Open AccessEstimating the Ice Crystal Enhancement Factor in the Tropics
Author(s) -
Xiping Zeng,
WeiKuo Tao,
Toshihisa Matsui,
Shaocheng Xie,
S. Lang,
Minghua Zhang,
David Oc. Starr,
Xiaowen Li
Publication year - 2011
Publication title -
journal of the atmospheric sciences
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.853
H-Index - 173
eISSN - 1520-0469
pISSN - 0022-4928
DOI - 10.1175/2011jas3550.1
Subject(s) - ice crystals , tropics , atmospheric sciences , environmental science , entrainment (biomusicology) , climatology , latitude , cloud physics , meteorology , cloud computing , geology , physics , geodesy , fishery , rhythm , acoustics , biology , computer science , operating system
The ice crystal enhancement (IE) factor, defined as the ratio of the ice crystal to ice nuclei (IN) number concentrations for any particular cloud condition, is needed to quantify the contribution of changes in IN to global warming. However, the ensemble characteristics of IE are still unclear. In this paper, a representation of the IE factor is incorporated into a three-ice-category microphysical scheme for use in long-term cloud-resolving model (CRM) simulations. Model results are compared with remote sensing observations, which suggest that, absent a physically based consideration of how IE comes about, the IE factor in tropical clouds is about 103 times larger than that in midlatitudinal ones. This significant difference in IE between the tropics and middle latitudes is consistent with the observation of stronger entrainment and detrainment in the tropics. In addition, the difference also suggests that cloud microphysical parameterizations depend on spatial resolution (or subgrid turbulence parameterizations within CRMs).