GNSSRO Data Assimilation Development Activities at JCSDA

The JCSDA supports its partner agencies in the effort to assimilate Radio-Occultation (RO) observation from Global Navigation Satellite Systems (GNSS). The objectives are twofold:

1. Adding into operations, observations from new platforms as they become available, and
2. Developing and transitioning advanced assimilation capabilities.

Efforts toward 1) over the past year have focused on the Korean satellite KOMPSAT-5. Code modifications needed to assimilate bending angle data from the KOMPSAT-5 satellite were submitted, reviewed and approved by the GSI Review Committee and committed to the GSI code repository. EMC incorporated the KOMPSAT-5 code changes into its FV3-beta code suite. The KOMPSAT-5 software is considered for the Spring 2019 operational implementation and is going through the pre-implementation parallel testing. JCSDA is now looking at possible operations with RO data from the ROSA GPS receiver on board the Megha-Tropique satellite. More on those activities are presented in a separate talk at the Ninth Conference on Transition of Research to Operations.

This talk focuses on 2) and reports on JCSDA recent activities to port GSI RO forward operators into the Joint Effort for Data assimilation Integration (JEDI) framework, as well as the development of new 2-Dimensional forward operators. This work is conducted in preparation of the coming COSMIC-2 mission which, together with the NOAA Commercial Weather Data Enterprise program, will bring in 2019 an unprecedented number of radio-occultation observations. Existing local 1-Dimensional RO forward operators, like the one currently in use for operations in the GSI, may not be able to take full advantage of certain features of those new missions, in particular COSMIC-2 deep penetration capability, because of their inability to account for horizontal gradients. JCSDA Partners including the US Navy, NOAA (OAR/ AOML an NESIDS/STAR0 have been working with the University of Maryland and ECMWF to implement 2D forward operators into JEDI, and has began to conduct inter-comparison experiments in order to evaluate their benefits.