张哲,师宇,王咏薇,刘磊,胡非.基于风廓线雷达的对流边界层高度的确定.气象科学,2019,39(3):359-367 ZHANG Zhe,SHI Yu,WANG Yongwei,LIU Lei,HU Fei.Determination of connective boundary layer height based on wind profile radar.Journal of the Meteorological Sciences,2019,39(3):359-367
基于风廓线雷达的对流边界层高度的确定
Determination of connective boundary layer height based on wind profile radar
投稿时间:2017-10-23  修订日期:2018-02-22
DOI:10.3969/2018jms.0015
中文关键词:  边界层高度  风廓线雷达  折射率结构常数
英文关键词:boundary layer height  wind profile radar  refractive index structure constant
基金项目:国家重点研发计划(2016YFC0208802;2017YFC0209600);国家自然科学基金资助项目(41675012)
作者单位E-mail
张哲 中国科学院 大气物理研究所/大气边界层物理和大气化学国家重点实验室, 北京 100029
中国科学院大学, 北京 100049 
 
师宇 中国科学院 大气物理研究所/大气边界层物理和大气化学国家重点实验室, 北京 100029
中国科学院大学, 北京 100049 
 
王咏薇 南京信息工程大学 大气物理学院, 南京 210044  
刘磊 中国科学院 大气物理研究所/大气边界层物理和大气化学国家重点实验室, 北京 100029  
胡非 中国科学院 大气物理研究所/大气边界层物理和大气化学国家重点实验室, 北京 100029
中国科学院大学, 北京 100049 
hufei@mail.iap.ac.cn 
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中文摘要:
      大气边界层高度对于天气、气候和大气污染研究是一个至关重要的参量。对流边界层(Convective Boundary Layer,CBL)顶部的夹卷过程造成温度和湿度垂直梯度增强,导致这一层的折射率结构常数Cn2变高。Cn2的这种垂直分布特征经常被用来定位出CBL高度Zi。本文利用2010年7-8月天津大港的风廓线雷达数据推断出CBL高度Zi,对于多重Cn2峰值或不明确的Cn2峰值,本文改进了对Zi的测定,分别讨论了Cn2最大后向散射法与Cn2和垂直速度方差(σw2)相结合的新方法的适用性。研究显示:(1) Cn2廓线具有单峰时,最大后向散射强度法能正确估计CBL高度,这种情况往往对应的是晴天。CBL上存在的残留层或云层引起的温湿起伏变化导致Cn2廓线具有双峰甚至多峰时,最大后向散射强度法可能会错误估计CBL高度;(2)Cn2σw2结合的方法不仅与晴天时Cn2最大后向散射法有较好的一致性,而且可以将CBL造成的Cn2峰值从云层造成的Cn2峰值中区分出来,从而正确估计CBL高度;(3)一般而言,对流边界层中存在有明显的、破碎或者分散不明显的云时,Cn2σw2结合的方法都能较好地识别出CBL对应的Cn2峰值。但由于边界层中的情况极为复杂,Cn2σw2结合法也会因不同的原因而错误估计CBL高度。
英文摘要:
      The atmospheric boundary layer height is a critical parameter for studies of weather, climate and air pollution. The entrainment process at the top of the Convective Boundary Layer (CBL) results in an increased vertical gradient of temperature and humidity, thus enhancing the refractive index structure constant Cn2 for this layer. This vertical distribution feature of Cn2 is often used to locate the CBL height Zi. In this paper, the CBL height Zi is deduced from the wind profile radar data of Grand Port District of Tianjin from July to August in 2010. For the multiple or unclear Cn2 peaks, this paper improves the measurement of Z, and discusses the applicability of the maximum backscattered intensity method and the method combining Cn2 and the vertical velocity variance σw2. The results show that:(1) When the Cn2 profile has a single peak, the maximum backscattered intensity method can correctly estimate the height of CBL. This situation often corresponds to a sunny day. The maximum backscattered intensity method may incorrectly estimate the height of CBL when the temperature and humidity fluctuation caused by the residual layer or the cloud layer in the CBL leads to a Cn2 profile with double peaks or even multiple peaks; (2) The method combining Cn2 and σw2 is not only consistent with the maximum backscattered method at sunny days, but also distinguishes the Cn2 peak caused by CBL from the Cn2 peak caused by the cloud layer, thus correctly estimating the CBL height; (3) In general, the method combining Cn2 and σw2 can well identify the Cn2 peak corresponding to CBL when there are obvious, broken or undisclosed clouds in the convective boundary layer. However, because the situation in the boundary layer is extremely complex, this method may also incorrectly estimate the CBL height for different reasons.
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