星载双频风场雷达热带气旋降雨区测风模拟  

Wind Retrieval Simulation in Tropical Cyclone for FY-3 Dual-Frequency WFR

作　　者：窦芳丽[1] 卢乃锰[2] 谷松岩[2] 

机构地区：[1]中国气象科学研究院,北京100081 [2]中国气象局中国遥感卫星辐射测量和定标重点开放实验室、国家卫星气象中心,北京100081

出　　处：《应用气象学报》2012年第4期467-477,共11页Journal of Applied Meteorological Science

基　　金：国家863计划项目“星载毫米/亚毫米波云雨大气遥感的仿真数值模拟研究”(2007AA12Z115)

摘　　要：基于大气辐射传输理论分别建立Ku波段和C波段的降雨模型,模拟热带气旋降雨区洋面的雷达回波并反演了洋面10 m风场,用于研究降雨对测风的影响以及风云三号双频风场雷达(WFR)的测风能力。分析表明:回波的衰减或增强取决于降雨衰减项和后向散射项的相对大小;热带气旋的降雨使反演风速偏小,风向精度降低,Ku波段相对于C波段更易受影响,在高风速(超过30 m·s^(-1))条件下,可达5～20 m·s^(-1)的负风速偏差。反演结果表明:双频反演的新方法能够结合Ku波段与C波段的优势,双频最大似然估计(MLE)方法在分辨率上优于C波段单频反演,相对Ku单频反演能降低降雨对测风的衰减作用,结合双频MLE方法和C波段单频反演优势的分区反演方法可以显著减小降雨偏差,提高风速反演精度,在有风云三号湿度计同步观测的条件下,是提高热带气旋降雨区测风精度的有效手段。Tropical cyclone is one of the primary disastrous synoptic systems in China. With the continuous observation, global coverage and the ability to penetrate through precipitation layer, microwave sensors on polar orbit satellites can provide more precise observations of the tropical cyclone location and intensity for marine extreme weather forecasting, which will compensate for the shortage of conventional observations. The FY-3 satellite microwave scatterometer, named Wind Field Radar （WFR）, is the only way to measure ocean vector winds （OVW）. Compared with single-frequency scatterometer, dual-frequency scatterometer has advantages in higher spatial resolution and better response to winds in extreme weather conditions, where high winds are usually associated with high rain rates. The Jet Propulsion Laboratory （JPL） has developed a conceptual design for a Dual Frequency Scatterometer （DFS） in the Extended Ocean Vector Winds Mission put forward in 2007. The concept of Rotating Fan Beam Scatterometer which will be extended to dual-frequency mode has been studied under ESA. The WFR installed on FY-3 satellite which will be launched in 2016 is designed to use the dual-frequency and dual-polarization time-sharing observation pattern. Rain perturbations result from volume scattering and attenuation by precipitation in the atmosphere, as well as changes of sea surface roughness by impinging rain drops. Few studies which investigate effects of rain on Ku-band and C-band scatterometer data indicate that the impact of rain to sea surface is a complex phenomenon not yet fully understood, and it＇s not dominating in high wind and strong rain fall areas. Therefore, changes in surface roughness are not considered here. The purpose of this study is to investigate the potential of the WFR proposed to fly aboard FY-3 satellite to measure OVW in rain fall areas of Typhoon Ivan. A theoretical model based on radiation transfer equation including rain attenuation and scattering, has been developed to quantify the

关 键 词：降雨模型 风场 微波散射计 辐射传输 

分 类 号：P412.16[天文地球—大气科学及气象学]