Doppler radar investigation of Hawaiian rain
Doppler radar investigation of Hawaiian rain
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多普勒雷达对夏威夷降雨的调查
DOI：
10.1111/j.2153-3490.1967.tb01498.x
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发表时间：
1967
期刊：
影响因子：
2
通讯作者：
R. Rogers
中科院分区：
文献类型：
--
作者：
R. Rogers
多普勒雷达对夏威夷多个降雨回波的测量表明，对流的数量不一，垂直空气速度从某些情况下无法测量的小值到对流较多的情况下的7米/秒不等。当在高度与时间的坐标上绘制时，表现出弱垂直运动的回波通常具有层状外观：信号强度和多普勒速度的轮廓趋于近似水平。在这些情况下，强度随高度降低，垂直梯度高达20 db/km并不罕见。在回波表现出强烈的垂直空气运动，信号强度，回波深度和地面降雨率往往较高。雷达反射率因子高达105 mm 6 /m3。虽然高度-时间模式显示较弱的上升气流速度的回波秩序，有一种趋势的领先（上坡）的对流回波的一部分比尾部更活跃。随着回波进一步向上坡行进，它们的特征趋于变得更加层状。事实上，中雨有时可以从浅，层状云，结合在这些情况下观察到的强垂直反射率梯度，表明在夏威夷地形云的降水过程的高效率。对流回波的观测清楚地表明对流运动增强了这一过程。DOI：10.1111/j.2153-3490.1967.tb01498.x
Doppler radar measurements in a number of Hawaiian rain echoes indicated a variable amount of convection, with vertical air velocities ranging from unmeasurably small values in some cases to values of 7 m/sec in the more convective cases. The echoes exhibiting weak vertical motions usually had a stratiform appearance when plotted on coordinates of height versus time: contours of signal intensity and Doppler velocity tended to be approximately horizontal. The intensity decreased with altitude in these cases, and vertical gradients as strong as 20 db/km were not uncommon. In the echoes exhibiting strong vertical air motions, signal intensities, echo depth, and surface rainfall rate tended to be higher. Radar reflectivity factors as high as 10 5 mm 6 /m 3 were observed. Although height-time patterns revealed less order than in the echoes with weak updraft velocities, there was a tendency for the leading (upslope) portion of a convective echo to be more active than the trailing portion. As echoes progressed further upslope they tended to become more stratiform in character. The fact that moderate rain could at times fall from shallow, stratiform clouds, taken in conjunction with the strong vertical reflectivity gradients observed in these cases, indicates a high efficiency of the precipitation process in Hawaiian orographic clouds. The observations in convective echoes clearly demonstrate that convective motions enhance the process. DOI: 10.1111/j.2153-3490.1967.tb01498.x