The Meteorological Global Model GLOBO at the ISAC-CNR of Italy Assessment of 1.5 Yr of Experimental Use for Medium-Range Weather Forecasts

Since August 2009, the GLOBO atmospheric general circulation model has been running experimentally at the Institute of Atmospheric Sciences and Climate (ISAC) of the National Council of Research of Italy. GLOBO is derived from the Bologna Limited Area Model (BOLAM), a gridpoint limited-area meteorological model that was developed at the same institute and that has been extended to the entire earth atmosphere. The main dynamical features and physical parameterizations of GLOBO are presented. Starting from initial conditions obtained from the analysis of the NCEP Global Forecast System (GFS) model valid at 0000 UTC, 6-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-yr period included the calculation of the monthly averaged root-mean-square errors (model prediction versus gridded analyses) of geopotential height at 500 hPa and mean sea level pressure for the northern and southern extratropics, performed accordingly to WMO Commission for Basic Systems (CBS) standards. The verification results are compared with models from other global data processing and forecasting system centers, as are 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.