GEOS-5 Data Assimilation System Updates Andrea Molod GMAO Staff

GEOS FP system major upgrade on January 24, 2017: e5131fp  f516fp Transition from Hybrid 3D-Var to Hybrid 4D En-Var assimilation system Doubled horizontal resolution from ~25 km to ~12.5-km Re-tuning of many aspects of moist physics Aerosol module (GOCART) now includes nitrates Led to improvements in forecast skill score Note: present GEOS FP file specification is unchanged from previous system. Upcoming system changes will include output on the cubed sphere grid at a horizontal resolution to be determined.

Improvements in forecast skill score RMS Error RMS Error Anomaly Corr f516 e5131 Anomaly Corr Anomaly Corr Anomaly Corr

Transition from Hybrid 3D-Var to Hybrid 4D En-Var Surface U analysis increment: Single obs case 3DVar Hybrid 3D-Var Hybrid 4D-EnVar -3h 0h +3h -3h 0h +3h -3h 0h +3h Courtesy of: Amal El Akkraoui

Re-tuning of many aspects of moist physics Diff Conv Mass Flux Conv Mass Flux at 800 mb

Re-tuning of many aspects of moist physics Diff Cloud Fraction Cloud Ice Content

Re-tuning of many aspects of moist physics Short-Wave Diabatic Heating Diff Short-Wave Diabatic Heating Specific Humidity

Implications of change in moist physics Diff V-wind PBL Height

Re-tuning of many aspects of moist physics Cloud Top Pressure

GEOS-5 Systems WIKI page - General user information and links: geos5.org GMAO at IGC8: Steven Pawson (steven.pawson@nasa.gov) - Head of Office Andrea Molod (andrea.molod@nasa.gov) Clara Orbe (clara.orbe@nasa.gov) Christoph Keller (christoph.a.keller@nasa.gov)