Impact of NOx and NH3 Emission Reduction on Particulate Matter across Po Valley: A LIFE-IP-PREPAIR Study

Air quality in Europe continues to remain poor in many areas, with regulation limits often exceeded by many countries. The EU Life-IP PREPAIR Project, involving administrations and environmental protection agencies of eight regions and three municipalities in Northern Italy and Slovenia, was designed to support the implementation of the regional air quality plans in the Po Valley, one of the most critical areas in Europe in terms of pollution levels. In this study, four air quality modelling systems, based on three chemical transport models (CHIMERE, FARM and CAMx) were applied over the Po Valley to assess the sensitivity of PM2.5 concentrations to NOx and NH3 emission reductions. These two precursors were reduced (individually and simultaneously) from 25% up to 75% for a total of 10 scenarios, aimed at identifying the most efficient emission reduction strategies and to assess the non-linear response of PM2.5 concentrations to precursor changes. The multi-model analysis shows that reductions across multiple emission sectors are necessary to achieve optimal results. In addition, the analysis of non-linearities revealed that during the cold season, the efficiency of PM2.5 abatement tends to increase by increasing the emission reductions, while during summertime, the same efficiency remains almost constant, or slightly decreases towards higher reduction strengths. Since the concentrations of PM2.5 are greater in winter than in summer, it is reasonable to infer that significant emission reductions should be planned to maximise reduction effectiveness

Direct and total irradiance: measurement, calculation and comparison with Lowtran 6 and Lowtran 7 predictions

The Lowtran code is used to determine solar transmission, direct solar irradiance and total radiance. In this paper results of comparisons between Lowtran 6 and Lowtran 7, the second including multiple scattering, are presented. These simulations are also compared with measurements of global irradiance carried out with a radiometer UV, in the range (295 divided-by 385) nm

Confronto tra previsioni di modelli numerici operazionali: caso dell'alluvione in Piemonte 4-6 Novembre 1994

La previsione fornita da due diversi modelli numerici (il modello Eta versione 1993 ed il modello tedesco del Deutscher Wetterdienst) viene confrontata per la situazione che ha portato alla disastrosa alluvione in Piemonte del novembre 1994, sia dal punto di vista degli usuali campi meteorologici che dei campi di precipitazione accumulata in periodi di 12 ore. Per questi ultimi sono riportati anche confronti con dati osservativi. Questo studio preliminare mostra come il modello Eta riproduca in modo complessivamente buono le caratteristiche salienti del flusso atmosferico, così come la struttura e l'evoluzione del campo di precipitazione

The Vaison-La-Romaine Intense Precipitation Event: Mesoscale Simulations

Some intense precipitation events are currently object of intensive study by means of numerical simulations in the framework of MAP (Mesoscale Alpine Program) Project. Among the others, the so called Vaison case, which occurred on September 22nd, 1992 has been selected for this work and the associated meteorological situation has been simulated using the Eta model. The flash flood associated with the intense precipitation resulted in serious damages, so that the correct meteorological forecast turns out to be of fundamental importance in order to try to reduce the dramatic impact of such episodes. This case seems to be a prototype intense rainfall event for the fall season in the Alpine Region. Nevertheless, several different numerical models are giving only partially successful representation of the episode, both in terms of the correct location and amplitude of the observed rainfall and of the actual chronology of the precipitation. The presence of a large amount of rain of convective origin due to the combination of several mesoscale convective systems in advance of a cold front crossing the French region during September 22nd seems to be one of the crucial aspects related to this failure. In this work, the results of Eta model simulations are presented, with a particular reference to the influence of initial conditions on the location of precipitation nuclei and to the simulated temperature and humidity fields with respect to the available observations and the ECMWF analysis

Simulation of Antarctic Surface Wind Using the Eta Model

In recent years numerical studies of Antarctic atmosphere have been performed using three-dimensional (3-D) mesoscale models. Katabatic winds and low surface temperatures are perhaps the most remarkable features of the Antarctic climate: the the annual mean wind speed reachs 19 m/s along the Adelie Coast (East Antarctica). A simulation using the limited area model ETA, with a horizontal grid resolution of 40 km and 38 levels in vertical, nested within the European Centre for Medium-Range Weather Forecasts (ECMWF) analyses is shown. The simulation of the period from 00 UTC January 16 to 00 UTC January 19 1994 captures many synoptic features seen in ECMWF analyses. Realistic confluence zones over the continent are evident in the wind at the lowest levels and, as expected , the wind speeds are high along the steep escarpment. Comparisons between simulated wind and AWS data at Adelie Land and Dome C will be presented

Numerical simulations of intense precipitation events using the Eta model.

In the framework of the international MAP project (Mesoscale Alpine Program) some events of intense precipitation were selectec and were object of intensive study, also using numerical models, in order to understand in details the features of the related atmospheric flow. Therefore, simulations of some of these episodes using a mesoscale operational model were performed and the results shown, with particular attention to the quantitative precipitation prediction. The used model is the Eta model, version 1993, and comparisons with ECMWF data and with observations were also shown

Operational Forecast and Daily Assessment of the Air Quality in Italy: A Copernicus-CAMS Downstream Service

In this paper, an operational forecasting and daily assessment system of air quality is presented. This new system is thought of as a Copernicus-CAMS downstream national service, able to develop and implement a service for air quality forecasting and monitoring in the Italian domain, running every day on the National territory. The system is being developed on behalf of a cooperation between Agenzia Spaziale Italiana (ASI) and Sistema Nazionale Protezione Ambiente (SNPA). SNPA is the network between Istituto Superiore per la Protezione e Ricerca Ambientale (ISPRA) and the Regional Environmental Agencies (ARPAs). The objective of the cooperation is to provide full operation service in terms of continuity, sustainability, and availability of the air quality forecast and evaluation services at the national level. The system forecasts and analyzes air quality throughout Italy, with a focus on Italian regions, for the principal pollutants: Particulate matter with diameter smaller than 10 μm (PM10), ozone (O3), and nitrogen dioxide (NO2). It includes a Chemical Transport Model (CTM) nested with the Copernicus Atmosphere Monitoring Service (CAMS) global model and data from the air quality monitoring stations in Italy. The system, under public control and based on open software, is now under testing. To date, it is able to deliver free open data, which is available to environmental agencies and citizens. The data are delivered both as maps and graphs, and as numerical data, useful for providing boundary conditions to local–high resolution-air quality models or for developing customized services. In this work, a downscaling application to a regional nested domain highlights how the new air quality forecasting system gains better results than the Copernicus-CAMS system

Some relevant aspects of the atmospheric flow in the period 3-6 November 1994

The event of intense precipitation causing flood and heavy damages over Piedmont in November 1994 has been simulated by means of the hydrostatic limited area model, the Eta model version 1993, at an horizontal resolution of about 25 km and 17 levels in the vertical.We analyse total and convective precipitation fields cumulated over a 6 hour period obtained from the Eta model, in order to select some areas and time intervals, in which the convective component of precipitation is prevailing. We analyse the behaviour of the convective adjustament process by comparing vertical cross sections and profiles obtained from Eta model against those obtained from ECMWF initialised analysis