Reducing the Biases in Simulated Radar Reflectivities from a Bulk Microphysics Scheme: Tropical Convective Systems
Reducing the Biases in Simulated Radar Reflectivities from a Bulk Microphysics Scheme: Tropical Convective Systems
复制标题
通过体微物理方案减少模拟雷达反射率的偏差：热带对流系统
DOI：
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发表时间：
2011
期刊：
影响因子：
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通讯作者：
Yaping Li
中科院分区：
文献类型：
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作者：
S. Lang;W. Tao;Xiping Zeng;Yaping Li
摘要目前云解析模型中使用的许多体微物理方案都存在一个众所周知的偏差，即在模拟对流系统中对流层中层和上层容易产生过大的反射率值（例如 40 dBZ）。戈达德积云系综模型中基于拉特利奇和霍布斯的体微物理方案经过修改，以减少这种偏差并改善现实情况。修改包括降低雪/霰雨和积雪云冰的效率；将较少的霜雪转化为霰；允许雪/霰升华；添加雾凇分裂、浸没冷冻和接触成核；用 Meyers 等人的公式替换了活化冰核的 Fletcher 公式；在饱和度调整中允许冰过饱和；考虑云冰向雪生长过程中的环境相对湿度；并添加/考虑云冰坠落速度。此外，还添加了雪/霰的尺寸映射方案作为温度和米的函数...
AbstractA well-known bias common to many bulk microphysics schemes currently being used in cloud-resolving models is the tendency to produce excessively large reflectivity values (e.g., 40 dBZ) in the middle and upper troposphere in simulated convective systems. The Rutledge and Hobbs–based bulk microphysics scheme in the Goddard Cumulus Ensemble model is modified to reduce this bias and improve realistic aspects. Modifications include lowering the efficiencies for snow/graupel riming and snow accreting cloud ice; converting less rimed snow to graupel; allowing snow/graupel sublimation; adding rime splintering, immersion freezing, and contact nucleation; replacing the Fletcher formulation for activated ice nuclei with that of Meyers et al.; allowing for ice supersaturation in the saturation adjustment; accounting for ambient RH in the growth of cloud ice to snow; and adding/accounting for cloud ice fall speeds. In addition, size-mapping schemes for snow/graupel were added as functions of temperature and m...