吴举秀,窦芳丽,安大伟,顾瑜. 2019. 94\220 GHz星载雷达双波长比对非球形冰晶云参数敏感性分析[J]. 气象学报, (0):-, doi:10.11676/qxxb2019.016
94\220 GHz星载雷达双波长比对非球形冰晶云参数敏感性分析
Sensitivity of dual wavelength reflectivity ratio of 94\220 GHz space-borne radars to the cloud parameters with non-spherical ice crystals
投稿时间:2018-02-11  修订日期:2018-04-13
DOI:10.11676/qxxb2019.016
中文关键词:  非球形冰晶  星载94\220 GHz 云雷达  双波长比  冰晶谱参数
英文关键词:non-spherical ice particles, 94\220 GHz space-borne cloud radars, dual wavelength reflectivity ratio, parameters of ice particles size distribution
基金项目:国防科工局“十二五”项目“太赫兹测云成像技术研究”,科技部公益性行业专项(GYHY201406033);国家自然科学基金 (41305031);江苏高校优势学科建设工程资助项目(PAPD);
作者单位E-mail
吴举秀 山东省气象局大探中心 gurunmin@163.com 
窦芳丽 中国气象局国家卫星气象中心 8243859@qq.com 
安大伟 中国气象局国家卫星气象中心 andawei@cma.gov.cn 
顾瑜 青岛市气象局 1021219117@qq.com 
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中文摘要:
      利用不同形状冰晶的散射特性,获得了非球形冰晶云的94\220 GHz测云雷达双波长比DWR(dual wavelength reflectivity ratio),探讨了非球形冰晶云的DWR与云内微物理参数的关系,分析了衰减前后的星载雷达反射率因子及DWR的垂直廓线。结果表明:(1)DWR可以反映小到0.1 mm中值尺度的冰粒子,对粒子总数、谱的形状参数不敏感,对粒子大小、形状、云衰减较敏感。(2)雷达灵敏度一定时,星载雷达可测云厚和雷达波长、IWC的垂直分布、云厚及衰减有关;没有进行衰减订正时,DWR和衰减有关,冰水含量(ice water content ,IWC)越大、波长越短,衰减越大,DWR最大值和可探测云厚有关。两部雷达可探测IWC为0.001-0.1 g/m3、厚2 km的冰云;当云厚5 km、IWC垂直分布在0.001-0.2 g/m3时,云厚的94%基本可以被220 GHz云雷达探测到。(3)如果两部雷达气象方程中用水的介电因子,测量回波强度应进行介电因子的订正后再计算DWR。
英文摘要:
      The dual wavelength reflectivity ratio (DWR) of 94\220 GHz radar to non-spherical ice clouds were obtained based on the scattering characteristics of ice crystals with different shapes, and the relationships between the DWR and the cloud parameters were analyzed, then the vertical profiles of the radar reflectivity factors and DWR both before and after attenuation were studied. The results are as follows: (1) The DWR are sensitive to the particles size and shape, the attenuation from clouds and the median maximum dimension of the particles size distribution (PSD) even to 0.1mm, but insensitive to the particle concentration and shape parameters of the PSD. (2) When the sensitivity of radar receiver is certain, the thickness of cloud detected by space-borne radars depends on the wavelengths of radars, the vertical profiles of the ice water content(IWC), the thickness of the cloud and the attenuation. In the condition of no attenuation correction, the DWR relate to the attenuation and the maximum are decided by the detected cloud thickness , while the more IWC and shorter wavelength are, the larger attenuation is. As a result, the two radars can detect the ice clouds with IWC =0.001~0.1 g/m3 and thickness in 2 km, furthermore, 94% thickness can be explored if the ice clouds with IWC =0.001~0.2 g/m3 and thickness in 5 km. (3) when the dielectric factors of water are using in the two radars’ meteorological equations, it is necessary that the DWR are obtained after directly detected echo intensity are corrected.
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