Dependency of stratiform precipitation on a two-moment cloud microphysical scheme in mid-latitude squall line
Dependency of stratiform precipitation on a two-moment cloud microphysical scheme in mid-latitude squall line
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DOI：
10.1016/j.atmosres.2013.12.009
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发表时间：
2013-08
影响因子：
5.5
通讯作者：
Y. Baba;Keiko Takahashi
中科院分区：
文献类型：
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作者：
Y. Baba;Keiko Takahashi
利用全一阶矩、全二阶矩和部分二阶矩云微物理方案，研究了中纬度飑线层状云降水对二阶矩云微物理方案的影响。结果表明，两时刻方案对降水的影响与前人的研究结果一致，但对冰水组分（冰粒）的影响取决于两时刻方案，后者能增强对流区的后向浮力通量，并能增强对流区的后向浮力通量。研究发现，云水和云冰两时刻方案的使用对层状降水形成的直接影响较小，但通过改变大液体和冰粒的源数浓度来间接影响降水。两个时刻的处理，而不是雪也被发现有很大的影响，层状降水通过融化过程。由其尺度分布变化产生的水平窄、垂直渐变的<$球融化廓线，抑制了对流区的对流上升气流，从而增加了对流区到层状区的水平后浮力，促进了冰水种类的增长，导致层状降水的增加。为了模拟这些特征，需要对进行二阶矩处理或考虑粒度分布变化的截距参数诊断模型。
Dependency of stratiform precipitation on a two-moment cloud microphysical scheme in mid-latitude squall line is investigated, using full one-moment, full two-moment and partial two-moment schemes. The results show that the effect of two-moment scheme for rain is consistent with those presented in preceding studies, but the effect is found to be dependent on two-moment scheme for ice water species (ice particles) which enhanced detrainment in convective region and increased rearward buoyancy fluxes. Use of the two-moment scheme for cloud water and cloud ice is found to have less direct impact on the formation of stratiform precipitation, but indirectly affects the precipitation by changing source number concentration of large liquid and ice particles. Two-moment treatment for graupel rather than snow is also found to have great impact on stratiform precipitation through the melting process. The horizontally narrow and vertically gradual graupel melting profile originated from its size distribution change causes suppression to the convective updraft in convective region, and thus increases horizontal rearward buoyancy from the convective to stratiform regions with enhanced growth of ice water species, resulting in an increase in stratiform precipitation. To simulate these features, two-moment treatment for graupel or diagnostic model for graupel intercept parameter considering size distribution change is required.