1,721,035 research outputs found
Valutazione dell'impatto ambientale delle emissioni in atmosfera nel distretto di cairo Montenotte (SV) - relazione di consulenza tecnica: Procedimento Nr. 653/14 Procura della repubblica di Savona
No full textRisultati della campagna di monitoraggio gas e PM10 ed analisi di source apportionmen
Indagine ambientale per la rilevazione di inquinanti atmosferici mediante modelli a recettore del distretto monfalconese (Procedimento nr. 1213/13 R.N.R.I. Procura della Repubblica di Gorizia)
No full textRisultati di una campagna di monitoraggio di gas e particolato atmosferico nell'area di Monfalcone - Studio del profilo delle sorgenti di emissione del distrett
An outstanding Saharan dust event at Mt. Cimone (2165 m a.s.l., Italy) in March 2004
No full textDust outbreaks are very common throughout the year, with a peak frequency in spring (March, April, May) towards the Atlantic Ocean, or in late spring/summer (May, June, July) towards the Mediterranean Sea (even if winter and especially autumn events, though less frequent, are usually very intense). Every year strong winds blowing over the Sahara desert lift hundreds of millions of tons of dust high into the sky over North Africa.
In 2004, from 13 to 15 March, a severe PM episode was observed at Mt. Cimone. Figure 1, showing the trend of PM10, 210Pb, number of fine and coarse particles, for the year 2005, highlights a clear increase of all these parameters during the Saharan Dust episode. In particular, PM concentration exceeded 80 μg/SCM, a value seven times greater than the mean level during the preceding and subsequent days, and the maximum PM10 concentration recorded at Mt Cimone in more than 12 years observations. This episode has been ascribed to a long lasting Saharan dust outbreak, starting at the beginning of March, and first impacting the Atlantic Ocean and then the Mediterranean area.
This event originated from the Bodele depression in northern Chad, a remarkable as well as well recognized source of mineral dust, and the analysis of aerosol optical depth revealed that dustiness conditions occurred along the entire ITCZ. On 5th March 2004 images from the visible channel of the SeaWIFS satellite show a huge, dense, meridionally oriented dust plume off the northwestern African coast from west of Madeira to Cape Verde, sustained by hazy and prolonged Harmattan conditions. This plume spreads laterally, moves westward and formed an arc more than 5000 km long from Guinea to the northern tip of Morocco. The plume crossed the Atlantic Ocean and impacted onto the Caribbean region.
At the end of this extraordinary episode, the sequence of two main meteorological patterns: 1) the penetration of an upper-level trough to low latitudes with a minimum centered over the North-western Algerian coast; and 2) a Sahara high extending all over the Mediterranean Sea with an elongated north-eastward tongue, mobilized dust to the south of the northern Atlas Mountains in Morocco and western Algeria. The development of a steep gradient between a trough and a Saharan high along the Western Sahara and the western Mediterranean basin is a typical condition during which dust is rapidly transported toward the central Mediterranean.
The aerosol optical depth at the beginning of the second dust outbreak (on 13th March, 2004) and the average over the period 10-15 March 2004 clearly show the severe dust outbreaks across the Atlantic and the Northern part of Italy: during this event the monitoring site at Mt. Cimone has found along the main axis of the dust plume, and recorded a concentration as high as 80 μg/SCM. Detailed analysis of the event is discussed and presented
Modeling the transport of Saharan dust toward the Mediterranean region: an important issue for its ecological implications
No full textAirborne particulate matter (PM) is presently an environmental problem of primary concern, whose role in air quality, climatic and ecological issues is well recognized, though still a matter of extensive investigations (Intergovernmental Panel on Climate Change, 2007).It is of great scientific interest to detect sources of atmospheric particulate matter and quantify their influence on the global and local scales. Unfortunately, emissions are usually not directly available, while PM concentration time series are experimentally accessible, so that the problem often consists in "inverting" these data to determine the region of influence that caused the measured concentration. In this paper we are concerned with an alternative approach to inverse modeling based on backward trajectory analysis (BTA); this approach has the potential to overcome some limitations associated with traditional BTA.We apply this method to the analysis of PM time series from the Monte Cimone observatory, hereafter MCT, a high altitude station on the top of the Italian Northern Apennines, with the aim of estimate the contribution of Saharan dust transport on PM concentration levels registered in the Mediterranean region
Aerosol atmosferico alla stazioneWMO-GAW di Mt. Cimone (2165 m asl)
No full textMt. Cimone (44°11′N, 10°42′E) è il picco più elevato degli Appenninisettentrionali, ed ospita una stazione globale WMO-GAW rappresentativa dellecondizioni di troposfera libera nella regione sud-europea/mediterranea, attualmenteidentificata come hot-spot in termini sia di cambiamento climatico che di qualitàdell’aria. A partire dal 1998 e fino al 2011, dati di aerosol atmosferico infrazione PM10 sono stati raccolti alla stazione tramite un campionatore ad altovolume. Dopo il campionamento, i filtri sono stati sottoposti a gravimetria e aspettrometria-γ ad alta risoluzione per la determinazione della massa sospesa e di7Be e 210Pb, radionuclidi naturali di origine contrastante (infatti il primo èoriginato in stratosfera/alta troposfera da reazioni nucleari di spallazione, mentreil secondo deriva dal decadimento di 222Rn di provenienza crostale). A Mt. Cimone, ilPM10 esibisce una forte fluttuazione stagionale con un minimo invernale ed un massimoestivo. L’influenza delle aree sorgente di PM10 viene discussa per confronto condati simultanei raccolti in stazioni di pianura a nord e a sud della catenaappenninica. In genere, il PM10 mostra un gradiente verticale negativo con la quota,con Mt. Cimone che rappresenta il valore medio minimo. Il confronto delle serietemporali di PM10 con quelle di densità numeriche di particelle fini e grossolane el’impiego di una tecnica statistica basata sulle retrotraiettorie rivelanol’influenza dei trasporti da regioni sorgente quali il Nord Africa, la PianuraPadana ed il continente europeo inclusa l’area balcanica. L’andamento stagionalee le aree sorgente di 210Pb, che con il PM10 ha in comune gran parte del terminesorgente (la crosta terrestre), sono risultati in gran parte confrontabili. Perentrambe le serie temporali, ed in analogia a quanto riscontrato per PM10 e PM2.5 inaltre stazioni remote europee, è stato identificato un trend in diminuzione la cuiorigine è attualmente oggetto di indagine da parte degli autori
A PRELIMINARY SURVEY OF THE ANALYSIS OF NATURAL AND ARTIFICIAL RADIONUCLIDES IN SAMPLES COLLECTED IN ROSS BAY, ANTARCTICA
No full text137Cs distribution was determined by high resolution gamma-ray spectroscopy in sediment and soil samples from Terra Nova Bay , Antarctic
DISTRIBUTION OF CS-137 IN LAKE-SEDIMENTS AND SURROUNDING SOILS AT TERRA-NOVA BAY ANTARCTICA
No full textRadioactivity data (Bq/kg) from sea bottom and lake sediment samples collected in the 1987-88, 1988-89 and 1989-90 Italian expeditions in Antarctica are presented. Vertical distribution of Cs-137 in lake sediment cores and soil pits collected in the 1989-90 Expedition are discussed, together with the resulting inventories of the radionuclide; comparisons with literature data concerning both specific activities and inventories are also reported
Correlation between trace metal concentrations in sediments and in the mussel Mytilus Galloprovincialis
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