Cober (2004), Single-scattering properties of mixed-phase Arctic clouds at solar wavelengths: Impacts on radiative transfer

• Main Authors: Greg M. Mcfarquhar, Stewart G. Cober
• Other Authors: The Pennsylvania State University CiteSeerX Archives
• Format: Text
• Language: English
• Subjects: Arctic; albedo
• Online Access: http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.492.4683; http://curry.eas.gatech.edu/MAP/pdf/mcfarquharcober2004.pdf

In situ observations of the sizes, shapes, and phases of Arctic clouds were obtained during the First International Satellite Cloud Climatology Project Regional Experiment (FIRE) Arctic Clouds Experiment (ACE). These particle distributions were then combined with a library of single-scattering properties, calculated using Mie theory and improved geometric ray optics, to determine the corresponding single-scattering properties (single-scattering albedo v0, phase function, and asymmetry parameter g) at solar wavelengths. During FIRE-ACE, mixed-phase clouds, where both water and ice were detected in 30 s of flight track, corresponding to 3.0-km horizontal extent, were observed in 33 % of clouds. Because supercooled water drops generally dominate mass contents of these mixed-phase clouds, there is no statistically significant difference in the distributions of single-scattering prop-erties of mixed-phase clouds compared to liquid-phase clouds, whereas those of ice crystals differ significantly. The average g for all mixed-phase clouds at visible wavelengths is 0.8556.005, similar to 0.8636.007 computed for water clouds, but higher than 0.7676.007 computed for ice clouds. Differences in g and v0 between mixed-and ice-phase clouds for near-infrared bands are also noted, whereas they are similar for mixed- and liquid-phase clouds. Single-scattering properties computed using observations of mixed-phase clouds differ by more than 10 % on