Effects of ice particle shape and orientation on polarized microwave radiation for off‐nadir problems
Effects of ice particle shape and orientation on polarized microwave radiation for off‐nadir problems
复制标题
冰粒形状和方向对偏低点问题的偏振微波辐射的影响
DOI：
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发表时间：
1998
期刊：
影响因子：
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通讯作者：
H. Czekala
中科院分区：
文献类型：
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作者：
H. Czekala
研究了高空云层（9 ~ 10 km高度）的冰晶形状和方向对地球大气微波辐射角分布和极化状态的影响。在200 GHz下，研究了非球面形状对两种不同形状的潜在影响：扁球体和长条形球体，其优先取向为对称轴，宽高比分别为5.0和0.2。结果表明，形状和取向对总强度和极化态都有很强的影响。接近水平的传播方向对对流层/平流层下微波边缘探测研究具有特殊的意义。虽然所提出的计算没有考虑具有六边形粒子的实际冰云，并且没有明确考虑边缘探测几何形状，但在大离底角的情况下获得的结果得出这样的结论：粒子形状，特别是在具有首选取向轴的粒子的情况下，对强度（高达15 K）和极化差（高达30 K）有显著影响。
The effect of ice crystal shape and orientation from high altitude clouds (9 to 10 km height) on the angular distribution and state of polarization of microwave radiation emerging from the earth's atmosphere is investigated. The potential effects of nonspherical shapes are studied at 200 GHz and for two different shapes: Oblate and prolate spheroids with a preferred orientation of the axis of symmetry and an aspect ratio of 5.0 and 0.2, respectively. The results show strong effects of shape and orientation on both the total intensity and polarization state. Propagation directions close to the horizontal are of special interest to troposphere/lower stratosphere microwave limb‐sounding investigations. Although the presented calculations do not consider realistic ice clouds with hexagonal particles and the limb sounding geometry is not explicitly taken into account, the results obtained for large off‐nadir angles lead to the conclusion that particle shapes, especially in case of particles with preferred axis of orientation, have a significant effect on intensity (up to 15 K) and polarization difference (up to 30 K).