Supercooled liquid water is present in mixed-phase and liquid-only clouds in the polar regions and at high altitudes globally. The radiative properties of these clouds depend on the complex refractive index (CRI) of liquid water, which laboratory measurements have shown to be temperature dependent. Despite this, most radiative transfer and climate models typically use CRI based on room-temperature liquid water. Radiative transfer calculations have shown that this has important consequences for the infrared radiance of clouds containing supercooled liquid water (Rowe et al. 2013). Despite this, most radiative transfer and climate models typically use CRI based on room-temperature liquid water.

To address this need, we have computed temperature-dependent single-scattering parameters for computing radiative transfer through supercooled liquid cloud at temperatures of 240, 253, 263, and 273 K. At 300 K, we suggest the single scattering parameters of Bertie and Lan, rather than that of Downing and Williams. Please note that the single-scattering parameters have been updated. A publication is pending, and the values here should be updated by summer 2020, so please check back then.

• Liquid water SSP at 240 K (Rowe et al. 2013; 2019)
• Liquid water SSP at 253 K (Rowe et al. 2013; 2019)
• Liquid water SSP at 263 K (Rowe et al. 2013; 2019)
• Liquid water SSP at 273 K (Rowe et al. 2013; 2019)
• Liquid water SSP at 298 K (Rowe et al. 2013; 2019; Bertie and Lan 1996)
• Liquid water SSP at 300 K (Rowe et al. 2013; 2019; Downing and Williams 1975)
• Water ice sphere SSP at 266 K (Rowe et al. 2013; 2019; Warren and Brandt 2008)
• Water ice rough solid column SSP (Yang et al. 2013; Rowe et al. 2019)

Please acknowledge use of these datasets in publications.

References:

Rowe, P. M., Cox, C., Neshyba, S., & Walden, V. P. (2019). Toward autonomous surface-based infrared remote sensing of polar clouds: retrievals of cloud optical and microphysical properties. Atmospheric Measurement Techniques, 12(9), 5071–5086. http://doi.org/10.5194/amt-12-5071-2019

Rowe, P. M., Neshyba, S., & Walden, V. P. (2013). Radiative consequences of low-temperature infrared refractive indices for supercooled water clouds. Atmospheric Chemistry and Physics, 13(23), 11925–11933.

Bertie, J. E., & Lan, Z. (1996). Infrared Intensities of Liquids XX: The Intensity of the OH Stretching Band of Liquid Water Revisited, and the Best Current Values of the Optical Constants of H2O(l) at 25°C between 15,000 and 1 cm-1. Applied Spectroscopy, 50(8), 1047–1057. http://doi.org/10.1366/0003702963905385.

Downing, H. D., & Williams, D. (1975). Optical constants of water in the infrared. Journal of Geophysical Research, 80(12), 1656–1661.

Warren, S. G., & Brandt, R. E. (2008). Optical constants of ice from the ultraviolet to the microwave: A revised compilation. Journal of Geophysical Research, 113(D14), D14220. http://doi.org/10.1029/2007JD009744.

Yang, P., Bi, L., Baum, B. A., Liou, K. N., Kattawar, G. W., Mishchenko, M. I., and Cole, B. (2013). Spectrally Consistent Scattering, Absorption, and Polarization Properties of Atmospheric Ice Crystals at Wavelengths from 0.2 to 100 μm. J. Atmos. Sci., 70, 330–347, doi:10.1175/JAS-D-12-039.1.

Acknowledgements:

This work was funded by NSF Office of Polar Programs award 1543236 and NSF CHE-1807898.