Alia Khan News

Seminar - From Field Sites to Satellites: Multi-Scale Remote Sensing and In Situ Observations of Cryospheric Albedo Reduction and Biogeochemical Feedbacks - Oct. 2

Jeff Zehnder — Mon, 28 Sep 2026 18:50:48 +0000

Seminar - From Field Sites to Satellites: Multi-Scale Remote Sensing and In Situ Observations of Cryospheric Albedo Reduction and Biogeochemical Feedbacks - Oct. 2 Jeff Zehnder Mon, 09/28/2026 - 12:50

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 �Ǹ�Թ�, 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.

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...

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Using aerospace technology to study glacier melt in Greenland

Jeff Zehnder — Fri, 10 Apr 2026 17:36:36 +0000

Using aerospace technology to study glacier melt in Greenland Jeff Zehnder Fri, 04/10/2026 - 11:36

Jeff Zehnder

Above: Khan collecting data on the Greenland ice sheet.
Header Image: A channel of flowing water on the ice sheet.

Alia Khan is integrating field-based biogeochemical analysis with NASA’s next generation satellite sensors to quantify how biological algae blooms, mineral dust, and wildfire smoke are darkening the Greenland Ice Sheet and accelerating its melt.

Khan, an associate professor in the Ann and H.J. Smead Department of Aerospace Engineering Sciences and the Environmental Engineering Program at the �Ǹ�Թ�, has been awarded a four-year, $857,000 NASA grant to develop tools to improve sea-level rise projections.

The work is focused on Greenland, home to massive amounts of frozen water in a large land-based glacier, also known as an ice sheet, that is nearly two miles thick in some places.

Increasing melt rate

“There are growing dark spots on the Greenland Ice Sheet,” Khan said. “While fresh snow is the most reflective surface on Earth, the ‘bare ice’ exposed during summer melt is naturally darker. When light-absorbing particles like algae and dust accumulate there, they further reduce reflectivity and cause the ice to melt even faster. Currently, this darkening isn't fully captured in most Earth system models, meaning we are likely underestimating future sea level rise.”

The enhanced darkening of the ice sheet is caused by the combined impact of soot, mineral dust, and seasonal ice algae blooms. These particles significantly increase heat absorption, creating a feedback loop that intensifies surface melting as the Arctic warms.

“Wildfires are becoming more frequent and intense, sending plumes of soot to settle on the ice,” Khan said. “At the same time, retreating glaciers leave behind fine dust that the wind blows back onto the surface. These particles, along with algae fueled by increased meltwater nutrients, are transforming the ice sheet from a reflective shield into a heat-absorber.”

New technology

To measure the impact, Khan is leveraging NASA’s PACE (Plankton, Aerosol, Cloud, ocean Ecosystem) satellite. Launched in 2024, PACE provides high-resolution hyperspectral imagery—capturing a vast spectrum of light from ultraviolet to infrared—to reveal details of the Earth’s surface that were previously invisible to orbiting sensors.

“PACE’s hyperspectral technology allows us to tease apart the unique spectral signatures of mineral dust and living algae,” Khan said. “By mapping these specific characteristics, we can determine exactly how each one contributes to surface melt, allowing us to improve our predictions for the future of the Greenland Ice Sheet.”

Khan will combine this data with planned in-person surveys of the Greenland ice sheet using drone flights and collection and analysis of surface samples of snow and ice.

Sailboats amidst icefloes off the coast of Greenland.

“The samples will be used to validate the satellite imagery and to measure specific quantities of dust, black carbon, and algae. This includes analyzing a suite of photosynthetic and photoprotective pigments, as well as conducting DNA analysis,” she said.

Like nowhere else

Spending time on the ice sheets is a unique and rare opportunity. Accessible only via helicopter, they are places few humans have seen up close.

“There’s a pretty significant wind chill and survival gear is necessary, whether or not we plan to spend the night, but it’s such a privilege to work in a place almost completely untouched by humans,” Khan said.

The collected data and images will be used in the creation of complex new algorithms to more accurately map the dark zones throughout the melt season.

“It takes a lot of computing power, but there’s so much exciting new technology we can apply here to build models we haven’t had before,” Khan said.

As Greenland's ice loss remains a primary driver of global sea-level rise, by refining our understanding of Greenland’s melt rates, Khan’s work fills a critical gap in the climate models used by scientists and policymakers to improve future projections.

Additional investigators on the grant include Peng Xian at the U.S. Naval Research Laboratory and Heidi Dierssen at the University of Connecticut.

Alia Khan is integrating field-based biogeochemical analysis with NASA’s next generation satellite sensors to...

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Welcoming Associate Professor Alia Khan to Smead Aerospace

Jeff Zehnder — Fri, 05 Sep 2025 22:17:11 +0000

Welcoming Associate Professor Alia Khan to Smead Aerospace Jeff Zehnder Fri, 09/05/2025 - 16:17

Fall 2025 is bringing a new faculty member to the Ann and H.J. Smead Department of Aerospace Engineering Sciences.

Alia Khan is joining the �Ǹ�Թ� as an associate professor in Smead Aerospace and the Environmental Engineering Program.

Khan comes from Western Washington University, where she was an associate professor in their environmental sciences department, but she is no stranger to CU �Ǹ�Թ�. She completed graduate school here, earning her master’s in environmental studies in 2012 and PhD in civil and environmental engineering in 2016. During that time, her research was conducted at the Institute of Arctic and Alpine Research. She then went on to complete a postdoctoral fellowship at the National Snow and Ice Data Center on campus.

A North Carolina native, Khan has had a life-long affinity for snow, which is central to her research. She combines environmental chemistry and optical remote sensing from uncrewed aerial vehicles and orbiting satellites to document snow and ice melt in mountainous and polar regions. Khan also has strong expertise in autonomous system development for environmental monitoring, aquatic biogeochemistry, aerosols, the cryosphere, and glacial and snow hydrology.

She has led research grants funded by NASA and the National Science Foundation, which recognized her with a $1.3 million CAREER Award in 2021 to investigate snow darkening in Antarctica. She is beginning a new NASA-funded award to study Greenland’s dark ice zones from space. She is a recipient of the US Fulbright Scholar Award and an Antarctic Service Medal.

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