A modified scheme that parameterizes depositional growth of ice crystal: A modeling study of pre-summer torrential rainfall case over Southern China

• Published in: Atmospheric research 2014-03, Vol.138, p.293-300
• Main Authors: Shen, Xinyong, Huang, Wei, Qing, Tao, Huang, Wenyan, Li, Xiaofan
• Format: Article
• Language: English
• Subjects: Cloud-resolving model simulation; Depositional growth of cloud ice; Earth, ocean, space; Exact sciences and technology; External geophysics; Ice crystal concentration; Meteorology; Parameterization scheme; Storms, hurricanes, tornadoes, thunderstorms; Water in the atmosphere (humidity, clouds, evaporation, precipitation)
• ISSN: 0169-8095; 1873-2895
• DOI: 10.1016/j.atmosres.2013.11.020

Depositional growth of cloud ice is estimated and its parameterization schemes are compared through the two-dimensional cloud-resolving modeling analysis of pre-summer heavy rainfall over southern China. Hsie et al. (1980) and Krueger et al. (1995) developed parameterization schemes to calculate depositional growth of cloud ice by estimating the growth timescale under the assumption that the ice crystal concentration is independent of crystal size. A new scheme is proposed by Zeng et al. (2008) under the assumption that the ice crystal concentration is proportional to the mass of ice crystal. Hsie's and Krueger's schemes produce small amount of cloud ice similar to what Zeng's scheme with low ice crystal concentration does. When ice crystal concentration is increased to a high value in Zeng's scheme, the simulation generates anomalous depositional growth of cloud ice and thus anomalous area expansion of stratiform rainfall. Zeng's scheme is modified by changing radius of base ice crystal from 0 to 40μm in the calculation of depositional growth of cloud ice. The modified scheme with high ice crystal concentration greatly reduces growth of cloud ice and thus fractional coverage of stratiform rainfall. •Schemes using timescale and low ice concentration produce a low ice amount.•High ice concentration leads to anomalous depositional growth of ice crystal.•A modified scheme significantly reduces depositional growth of ice crystal.