FY-3C的掩星探测特点和初步结果

Status of Radio Occultation Sounding Technology of FY-3C GNOS

全球导航卫星掩星接收机（GNOS-Global Navigation Satellite System Occultation Sounder）是风云卫星首次尝试掩星探测技术的仪器,它能够同时兼容GPS（Global Positioning System）和我国自主研制的北斗BDS（Bei Dou navigation satellite）信号。简要介绍了国际上掩星探测技术的发展情况,以及我国的首个民用掩星接收机GNOS的仪器概况,对其数据的主要处理过程进行了描述,并利用欧洲中期天气预报中心（ECMWF）再分析资料进行对比分析,结果显示GNOS-GPS掩星中性大气折射率在5～25km有最优的探测精度,标准偏差在1%以内,中高纬度的精度好于低纬度地区。掩星探测的精度与国外同类掩星数据类似,体现了GNOS掩星探测的价值,但对于30km以上的高度,精度还有待进一步提高。

This paper gives a brief introduction to the status of radio occultation technology implemented on FY-3C and describes the instrument mounted on it,GNOS（Global Navigation satellite system Occultation Sounder）.The data processes are stated as well.To evaluate its performance,the refractivity profiles are compared by makking use of ECMWF reanalysis in terms of global and different latitudes.The results show that the performance of GNOS-GPS is the best at the vertical range of 5-25 km with the standard deviation below 1%,consistent with other occultation sounders.The expected result demonstrates that middle and high latitudes show less bias than lower areas,due to fewer multipath effects of moist atmosphere.These results illustrate that FY-3C has possessed a new sounding ability with the first trial,but still has much work to do to improve the precision at higher altitude.