MULTI-WAVELENGTH RADAR REFLECTIVITY OF HAILSTORMS
MULTI-WAVELENGTH RADAR REFLECTIVITY OF HAILSTORMS
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冰雹的多波长雷达反射率
DOI：
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发表时间：
1961
期刊：
影响因子：
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通讯作者：
F. Ludlam
中科院分区：
文献类型：
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作者：
D. Atlas;F. Ludlam
根据指数大小光谱中冰雹上升气流中存在的粒子的雷达反射率 Ze 进行计算。反射率根据雷达波长以及颗粒是湿的还是干的而显着变化。在严重的风暴中，高空可能会观察到非常强烈的回声。部分参考一个特定的例子，表明只有当负责的颗粒是尺寸几乎均匀的大的干燥冰雹时，它在较短波长（Ze ± 107 mm6 m-3）下的大小以及其强度随波长的变化才能合理地解释。大石头的干燥和排序归因于通过风切变落到上升气流之外，而回波强度的降低则归因于它们重新进入上升气流和湿润。地面冰雹的可能性和大小似乎是通过高空 3 cm 处的回波强度来指示的，在 4·7 cm 处则不太敏感，但在 10 cm 处则不然。测量多个波长的回波强度有助于研究严重风暴。
Computations are made of the radar reflectivity Ze of particles present in hailstorm updraughts in exponential size spectra. The reflectivity varies substantially according to the radar wavelength and according to whether the particles are wet or dry. In severe storms a very strong echo may be observed aloft. Partly by reference to a particular example it is shown that its magnitude at the shorter wavelengths (Ze ± 107 mm6 m–3), and the variation of its intensity with wavelength, can reasonably be explained only if the responsible particles are large dry hailstones of almost uniform size. The dryness and sorting of the large stones is attributed to fall outside the updraught through a wind shear, and the decrease of echo intensity lower down to their re-entry into the updraught and wetting. It appears that the likelihood and size of hail at the ground are indicated by echo intensity aloft at 3 cm, and less sensitively at 4·7 cm, but not at 10 cm. Measurements of echo intensity at several wavelengths are helpful in the study of severe storms.