Data assimilation for the Model for Prediction Across Scales – Atmosphere with the Joint Effort for Data assimilation Integration (JEDI-MPAS 1.0.0): EnVar implementation and evaluation

Abstract. On 24 September 2021, JEDI-MPAS 1.0.0, a new data assimilation (DA) system for the Model Prediction Across Scales – Atmosphere (MPAS-A) built on software framework of Joint Effort Data Integration (JEDI) was publicly released community use. Operating directly native MPAS unstructured mesh, capabilities include three-dimensional variational (3DVar) and ensemble–variational (EnVar) schemes as well ensemble DA (EDA) technique. observation side, one advanced feature in is full all-sky approach satellite radiance with introduction hydrometeor analysis variables. This paper describes formulation implementation EnVar JEDI-MPAS. 1.0.0 evaluated month-long cycling 3DEnVar experiments global 30–60 km dual-resolution configuration. The robustness credible performance are demonstrated by establishing benchmark non-radiance experiment, then incrementally adding microwave radiances from three sources: Advanced Microwave Sounding Unit-A (AMSU-A) temperature sounding channels clear-sky scenes, AMSU-A window Humidity Sounder (MHS) water vapor scenes. behaves substantial significant positive impact obtained almost all aspects forecast verification when progressively more data. In particular, day 5 best-performing experiment yields an anomaly correlation coefficient (ACC) 0.8 500 hPa geopotential height, gap roughly half compared to cold-start forecasts initialized operational analyses National Centers Environmental Prediction, whose ACC does not drop until lead time 5.5 d. indicates JEDI-MPAS's great potential both research operations.