Analysis of recent meteorological configurations responsible for substantial snowfalls in the Trentine sector of the Adige valley bottom (eastern italian Alps).

Aim of this presentation is to analyse the synoptic conditions favourable to snowfall with more than 10 cm fresh snow cover in the bottom of the Trentine sector of the Adige Valley. Following the abundant and reiterated snowfalls in the study area during the 2005-2006 winter season and the many discomforts to the population and mainly to the road traffic, an accurate study of such events resulted necessary for a reliable forecast. The valley orientation in a NNE-SSW direction lets the Mediterranean warm-humid air masses to get in as far as the main headwater divide (Brenner Pass) and to make its climate relatively mild. Moreover, such humid air inflows bring mean annual precipitation of about 800-1000 mm that gradually decreses from the lower valley mouth to the main divide. The precipitation regime consists of rainfalls in spring and autumn whereas a strong absolute minimum occurs between December and Febraury when snowfalls are more likely on the valley floor. In fact, the vally is annually subjected to warm advection snowfalls, though infrequent and scarce, between November and mid April. The study area is about 80 km long with elevation ranging from 130 and 230 m a.s.l. All the snowfall events observed from 1980 to 2006 were analysed by using the data of the Civil Protection Authority of Trento Province, i.e. Trento Roncafort (194 n a.s.l.), Trento Laste (312 m a.s.l.), Rovereto (203 m a.s.l.) and Ala (197 m a.s.l.) meteo stations. Through the study and analysis of ground and at the 500 hPa geopotential meteo maps, satellite images, thermodynamic diagrams of the nearest sounding stations and the data of the nivometeorological stations, the synoptic types that characterised the snowfalls were studied and classified and a clusterisation was made. For each of the synoptic types defined the conditions for a quantification of the mean characteristic meteo parameters were anlysed in order to obtain a reliable forecast of intense snowfalls on the valley bottom

Tendenza evolutiva della spiaggia della Riserva Naturale della Sentina (San Benedetto del Tronto, AP)

Abstract The Regional Natural Reserve “Sentina” stretches itself for some 1.7 km along the southernmost end of the littoral area of San Benedetto del Tronto (AP) at the boundary with Abruzzo; it hosts one of the very few costal dunes still preserved in the Marche Region. Its gravelly-sandy beach in still natural, but is bound to the north by a long series of emerged barriers and to the south by a long (more than 300 m) pier; these structures noteworthy influence the retreat of the shoreline. In the area, a long monitoring (starting from 2000) has been carried out in order to interpret and quantify the modification occurred on both the emerged and submerged beach. During this time span, the shoreline retreated every year: up to 2006 its retreat has been evaluated in 27.7 m, with a local maximum of 33.5 m, whilst for the following 6 years (notwithstanding an artificial nourishment in 2008) it continued to retreat by 22.2, as an average. Therefore, in 12 years wave erosion resulted in some 50 m of backing; this also implied the loss of about 42’000 m2 of coastal dunes. Therefore, it is logical to assume that if no relevant intervention will be carried out, standing the almost absent nourishment deriving from the solid load of the Tronto R., in the next future the Sentina area will suffer progressive coastal erosion, with severe backing of the shoreline and distruction of the coastal dunes. Keywords: coastal erosion, monitoring, “Sentina” Reserve, coastal dune

Gli effetti antropici nell’evoluzione storica della costa “Picena”

The historical evolution of the southern Marche shoreline (between the Conero promontory and the Tronto R. mouth) has been investigated comparing it with both natural and anthropic changes. The study started searching, georeferencing and digitizing in a GIS environment all the available historical maps and the observations deriving from archeological and documental findings, in order to reconstruct the position of the shoreline at different times, mostly for fluvial mouths. This allowed us to highlight that for the last two millennia anthropic interventions influenced coastal dynamics more than climate variations. For all the investigated sites a close relation between shoreline fluctuations and forestation/deforestation processes was clearly revealed. Among others, it emerged that river mouths progradation continued up to 1930, well after the end of the “Little Ice Age” (around 1850). The above relation is particularly striking for the last two centuries, for which we have both accurate maps and census of forested areas. During the XIX century, notwithstanding the warm climate favored slope protection, widespread deforestation resulted in a regular advance of shorelines (average rate about 4.95 m/y for the first half of the century and 1.08 m/y for the second half). The XX century featured a more irregular behavior with substantial retreat after the ‘30s: this derives almost exclusively from anthropic interventions in the river basins (construction of dams, river bed quarrying, river reshaping, abandonment of crops etc.) leading to a severe decrease of solid load. For the last few decades and at present, the most important factors driving the behavior of coastlines resulted to be the various interventions carried out along the beaches and in front of them to reduce erosion. Keywords: antropogenic impact, historical evolution, coastline, central-southern Marche, Adriatic Se

Considerazioni sull’utilizzo delle sabbie dragate al largo di Civitanova Marche (Adriatico centrale) per il ripascimento delle spiagge.

Sono state analizzate le principali caratteristiche dei sedimenti dragati al largo di Civitanova Marche (Adriatico centrale), confrontandole con quelle degli arenili delle Marche meridionali al fine di evidenziare la lor compatibilità. Particolare attenzione è stata dedicata all'analisi del sito di Marina Palmense (Comune di Fermo) in cui nel luglio 2007 il materiale dragato è stato utilizzato per un primo ripascimento. Dallo studio è risultata l'incompatibilità dei materiali dragati con la dinamica costiera lungo quasi tutto il tratto investigato, compreso quello già sottoposto a rifluimento, dimostratosi inefficace