Measurement of Attenuation with Airborne and Ground-Based Radar in Convective Storms Over Land and Its Microphysical Implications
Measurement of Attenuation with Airborne and Ground-Based Radar in Convective Storms Over Land and Its Microphysical Implications
复制标题
机载和地基雷达对陆地对流风暴衰减的测量及其微物理意义
DOI：
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发表时间：
2013
期刊：
影响因子：
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通讯作者：
R. C. Srivastava
中科院分区：
文献类型：
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作者：
L. Tian;G. Heymsfield;R. C. Srivastava
利用机载X波段多普勒雷达（EDOP）和NCAR S波段偏振雷达（S-Pol）的观测资料，对地面参考技术（SRT）的路径积分衰减（PIA）测量和深对流风暴衰减研究进行了评价。EDOP在20公里的高度飞行，使用最低点波束和前向波束。研究发现，在陆地上，地面散射截面在最低点入射时变化很大，但在前向入射时相对稳定。它的结论是，测量由前向光束提供了一个可行的技术，用于测量PIA使用SRT。本文用双波长方法计算了两次强对流天气的峰值衰减系数垂直廓线。使用测得的多普勒速度，在两个波长的反射率，差分反射率，和估计的衰减系数，它表明，过冷液滴和（干）冰粒可能共存的融化水平以上的上升气流和水涂层部分融化的冰粒可能有助于高衰减低于融化水平。
Observations by the airborne X-band Doppler radar (known as EDOP) and the NCAR S-band polarimetric (S-Pol) radar from two field experiments are used to evaluate the surface reference technique (SRT) for measuring the path-integrated attenuation (PIA) and to study attenuation in deep convective storms. The EDOP, flying at an altitude of 20 km, uses a nadir beam and a forward-pointing beam. It is found that over land the surface scattering cross section is highly variable at nadir incidence but is relatively stable at forward incidence. It is concluded that measurement by the forward beam provides a viable technique for measuring PIA using the SRT. Vertical profiles of peak attenuation coefficient are derived in two deep convective storms by the dual-wavelength method. Using the measured Doppler velocity, the reflectivities at the two wavelengths, the differential reflectivity, and the estimated attenuation coefficients, it is shown that supercooled drops and (dry) ice particles probably coexisted above the melting level in regions of updraft and that water-coated partially melted ice particles probably contributed to high attenuation below the melting level.