Accurately Quantifying Clear-Sky Radiative Cooling Potentials: A Temperature Correction to the Transmittance-Based Approximation
Department of Materials Science and Engineering, University of California, Los Angeles, CA 90024, USA
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Authors to whom correspondence should be addressed.
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These authors contributed equally to the work.
Academic Editors: Giulia Ulpiani, Chi-Yan Tso and Yu-Bin Chen
Atmosphere 2021, 12(9), 1195; https://doi.org/10.3390/atmos12091195
Received: 17 August 2021
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Revised: 9 September 2021
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Accepted: 13 September 2021
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Published: 15 September 2021
(This article belongs to the Special Issue On the Variability of Atmospheric Transparency: Key Players, Geographic Specificities and Implications for Daytime Radiative Cooling)
Theoretical calculations of the cooling potential of radiative cooling materials are crucial for determining their cooling capability under different meteorological conditions and evaluating their performance. To facilitate these calculations, accurate models of long-wave infrared downwelling atmospheric irradiance are needed. However, the transmittance-based cosine approximation, which is widely used to determine radiative cooling potentials under clear sky conditions, does not account for the cooling potential arising from heat loss to the colder reaches of the atmosphere itself. Here, we show that use of the approximation can lead to >10% underestimation of the cooling potential relative to MODTRAN 6 outputs. We propose a temperature correction to the transmittance-based approximation, which accounts for heat loss to the cold upper atmosphere, and significantly reduces this underestimation, while retaining the advantages of the original model. In light of the widespread and continued use of the transmittance-based model, our results highlight an important source of potential errors in the calculation of clear sky radiative cooling potentials and a means to correct for them.
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Keywords:
radiative cooling; cooling potential; MODTRAN; transmittance model; atmospheric optics; atmospheric irradiance
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MDPI and ACS Style
Mandal, J.; Huang, X.; Raman, A.P. Accurately Quantifying Clear-Sky Radiative Cooling Potentials: A Temperature Correction to the Transmittance-Based Approximation. Atmosphere 2021, 12, 1195. https://doi.org/10.3390/atmos12091195
AMA Style
Mandal J, Huang X, Raman AP. Accurately Quantifying Clear-Sky Radiative Cooling Potentials: A Temperature Correction to the Transmittance-Based Approximation. Atmosphere. 2021; 12(9):1195. https://doi.org/10.3390/atmos12091195
Chicago/Turabian StyleMandal, Jyotirmoy, Xin Huang, and Aaswath P. Raman. 2021. "Accurately Quantifying Clear-Sky Radiative Cooling Potentials: A Temperature Correction to the Transmittance-Based Approximation" Atmosphere 12, no. 9: 1195. https://doi.org/10.3390/atmos12091195
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