Development and Evaluation of a JEDI-based Prototype Global Data Assimilation System at NCEP

Currently, the Global Data Assimilation System (GDAS) at the National Centers for Environmental Prediction (NCEP) uses the Gridpoint Statistical Interpolation (GSI) software for computing operational analyses. As part of the transition to the Unified Forecast System (UFS), GSI is slated to be replaced by a Unified Data Assimilation (UDA) framework based on the Joint Effort for Data assimilation Integration (JEDI). Led by the Joint Center for Satellite Data Assimilation (JCSDA), groups from NOAA, NASA, the US Navy and Air Force, and the UK MetOffice all contribute to development and testing of JEDI software. Efforts are underway at NCEP on replacing all GSI-based assimilation components with JEDI-based components for a future implementation of the GDAS. Here we present an overview of initial results from a low-resolution prototype JEDI-based atmosphere-only cycled GDAS. Technical developments and challenges including workflow and observation processing as well as scientific validation of system components are discussed. Concurrent with the transition to new software infrastructure, NCEP is also developing capabilities for coupled Earth system modeling and data assimilation (atmosphere, ocean, sea-ice, land, and composition), with the hope that UFS and JEDI will accelerate scientific innovations on this front. A brief summary of progress and plans for coupled Earth system DA in GDAS is also presented.