T. Paccagnella

Operational meteorological pre-processing at Emilia-Romagna ARPA Meteorological Service as a part of a decision support system for air quality management

In the framework of the Integrated Decision Support System for air quality assessment and management operating at the Emilia-Romagna Region Meteorological Service, an appropriate meteorological input is necessary: 1) to provide meteorological information for evaluation of the pollution data observed at the urban monitoring stations; 2) as input data to run daily statistical models for air quality forecasts; 3) as input to run deterministic dispersion models. Thus, a meteorological pre-processor has been implemented operationally. The runs are made on a daily basis in a diagnostic configuration in the whole Po valley basin and for forecasting on selected grid points near the main urban areas of the Emilia-Romagna region.

High-resolution numerical modelling of convective precipitation over Northern Italy

SummaryA number of forecast experiments were performed in order to assess the capability of reproducing, by means of a limited-area numerical model, the highly structured mesoscale circulations occurring in the Po Valley of Northern Italy during a north-westerly cold front passage across the Alpine chain, with particular attention to the modelling of the effects of organized convection. The case-study occurred during summer 1987 and the model used throughout was the 1989 version of the UB/NMC Limited Area Model (University of Belgrade, National Meteorological Centre of Washington). The model was integrated both with eta, η, and sigma, ϑ, as vertical coordinates and ECMWF initialized analyses were always used as initial conditions. ECMWF initialized analysis or operational forecast fields were also used for updating in time the lateral boundary conditions. Experiments show qualitative and quantitative agreement with observations, both in upper-air geopotential height fields, in MSLP and in cumulated precipitation. Several modelling issues were also investigated, e.g. sensitivity of the results to horizontal and vertical model resolution and to the influence of the lateral boundaries poitioning, finding large effects of the latter on quantitative precipitation fields. Difficulties in modelling very localized mesoscale phenomena, e.g. organized convective thunderstorms in the Po Valley and Alpine North Foehn in the Milan area, were generally encounted.

Analysis of meteorological parameters relating to Adriatic eutrophication

In this paper Adriatic eutrophication is examined with respect to its relationships with meteorological parameters. As regards the eutrophication index, the concentration of chlorophyll a has been taken from measurements performed by the ship «Daphne» (of Emilia Romagna Region) on the Adriatic coast from Porto Garibaldi to Cattolica, 500 m offshore, during the period 1985-1988. For the same period, meteorological data have been examined in respect of mean daily temperature, precipitation, and sea level pressure observed in some synoptic weather stations of the central and south-east Po Valley.

Calibration of Limited-Area Ensemble Precipitation Forecasts for Hydrological Predictions

AbstractThe main objective of this study is to investigate the impact of calibration for limited-area ensemble precipitation forecasts, to be used for driving discharge predictions up to 5 days in advance. A reforecast dataset, which spans 30 years, based on the Consortium for Small Scale Modeling Limited-Area Ensemble Prediction System (COSMO-LEPS) was used for testing the calibration strategy. Three calibration techniques were applied: quantile-to-quantile mapping, linear regression, and analogs. The performance of these methodologies was evaluated in terms of statistical scores for the precipitation forecasts operationally provided by COSMO-LEPS in the years 2003–07 over Germany, Switzerland, and the Emilia-Romagna region (northern Italy). The calibration provided a beneficial impact for the ensemble forecast over Switzerland and Germany; whereas, it resulted as less effective for Emilia-Romagna. The analog-based method seemed to be preferred because of its capability of correct position errors and spr...

FROST-2014: The Sochi Winter Olympics International Project

CapsuleSix nowcasting systems, nine deterministic mesoscale numerical weather prediction models, and six ensemble prediction systems took part in the FROST-2014 project.

Data assimilation of radar reflectivity volumes in a LETKF scheme

Quantitative precipitation forecast (QPF) is still a challenge for numerical weather prediction (NWP), despite the continuous improvement of models and data assimilation systems. In this regard, the assimilation of radar reflectivity volumes should be beneficial, since the accuracy of analysis is the element that most affects short-term QPFs. Up to now, few attempts have been made to assimilate these observations in an operational set-up, due to the large amount of computational resources needed and due to several open issues, like the rise of imbalances in the analyses and the estimation of the observational error. In this work, we evaluate the impact of the assimilation of radar reflectivity volumes employing a local ensemble transform Kalman filter (LETKF), implemented for the convection-permitting model of the COnsortium for Small-scale MOdelling (COSMO). A 4-day test case on February 2017 is considered and the verification of QPFs is performed using the fractions skill score (FSS) and the SAL technique, an object-based method which allows one to decompose the error in precipitation fields in terms of structure (S), amplitude (A) and location (L). Results obtained assimilating both conventional data and radar reflectivity volumes are compared to those of the operational system of the Hydro-Meteo-Climate Service of the EmiliaRomagna Region (Arpae-SIMC), in which only conventional observations are employed and latent heat nudging (LHN) is applied using surface rainfall intensity (SRI) estimated from the Italian radar network data. The impact of assimilating reflectivity volumes using LETKF in combination or not with LHN is assessed. Furthermore, some sensitivity tests are performed to evaluate the effects of the length of the assimilation window and of the reflectivity observational error (roe). Moreover, balance issues are assessed in terms of kinetic energy spectra and providing some examples of how these affect prognostic fields. Results show that the assimilation of reflectivity volumes has a positive impact on QPF accuracy in the first few hours of forecast, both when it is combined with LHN or not. The improvement is further slightly enhanced when only observations collected close to the analysis time are assimilated, while the shortening of cycle length worsens QPF accuracy. Finally, the employment of too small a value of roe introduces imbalances into the analyses, resulting in a severe degradation of forecast accuracy, especially when very short assimilation cycles are used.

Porting a Limited Area Numerical Weather Forecasting Model on a Scalable Shared Memory Parallel Computer

As new parallel machines become popular commercially, it is important to understand if they are adequate for performing and scaling well for a range of applications. This paper describes the porting of a weather forecast limited area model from a vector machine to a recent SMP-multiprocessors and evaluates the performances obtained.