Microwave Properties of Ice-Phase Hydrometeors for Radar and Radiometers: Sensitivity to Model Assumptions
Microwave Properties of Ice-Phase Hydrometeors for Radar and Radiometers: Sensitivity to Model Assumptions
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雷达和辐射计冰相水凝物的微波特性：对模型假设的敏感性
DOI：
10.1175/jamc-d-11-0138.1
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发表时间：
2012
影响因子：
3
通讯作者：
G. Skofronick
中科院分区：
文献类型：
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作者：
Benjamin T. Johnson;G. Petty;G. Skofronick
一个简化的框架，评估计算的微波特性，卫星亮度温度和雷达反射率的定性敏感性有关的冰相水凝物的物理特性的假设。考虑的属性包括形状参数的伽玛尺寸分布和熔化的等效质量中值直径D 0，颗粒密度，介电混合公式，和冰的复杂折射率的选择。这些属性进行检查选定的辐射计频率为18.7，36.5，89.0和150.0 GHz和雷达频率在2.8，13.4，35.6和94.0 GHz的现有和计划的遥感仪器一致。被动和主动微波观测的冰粒被发现是非常敏感的D 0的尺寸分布。当几何质量中值直径超过波长的约1 /8时，发现冰体积分数的变化具有类似的大灵敏度。在94 GHz的双向路径集成衰减是潜在的大致密/紧凑的颗粒。分布参数m对任何观测值的影响相对较弱：亮温小于1 - 2 K，有效雷达反射率最大为2.7 dB（仅限S波段）。在麦克斯韦加内特介电混合公式中重新考虑冰和空气的作用会导致微波亮温（;10 K）和雷达反射率（在所有频率上约为2 dB）的显著变化。选择冰的复折射率会导致亮温降低3%-4%的变化。
A simplified framework is presented for assessing the qualitative sensitivities of computed microwave properties, satellite brightness temperatures, and radar reflectivities to assumptions concerning the physical properties of ice-phase hydrometeors. Properties considered included the shape parameterm of a gamma size distribution and the melted-equivalent mass median diameter D0, the particle density, the dielectric mixing formula, and the choice of complex index of refraction for ice. These properties are examined for selected radiometer frequencies of 18.7, 36.5, 89.0, and 150.0 GHz and radar frequencies at 2.8, 13.4, 35.6, and 94.0 GHz—consistent with existing and planned remote sensing instruments. Passive and active microwave observables of ice particles are found to be extremely sensitive to the D0 of the size distribution. Similar large sensitivities are found for variations in the ice volumefractionwheneverthe geometric massmediandiameter exceeds approximately 1 /8th of the wavelength. At 94 GHz the two-way path-integrated attenuation is potentially large for dense/compact particles. The distribution parameter m has a comparatively weak effect on any observable: less than 1‐2 K in brightness temperature and a maximum of 2.7 dB (S band only) in the effective radar reflectivity. Reversal of the roles of ice and air in the Maxwell Garnett dielectric mixing formula leads to a substantial change in both microwave brightness temperature (;10 K) and radar reflectivity (approximately 2 dB across all frequencies).The choice of the complex indexof refraction of ice can produce a 3%‐4% change in the brightness temperature depression.
识别海洋上空 CloudSat 观测中受多重散射影响的剖面
影响因子：
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作者：
Battaglia;J. Haynes;T. L'Ecuyer;C. Simmer
通讯作者：
C. Simmer