Recent Results in the Validation and Monitoring of COSMIC Radio Occultation Performance

Since the launch of the six COSMIC satellites in 2006, the Radio Occultation (RO) data have been playing an increasing role in numerical weather forecast. The bending angles derived from the GPS carrier phase from RO measurements have been directly assimilated into NWP models, and serve as anchors for assimilating other satellite data. Given the significant roles of RO, it is important to monitor the performance of the COSMIC RO at different levels of data to ensure the data quality. To this end, NOAA has developed integrated calibration, verification, and validation system to ensure data quality.

This paper focuses on the analysis of the latest COSMIC performance trends, and comparisons with other measurements such as those from microwave. Our study shows that among the six COSMIC satellites, only two of them are producing data currently (FM1 and FM6). However, FM1 is not stable and often leads to data gaps. There is also a decrease in the number of good profiles that reach the low troposphere such as 850hPa, which may lead to erroneous trends in comparisons with microwave measurements if not handled correctly. Our goal is to enhance the monitoring and validation capabilities in preparation for the launch of the COSMIC 2 in 2018.