| C波段双线偏振天气雷达零度层亮带识别和订正 |
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| 引用本文： | 曹杨,陈洪滨,苏德斌.C波段双线偏振天气雷达零度层亮带识别和订正[J].应用气象学报,2018,29(1):84-96. |
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| 作者姓名： | 曹杨 陈洪滨 苏德斌 |
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| 作者单位： | 1.中国科学院大气物理研究所中层大气和全球环境探测重点实验室, 北京 100029 |
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| 基金项目： | 公益性行业（气象）科研专项（GYHY201106046），国家自然科学基金项目（41275039，41375039），北京市自然科学基金项目（8141002），国家重点研发计划（2017YFA0603504） |
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| 摘 要： | 利用2013年8月北京C波段双偏振多普勒天气雷达体扫数据、探空资料和地面雨量站资料，获得反射率因子垂直廓线（vertical profile of reflectivity，VPR）识别零度层亮带，比较平均反射率因子垂直廓线（mean VPR，MVPR）、显著反射率因子垂直廓线（apparent VPR，AVPR）和显著相关系数垂直廓线（apparent vertical profile of correlation coefficient，AVPCC）3种零度层亮带订正方法的效果，并利用地面雨量站资料进行定量降水估计（quantity precipitation estimation，QPE）验证订正效果。结果表明:采用MVPR和0℃层高度能有效识别零度层亮带，零度层亮带厚度为0.8~1.5 km；经3种方法订正后，零度层亮带影响区得到了不同程度的抑制，其中MVPR法订正效果最差，基本未能减弱零度层亮带的影响，AVPR法和AVPCC法的订正效果较好，明显减弱了零度层亮带影响区的回波强度，订正后回波更均匀。利用地面雨量站数据进行QPE验证表明:经零度层亮带订正后雷达估测的降水与地面雨量站实测降水更接近，也表明AVPR法和AVPCC法效果更好。
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| 关 键 词： | 双偏振天气雷达 零度层亮带识别 零度层亮带订正 |
| 收稿时间： | 2017/6/5 0:00:00 |
| 修稿时间： | 2017/10/9 0:00:00 |
Identification and Correction of the Bright Band Using a C-band Dual Polarization Weather Radar |
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| Cao Yang,Chen Hongbin and Su Debin.Identification and Correction of the Bright Band Using a C-band Dual Polarization Weather Radar[J].Quarterly Journal of Applied Meteorology,2018,29(1):84-96. |
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| Authors: | Cao Yang Chen Hongbin and Su Debin |
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| Institution: | 1.Key Laboratory of Middle Atmosphere and Global Environment Observation, Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing 1000292.University of Chinese Academy of Sciences, Beijing 1000493.Collaborative Innovation Center on Forecast and Evaluation of Meteorological Disasters, Nanjing University of Information Science & Technology, Nanjing 2100444.College of Electronic Engineering, Chengdu University of Information Technology, Chengdu 610225 |
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| Abstract: | The bright band is a layer of enhanced reflectivity due to melting of aggregated snow and ice crystals. The occurrence of a bright band causes significant overestimation in radar-based quantitative precipitation estimation (QPE). The bright band signature can be normally identified from vertical profiles of reflectivity (VPRs) of stratiform precipitation echoes and the freezing level height which is derived from radiosonde data. The VPRs correction is desirable to mitigate the bright band contamination and reduce the overestimation of the radar-based QPE. However, a well-defined bright band bottom, which is critical for the correction of bright band, is sometimes not found in VPRs. Fortunately, polarimetric variables, especially the correlation coefficient, can provide a much better depiction of vertical bright band structure than reflectivity.The volume scanning data of a C-band dual polarization radar from Beijing Meteorological Bureau, radiosonde data and measured rainfall data from ground rain gauge stations are used to test the methodology of the bright band identification and correction. Three bright band correction schemes including mean vertical profile of reflectivity (MVPR), apparent vertical profile of reflectivity (AVPR) and apparent vertical profile of correlation coefficient (AVPCC), which are derived from stratiform precipitation echoes, are applied to the reflectivity field in the given tilt, and radar-based QPEs are derived from the corrected reflectivity field based on traditional Z-R relations. Results indicate that the bright band top, peak and bottom can be easily identified from the volume scanning MVPR and the freezing level height, and most of bright band depths are between 0.8 km and 1.5 km. The AVPR and AVPCC schemes are shown to be more effective in mitigating the bright band contamination and reducing the overestimation of radar-derived QPE associated with the bright band than the MVPR correction. Corrected reflectivity fields are physically continuous in distribution, and the corrected radar-derived QPEs are close to the measured value of ground rain gauge stations. |
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| Keywords: | dual-polarization radar identification of bright band correction of bright band |
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