Enhancing our understanding of cloud and aerosol optical properties is crucial for reducing uncer-
tainties related to their radiation effects. The Polarization Lab specializes in developing advanced
instrumentation to accurately quantify the impact of clouds and aerosols on radiation transfer in the
atmosphere. Sunlight is inherently unpolarized, but when it interacts with the atmosphere, scattering
processes induce partial polarization in different wavebands of the electromagnetic spectrum. Mea-
suring atmospheric scattering through specular, angular and polarimetric sampling is highly valuable, and
the combination of these approaches yields even greater insights.
For aerosols, polarimetry enables a more nuanced understanding of whether they predominantly
scatter or absorb light. This distinction is vital for assessing their impact on atmospheric radiation. In
the case of clouds, polarization measurements help determine their thermodynamic phase—whether
they consist of ice or water—and provide insights into ice crystal formations. This information is
critical for improving climate models and understanding weather patterns. Both aerosols and clouds
affect the overall radiation budget of the Earth, i.e. how much heat is radiated back into space versus
trapped within our atmosphere.
The Polarization Lab has collaborated with NASA and the Jet Propulsion Laboratory on the
development of polarimeters such as the Ground-based and Airborne Multiangle Spectropolarimetric
Imager (GroundMSPI/AirMSPI) and the Multi-Angle Imager for Aerosols (MAIA) to enable cloud
and aerosol research. The Infrared Channeled Spectropolarimeter (IRCSP) and the Ultraviolet Linear
Stokes Imaging Polarimeter (ULTRASIP) are currently in development for cloud studies and aerosol
studies, respectively