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

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 5-25km 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.