On the consistency of 2-D video disdrometers in measuring microphysical parameters of solid precipitation
On the consistency of 2-D video disdrometers in measuring microphysical parameters of solid precipitation
复制标题
二维视频测距仪测量固体降水微物理参数的一致性研究
DOI：
10.5194/amt-8-3251-2015
复制
发表时间：
2015
影响因子：
3.8
通讯作者：
J. Tschiersch
中科院分区：
文献类型：
--
作者：
F. Bernauer;K. Hürkamp;W. Rühm;J. Tschiersch
抽象的。降水的详细表征和分类是大气研究的一项重要任务。线扫描二维视频测速仪设备非常适合降雨观测。对通过仪器敏感区域的每个水凝物采取的两个正交视图使这些设备特别适合非对称固体水凝物的详细表征。然而，在固体降水的情况下，必须考虑与匹配算法相关的问题，并且用户在分析尺寸和形状描述符时必须意识到有限的空间分辨率。这项工作的目的是阐明二维视频测速仪在从单张记录的图片中获取尺寸、速度和形状参数方面的潜力。强调需要实施适合混合相和固相沉淀的匹配算法，作为数据评估的重要步骤。为此，使用实心钢球和不规则形状的聚苯乙烯泡沫塑料颗粒进行了简单的可重复实验。在38个真实降雪案例中测试了形状参数测量的自洽性。结果发现，只有对于大于 1 毫米的颗粒，才可能实现相对标准偏差小于 5% 的可靠尺寸和形状表征。对于 0.5 至 1.0 毫米之间的颗粒，体积的相对标准偏差可增长至 22%，尺寸参数的相对标准偏差可增长至 17%，形状描述符的相对标准偏差可增长至 14%。通过使用聚苯乙烯泡沫塑料颗粒的可重复实验来测试适应的匹配算法，发现失配概率小于 3%。对于真实固相沉淀情况下的形状参数测量，2-DVD 显示了自洽行为。
Abstract. Detailed characterization and classification of precipitation is an important task in atmospheric research. Line scanning 2-D video disdrometer devices are well established for rain observations. The two orthogonal views taken of each hydrometeor passing the sensitive area of the instrument qualify these devices especially for detailed characterization of nonsymmetric solid hydrometeors. However, in case of solid precipitation, problems related to the matching algorithm have to be considered and the user must be aware of the limited spatial resolution when size and shape descriptors are analyzed. Clarifying the potential of 2-D video disdrometers in deriving size, velocity and shape parameters from single recorded pictures is the aim of this work. The need of implementing a matching algorithm suitable for mixed- and solid-phase precipitation is highlighted as an essential step in data evaluation. For this purpose simple reproducible experiments with solid steel spheres and irregularly shaped Styrofoam particles are conducted. Self-consistency of shape parameter measurements is tested in 38 cases of real snowfall. As a result, it was found that reliable size and shape characterization with a relative standard deviation of less than 5 % is only possible for particles larger than 1 mm. For particles between 0.5 and 1.0 mm the relative standard deviation can grow up to 22 % for the volume, 17 % for size parameters and 14 % for shape descriptors. Testing the adapted matching algorithm with a reproducible experiment with Styrofoam particles, a mismatch probability of less than 3 % was found. For shape parameter measurements in case of real solid-phase precipitation, the 2-DVD shows self-consistent behavior.