Estimating Microphysics Properties in Ice-Dominated Clouds from Airborne Ka–W-band Dual-Wavelength Ratio Reflectivity Factor in Close Proximity to In Situ Probes
Estimating Microphysics Properties in Ice-Dominated Clouds from Airborne Ka–W-band Dual-Wavelength Ratio Reflectivity Factor in Close Proximity to In Situ Probes
复制标题
利用机载 Ka-W 波段双波长比反射率因子估算以冰为主的云中的微物理特性（靠近原位探头）
DOI：
10.1175/jtech-d-21-0147.1
复制
发表时间：
2022
影响因子：
2.2
通讯作者：
Rauber, Robert M.
中科院分区：
文献类型：
--
作者：
Grasmick, Coltin;Geerts, Bart;French, Jeffrey R.;Haimov, Samuel;Rauber, Robert M.
云中冻结的水凝物的性质仍然难以远程感知。数量浓度，分布形状，冰粒密度和冰水含量的估计是必不可少的云过程连接到地面降水。双频雷达已经取得了进展，但由于缺乏与雷达测量相配合的粒子成像和尺寸观测，验证一直很困难。这里，使用的数据从两个机载剖面（向上和向下）雷达，W波段怀俄明州云雷达和Ka波段剖面雷达，允许Ka-W波段双波长比（DWR）的配置文件。这架飞机（怀俄明州国王航空大学）还携带了一套现场云和降水探测器。这种安排对于将“飞行高度”DWR（飞行高度以下和以上雷达门的平均值）与现场光学阵列探头测量的冰颗粒尺寸分布以及最小雪颗粒密度和冰水含量等整体特性联系起来是最佳的。这种比较揭示了DWR和冰粒中位体积直径之间的密切关系。DWR值的最佳范围确保了最高的检索置信度，由雷达的相对校准和DWR饱和度限定，在这里发现约为2.5-7.5 dB。DWR定义的尺寸分布形状与Mie散射模型和实验质量直径关系，以测试反演的冰颗粒浓度和冰水含量。与飞行水平云探测数据的比较表明，良好的性能，允许微物理解释的垂直雷达断面的其余部分。
Properties of frozen hydrometeors in clouds remain difficult to sense remotely. Estimates of number concentration, distribution shape, ice particle density, and ice water content are essential for connecting cloud processes to surface precipitation. Progress has been made with dual-frequency radars, but validation has been difficult because of lack of particle imaging and sizing observations collocated with the radar measurements. Here, data are used from two airborne profiling (up and down) radars, the W-band Wyoming Cloud Radar and the Ka-band Profiling Radar, allowing for Ka–W-band dual-wavelength ratio (DWR) profiles. The aircraft (the University of Wyoming King Air) also carried a suite of in situ cloud and precipitation probes. This arrangement is optimal for relating the “flight-level” DWR (an average from radar gates below and above flight level) to ice particle size distributions measured by in situ optical array probes, as well as bulk properties such as minimum snow particle density and ice water content. This comparison reveals a strong relationship between DWR and the ice particle median-volume diameter. An optimal range of DWR values ensures the highest retrieval confidence, bounded by the radars’ relative calibration and DWR saturation, found here to be about 2.5–7.5 dB. The DWR-defined size distribution shape is used with a Mie scattering model and an experimental mass–diameter relationship to test retrievals of ice particle concentration and ice water content. Comparison with flight-level cloud-probe data indicate good performance, allowing microphysical interpretations for the rest of the vertical radar transects.