The Accuracy of Radar Estimates of Ice Terminal Fall Speed from Vertically Pointing Doppler Radar Measurements
The Accuracy of Radar Estimates of Ice Terminal Fall Speed from Vertically Pointing Doppler Radar Measurements
复制标题
通过垂直指向多普勒雷达测量雷达估算冰端下落速度的准确性
DOI：
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发表时间：
2011
期刊：
影响因子：
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通讯作者：
C. Williams
中科院分区：
文献类型：
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作者：
A. Protat;C. Williams
本文利用不同频率(50 MHz和2835 MHz)的多普勒云雷达观测资料，研究了水流星的末端落体速度和热带冰云中空气的垂直运动，并评价了单台垂直指向的云雷达反演这两个参数的统计方法。对于观测到的垂直空气运动，发现冰云中的平均垂直空气速度平均较小，这与终端下落速度反演方法所假定的一样。平均垂直气流运动在融化层(5公里高度)到6.3公里高度之间是略负的(下沉气流)，在该高度以上是正的(上升气流)，在7.7公里和9.7公里高度有两个6和7厘米的峰值S−1。对于所反演的水流星终端落体速度，发现在窄反射率范围内的终端落体速度的变异性通常在使用冰云微物理反演的终端落体速度的可接受的不确定度之内。本研究还评估了该系统的性能。
AbstractDoppler radar measurements at different frequencies (50 and 2835 MHz) are used to characterize the terminal fall speed of hydrometeors and the vertical air motion in tropical ice clouds and to evaluate statistical methods for retrieving these two parameters using a single vertically pointing cloud radar. For the observed vertical air motions, it is found that the mean vertical air velocity in ice clouds is small on average, as is assumed in terminal fall speed retrieval methods. The mean vertical air motions are slightly negative (downdraft) between the melting layer (5-km height) and 6.3-km height, and positive (updraft) above this altitude, with two peaks of 6 and 7 cm s−1 at 7.7- and 9.7-km height. For the retrieved hydrometeor terminal fall speeds, it is found that the variability of terminal fall speeds within narrow reflectivity ranges is typically within the acceptable uncertainties for using terminal fall speeds in ice cloud microphysical retrievals. This study also evaluates the performan...