摘要
利用94/220GHz双频云雷达的探测优势,结合短柱、三瓣子弹花和星状雪花三种非球形冰晶粒子的散射特性,对双频云雷达云微物理参数反演算法进行了研究。通过建立双频比和中值直径的关系,再通过后向迭代的双频反演算法计算出谱参数的最优解,进而反演云微物理参数并分析反演误差。最后,通过数值试验,对考虑系统噪声和随机噪声后的反演误差进行了比较分析,并提出了仪器信噪比的指标需求。结果表明:双频联合可以较好地反演非球形冰晶的云微物理参数,为了保证0.2 g/m^(3)以下冰水含量的反演误差小于30%,仪器的信噪比不能低于11.39dB,为国内开展星载云雷达指标设计和云微物理参数反演研究提供参考。
In order to meet the urgent requirement for China spaceborne cloud radar detection and accurate retrieval of cloud microphysical properties,integrating the detecting advantages of dual-frequency 94/220 GHz cloud radars,and combining scattering and attenuation properties of non-spherical ice particles,a dual-frequency retrieval algorithm of cloud microphysical parameters is proposed based on the non-spherical ice particles scattering database.By assuming the gamma particle size distribution of cloud ice and establishing relationships between dual frequency ratio and retrieval variable volume median diameter,three types have been chosen.Based on it,the optimal solutions of particle size dis‐tribution parameters are obtained after backward iteratively calculating,then the microphysical parameters of cloud could be retrieved based on particle size distribution,and the error can be calculated and analyzed.By adding system noise and random noise,the retrieval errors are compared with original data and the requirement of signal-to-noise ratio is proposed.As a result,the retrieval of non-spherical ice cloud microphysical parameters based on dual-frequency 94/220GHz and iterative backward retrieval algorithm is well consistent with simulated true data.What’s more,the signal to-noise ratio cannot be smaller than 11.39dB in order to get 30%retrieval error for ice water content under 0.2g/m^(3),which gives some references for domestic spaceborne cloud radar design and retrieval research of non-spherical ice cloud microphysical parameters.
作者
吴琼
仰美霖
尹红刚
商建
WU Qiong;YANG Mei-Lin;YIN Hong-Gang;SHANG Jian(National Satellite Meteorological Center,Beijing 100081,China;Institute of Urban Meteorology,China Meteorological Administration,Beijing 100089,China)
出处
《红外与毫米波学报》
SCIE
EI
CAS
CSCD
北大核心
2021年第5期605-615,共11页
Journal of Infrared and Millimeter Waves
基金
国家自然科学基金(41905063,61527805)
国防科工局十三五民用航天项目(XX云雨测量雷达)。
关键词
双频反演
云雷达
粒子谱参数
非球形冰晶
dual-frequency retrieval
cloud radar
particle size distribution
non-spherical ice particles
