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Kucharski F.,Abdus Salam International Center For Theoretical Physics | Molteni F.,European Center for Medium Range Weather Forecasts | King M.P.,University of Bergen | Farneti R.,Abdus Salam International Center For Theoretical Physics | And 2 more authors.
Bulletin of the American Meteorological Society | Year: 2013

The use of idealized climate models in the search for physical understanding of the behavior of complex general circulation models (GCM) has been advocated by several experts. There are many intermediate complexity models, which have been developed into Earth system models of intermediate complexity (EMICs). A number of these models are participating in the IPCC Fifth Assessment Report. Experts have re-emphasized the importance of intermediate complexity modeling and suggested that results from such a model were useful in the understanding of climate variability and change. The role of intermediate role of intermediate has also been important as a tool for researchers with less than optimal resources. Another important area where intermediate complexity models are widely used is in the work of graduate students who gain better scientific and software insights permitted by a simpler model. Source

Manzato A.,OSMER Osservatorio Meteorologico Regionale dellARPA Friuli Venezia Giulia | Davolio S.,CNR Institute of atmospheric Sciences and Climate | Miglietta M.M.,CNR Institute of atmospheric Sciences and Climate | Pucillo A.,OSMER Osservatorio Meteorologico Regionale dellARPA Friuli Venezia Giulia | Setvak M.,Czech Hydrometeorological Institute
Atmospheric Research | Year: 2015

On 12 September 2012 a sequence of convective events hit the northeastern part of Italy and in particular the eastern part of Veneto and the plain of Friuli Venezia Giulia regions. During the day at least two events could be classified as supercells, the first one being also associated with a heavy hailfall. After a few hours, a third storm system, resembling a squall-line, although of limited dimensions, swept over the area.This event occurred during the first Special Observing Period (SOP1) of the HyMeX project as IOP2 (Intense Observing Period) and - also for this reason - many observations managed by different institutions were collected, including Doppler radar, extra-soundings, sodar and surface stations. Moreover, EUMETSAT was conducting its first experimental 2.5-minute rapid scan with the MSG-3 satellite, with data available from early morning until 0900 UTC of the IOP2 day.Several mesoscale models were run during the HyMeX SOP to support the field operations. A comparison between simulations of two high-resolution models (MOLOCH and WRF) is presented here and shows the capability in forecasting the intense convective activity in the area, although the exact temporal evolution of the systems was missed. Model simulations also provide useful insights concerning the mesoscale conditions conducive to the development of the convective systems.Finally, a diagnostic tool (Corfidi and Bunkers vectors) is applied using the model wind field, in order to infer further information on the temporal evolution of the convective cells. © 2014 Elsevier B.V. Source

Manzato A.,OSMER Osservatorio Meteorologico Regionale dellARPA Friuli Venezia Giulia | Cicogna A.,OSMER Osservatorio Meteorologico Regionale dellARPA Friuli Venezia Giulia | Pucillo A.,OSMER Osservatorio Meteorologico Regionale dellARPA Friuli Venezia Giulia
Atmospheric Research | Year: 2015

Friuli Venezia Giulia (FVG) is a region in Italy with very complex orography, having an annual rainfall amount that varies from about 900. mm on the coast to more than 3200. mm in the Julian Prealps. A network of 104 raingauges placed around the FVG territory was used to extract the absolute maximum rain accumulated every 6. h, during the period 16 February 2006 to 15 February 2015 (9. years). Interannual, annual, weekly and daily cycles of three classes of rain intensities are analyzed, finding that significant rainfalls (MaxRain. > 5. mm) are more frequent in the May to mid-August period, while the heaviest rainfalls (> 40. mm) are more probable between May and the beginning of December, with a peak at the very beginning of November.ECMWF 6-h forecasts at 18 gridpoints (spaced at 0.25°) above the FVG region are studied for the same period, to find the maximum 6-h rain forecasted by the ECMWF model from +. 6 to +. 48. h and correlate it with the observed maximum rain of all the 104 raingauges. It is found that the correlation coefficient R is higher at 0000-0600 UTC and minimum at 1800-0000 UTC, while the BIAS is always negative (underestimation), varying between -3.5 and -6.9. mm. Looking at more homogeneous subareas, ECMWF has a much worse BIAS and RMSE for the Prealps zone, while its correlation coefficient is lower for the coastal and plains zones.For comparison, a similar exercise is repeated using a LAM model (ALADIN-ARSO), finding better BIAS and RMSE, but a lower skill for the mean correlation coefficient. Hence, a linear statistical method (multiregression with exhaustive input selection) for forecasting the maximum 6-h rain using as candidate predictors the direct model output (absolute values, anomalies, standardized values, plus mean, max and SD in time and space) is developed independently for four different sub-regions and two periods of the year starting from the ECMWF forecast. It is found that the strong BIAS in the Prealpine area can easily be removed, substantially improving the forecast, in particular during the October-April period, while the plains and coastal area, in particular during May-September, have the lowest predictability. © 2015 Elsevier B.V. Source

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