Electromagnetic reflectance and emissivity are complementary radiative properties describing how materials interact with incident and thermally emitted electromagnetic radiation as a function of wavelength, polarization, and angle. Reflectance quantifies the fraction of incident radiant flux reflected by a surface, decomposable into specular and diffuse components and governed by Fresnel relations and surface roughness. Emissivity is the ratio of a surface’s spectral radiance to that of an ideal blackbody at the same temperature, constrained by Kirchhoff’s law such that, under thermal equilibrium, spectral emissivity equals spectral absorptance. Together, these properties are fundamental for radiative transfer modeling, remote sensing retrievals, thermal infrared imaging, and energy balance analysis.
A new study by Hashem Akbari, a professor in the Department of Building, Civil and Environmental Engineering, offers a simplified way of calculating the degree to which surface reflectivity, known as albedo, can offset carbon ...
Environment
Apr 14, 2026
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From space, Earth's populated areas glow on the otherwise "black marble" of the planet at night. For decades, scientists assumed this glow was steadily increasing as the world developed. However, a new study published in ...
Environment
Apr 8, 2026
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As human-caused climate change continues to raise temperatures across the globe, understanding how birds regulate their temperature is vital for their conservation. But how much heat birds emit—an invisible spectrum of radiation ...
Plants & Animals
Mar 22, 2026
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"Sunlight" beams off a partly cloudy Atlantic Ocean just after sunrise as the International Space Station orbited 263 miles above on March 5, 2025. This is an example of sunglint, an optical phenomenon that occurs when sunlight ...
Planetary Sciences
Mar 2, 2026
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The Earth became darker from 2001 to 2024, meaning it reflects less sunlight, a research team reports in the journal Proceedings of the National Academy of Sciences.
Earth Sciences
Sep 30, 2025
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Land surface temperature (LST) is a critical parameter for understanding Earth's energy balance and monitoring climate change. However, due to the limited spatial resolution of current satellite observations, LST measurements ...
Environment
Jul 23, 2025
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In a groundbreaking, first-of-its-kind milestone for coral restoration, scientists from the University of Miami Rosenstiel School of Marine, Atmospheric, and Earth Science, Tela Marine and The Florida Aquarium have outplanted ...
Ecology
Jul 15, 2025
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99
New results published in the journal Physical Review Letters detail how a specially designed metamaterial was able to tip the normally equal balance between thermal absorption and emission, enabling the material to better ...
The chameleon, a lizard known for its color-changing skin, is the inspiration behind a new electromagnetic material that could someday make vehicles and aircraft "invisible" to radar.
Condensed Matter
Jan 22, 2025
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104
Combining metallic glass with the Berreman mode of epsilon-near-zero (ENZ) thin films achieves a dual-function system for infrared camouflage and thermal management within an identical wavelength region of the atmospheric ...
Optics & Photonics
Dec 27, 2024
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