Simultaneous observations of tropospheric turbulence from radiosondes using Thorpe analysis and the VHF MU radar
Simultaneous observations of tropospheric turbulence from radiosondes using Thorpe analysis and the VHF MU radar
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DOI：
10.1002/2013rs005355
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发表时间：
2014-11
期刊：
影响因子：
1.6
通讯作者：
H. Luce;R. Wilson;F. Dalaudier;H. Hashiguchi;N. Nishi;Y. Shibagaki;T. Nakajo
中科院分区：
文献类型：
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作者：
H. Luce;R. Wilson;F. Dalaudier;H. Hashiguchi;N. Nishi;Y. Shibagaki;T. Nakajo
本文研究了利用探空仪和甚高频(VHF)雷达资料探测和量化对流层折射率湍流。基于Thorpe排序的气球数据处理方法，最近由Wilson等人开发。(2010、2011和2013)可用于从现场剖面直接识别湍流层。甚高频波段中高层大气雷达(MUR)可以工作在距离成像模式下，以高时间分辨率和高距离分辨率(分别为10 S和几十米量级)探测和监测湍流层。为了交叉验证这些技术，在2011年9月为期3周的野外观测期间，在重崎中高层大气(MU)观测站(北纬34.85°，东经136.15°；日本)同时进行了MUR和RS92SGP Vaisala无线电探空仪观测。通过实例研究和统计分析，研究了气球资料分析中识别出的湍流层在回波功率和纵横比方面的雷达特征。深层(>；~100m)经常与回波功率极大值和弱长宽比有关，这表明两台仪器探测到了相同的各向同性湍流事件。另一些则与各向同性回波功率的相对最小值有关，这可能预示着湍流的后期阶段。强长宽比的范围通常与气球数据中的湍流事件无关，支持各向异性湍流不是垂直增强雷达回波的原因的假设。定量比较了雷达回波功率和由温度变化估计的折射率常数结构Cn2和所选层的附加参数。尽管雷达和气球估计之间有很大的差异，但即使剔除了随CN2高度(湿度和密度)系统下降的原因，结果仍具有统计学意义(相关系数为0.5-0.88)。因此，我们的研究表明，雷达和气球对湍流的观测是相互一致的，并且可以通过这两种技术作为独立的系统来获得对流层湍流的新见解。
This paper deals with the detection and quantification of refractivity turbulence in the troposphere from radiosonde and very high frequency (VHF) band radar data. Balloon data processing methods based on Thorpe sorting and recently developed by Wilson et al. (2010, 2011, and 2013) can be applied for a direct identification of turbulent layers from the in situ profiles. The VHF band mid and upper atmosphere radar (MUR) can be operated in range‐imaging mode for detecting and monitoring turbulent layers at high time and range resolutions (of the order of 10 s and a few tens of meters, respectively). For cross validating the techniques, concurrent MUR and RS92‐SGP Vaisala radiosonde observations were made at the Shigaraki Middle and Upper atmosphere (MU) observatory (34.85°N, 136.15°E; Japan) during a field campaign of 3 weeks in September 2011. The radar signature, in terms of echo power and aspect ratio, of the turbulent layers identified from balloon data analyses is investigated from case studies and statistics. The deep (> ~100 m) layers are very often associated with echo power maxima and weak aspect ratios suggesting that the same events of isotropic turbulence were detected by both instruments. Some others are associated with relative minima of isotropic echo power, possibly indicating a later stage of turbulence. The ranges of strong aspect ratios are generally not associated with turbulent events in the balloon data supporting the hypothesis that anisotropic turbulence is not the cause of vertically enhanced radar echoes. Quantitative comparisons are made between radar echo power and refractive index constant structure Cn2 estimated from temperature variance and additional parameters in the selected layers. Despite a large scatter between the radar and balloon estimates, the results are statistically significant (correlation coefficients ~0.5–0.88) even when the causes of systematic decrease with height of Cn2 (humidity and density) are removed. Our studies therefore demonstrate that radar and balloon observations of turbulence are consistent between each other and that new insights on tropospheric turbulence can be obtained by the two techniques as stand‐alone systems.