The meteorological global model GLOBO at the ISAC-CNR of Italy: Assessment of 1.5 years of experimental use for medium range weather forecast

Since August 2009, the atmospheric general circulation model GLOBO has been running experimentally at the Institute ISAC of the National Council of Research of Italy. GLOBO is derived from the grid point limited area meteorological model BOLAM, developed at the same institute, extended to the entire earth atmosphere. Here, the main dynamical features and physical parameterizations of GLOBO are presented. Starting from initial conditions obtained from the analysis of the NCEP-GFS model valid at 00 UTC, six day forecasts with average horizontal resolution of 32 km were performed on a daily basis and in real time. The assessment of the forecast skill during the 1.5-year period included the calculation of the monthly averaged root-mean-square errors (model prediction vs. gridded analyses) of geopotential height at 500 hPa and mean sea level pressure for the Northern and Southern extra-tropics, performed accordingly to WMO/CBS standards. The verification results are compared with those of the global forecast models of the Global Data Processing and Forecasting System (GDPFS) centers, as available in the literature. The GLOBO skill for medium range forecasts turns out to be comparable to that of the above models. The lack of analyses based on model forecasts and data assimilation is likely to penalize the scores for shorter term forecasts.