A 7-km Non-Hydrostatic Global Mesoscale Simulation for OSSEs with the Goddard Earth Observing System model (GEOS-5)

Using the Goddard Earth Observing System model (GEOS-5) the Global Modeling and Assimilation Office (GMAO) at NASA Goddard Space Flight Center has produced a 2-year non-hydrostatic global mesoscale simulation for the period 2005-2007. This 7-km GEOS-5 Nature Run (7km-G5NR) product will provide synthetic observations for observing system simulation experiments (OSSE)s at NASA, NOAA and other interested organizations.

By incorporating a non-hydrostatic finite-volume dynamical core with scale aware physics parameterizations, the 7km-G5NR produces organized convective systems and robust weather systems ideal for producing observations for existing and new remote sensing instruments. In addition to standard meteorological parameters, the 7km-G5NR includes 15 aerosol tracers (dust, seasalt, sulfate, black and organic carbon), O3, CO and CO2. This model simulation is driven by prescribed sea-surface temperatures and sea-ice, daily volcanic and biomass burning emissions, as well as high-resolution inventories of anthropogenic sources.

Highlights of the 7km-G5NR will be presented focusing on the representation of clouds and organized convection including tropical cyclones, mesoscale convective complexes, and mid-latitude cyclones; regional impacts of extreme events including atmospheric rivers and winter storms; and the potential for aerosol retrievals for OSSEs in cloudy regions. The fidelity of physical processes represented in the 7km-G5NR will be analyzed against observational data including eye-wall structure and reformation in intense tropical cyclones, towering cumulus convection within mesoscale convective complexes, and thunderstorm activity along frontal boundaries.

The 7km-G5NR has been produced focused clearly on application within the OSSE community. This focus includes global output of all 3-dimensional and surface data at 30-minute intervals throughout the 2-year period. Data access has been designed to allow multiple avenues for analysis including remote access via OpenDAP, and download tools for sub-setting in space and time.

Follow-on activities to this 7km-G5NR will be previewed including global cloud-resolving simulations at 3.5-km with an updated two-moment microphysics scheme, and improved vertical resolution for month-long segments initialized from the 7km-G5NR.