FY-3C无线电掩星折射率廓线的反演及验证

Retrieval and Validation of FY-3C Radio Occultation Refractivities

  • 摘要: 2013年, 中国发射了首颗进行全球导航卫星系统(global navigation satellite system,GNSS)无线电掩星观测的气象卫星FY-3C,其掩星数据产品已由国家卫星气象中心(national satellite meteorological center,NSMC)发布。基于FY-3C附加相位数据,通过几何光学反演和全谱反演相结合的方法自主反演获取大气折射率廓线,并利用NSMC提供的折射率产品和欧洲中期天气预报中心(European Centre for Medium-Range Weather Forecasts, ECMWF)的气候再分析数据集(ECMWF reanalysis-interim, ERA-Interim)对反演结果进行验证。2017年全年FY-3C掩星折射率自主反演的成功率为82%,与NSMC 83.5%的反演成功率基本一致。以ERA-Interim再分析资料为参考,自主反演折射率相对偏差绝对值在25 km以下, 小于1.5%,略优于NSMC产品,但偏差标准差比NSMC产品略大,达到了3.6%。自主反演和NSMC的折射率廓线在高纬地区的相对偏差均低于中低纬地区,且自主反演折射率的相对偏差总体上在夏季高于冬季。

     

    Abstract:
      Objectives  In 2013, the first meteorological satellite of China with global navigation satellite system (GNSS) radio occultation (RO) observation capability, FY-3C, was launched, and FY-3C RO products have been released by the National Satellite Meteorological Center (NSMC).
      Methods  In the present study, the RO refractivity profiles are retrieved from FY-3C excess phase data during the whole year of 2017 by combing the geometric optical inversion and the full spectrum inversion (FSI) algorithms, and the quality of the retrieved refractivity profiles are evaluated with NSMC products and ERA-Interim reanalysis data.
      Results  The success rate of our retrieval process is 82%, which is basically consistent with that of NSMC's 83.5%. With ERA-Interim reanalysis data as references, the relative biases (RBs) of the inverted refractivities are smaller than 1.5% below 25 km, which are slightly better than those of the NSMC refractivity products. While the standard deviations of the relative biases (SDRBs) of the inverted refractivities reach 3.6%, which are larger than those of the NSMC refractivity products.
      Conclusions  Compared with ERA-Interim reanalysis data, the RBs and the SDRBs of the inverted refractivities and NSMC products are significantly lower at high latitudes than those at middle and low latitudes, and the RBs of the inverted refractivities are generally larger in summer than in winter.

     

/

返回文章
返回