Aircraft and dual polarization radar observations of hydrometeors in light stratiform precipitation
Aircraft and dual polarization radar observations of hydrometeors in light stratiform precipitation
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轻层状降水中水凝物的飞机和双偏振雷达观测
DOI：
10.1002/qj.49711347605
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发表时间：
2007
影响因子：
8.9
通讯作者：
G. Cox
中科院分区：
文献类型：
--
作者：
M. Bader;S. Clough;G. Cox
提出了一个研究冰相微物理结构与微分反射率关系的案例研究。讨论了轻微降水中冰晶类型的分布，并证明其与单个降水下降条纹的理论模型一致。研究发现，颗粒特征反映了与弱风切变下落相关的尺寸和类型分类，以及在下落条纹内不同温度和湿度条件下的生长。
将观察到的差异反射率与原位颗粒测量进行比较，并证明高值与平面晶体结构的关联。研究发现，颗粒尺寸分布对雷达回波有显着影响，特别是通过形状不定的大颗粒的模糊效应。这种效应引起了微分反射率的相对变化，人们发现这种变化与单分散模型的预测不同。特别是，在这种情况下，发现低密度的大树枝状晶体与较致密的板状晶体相比具有更强的特征，从理论研究来看，板状晶体可能会产生最大的微分反射率。由于层状条件下的这些复杂因素，得出的结论是，在缺乏现场测量或其他支持数据的情况下，必须非常谨慎地解释差分反射率数据。
A case study investigating the relationship of ice phase microphysical structure to differential reflectivity is presented. the distribution of ice crystal types in light precipitation is discussed and shown to agree with a theoretical model of an individual precipitation fallstreak. the particle characteristics were found to reflect sorting by size and type associated with fall through weak wind shear as well as growth in regimes of varying temperature and humidity within the fallstreak.
The observed differential reflectivities were compared with the in situ particle measurements and the association of high values with planar crystal structures demonstrated. the particle size distribution was found to have a marked influence on radar returns, particularly through the obscuring effects of large particles of indefinite shape. This effect gave rise to relative variations of differential reflectivity which were found to differ from the predictions of monodisperse models. In particular large dendritic crystals of low density were found in this case to be associated with stronger signatures than denser plate-like crystals which from theoretical studies might be expected to produce the greatest differential reflectivity. Because of these complicating factors under stratiform conditions it was concluded that differential reflectivity data must be interpreted with considerable caution in the absence of in situ measurements or other supporting data.