. Dr. Khan was an Assistant and Associate Professor at Western Washington University in Bellingham from 2019 - 2025 before returning to CU.