Top PDF Karst subsidence in South-Central Apulia, Southern Italy

Karst subsidence in South-Central Apulia, Southern Italy

Karst subsidence in South-Central Apulia, Southern Italy

The latter features, and particularly the presence of underground cavities produced by dissolution of soluble rocks, make karst a highly fragile and delicate environmen[r]

19 Read more

Karstic aquifer vulnerability assessment methods and results at a test site (Apulia, southern Italy)

Karstic aquifer vulnerability assessment methods and results at a test site (Apulia, southern Italy)

The Murgia (maximum height 680 m a.s.l.) is a large asymmetric horst affected by two neotectonic fault systems (NW-SE and NE-SW). Because of these faults, the morpho- logical structure slopes down towards the Adriatic Sea and towards the adjoining regions, by means of a succession of step-shaped ledges bounded by small fault throws. The karst environment consists of platform Cretaceous limestone and dolostone covered with thin layers of Pliocene-Quaternary rocks and soils. The carbonate rock is bedded, jointed, and subject to karst phenomena (Polemio, 2005). The test site (Fig. 2), as large portions of Murgia, is characterised by developed karst landforms that form a network due to the chemical dissolution of limestone (Grassi, 1983). As a re- sult, an underground network of cavities, caves, and con- duits has developed, some of which are very large (Regione Puglia a ). The landscape is typically low-relief karst, charac- terised by many dolines and by very flat-bottom valleys (lo- cally called lame) filled with thin alluvial deposits; mainly residual clayey deposits from karst processes (the so-called terre rosse) and detritus. Outside the test site in the south- western Murgia sector, typical deep canyon valleys, called gravine, can be observed (Parise and Pascali, 2003). Valleys and water lines are the remnants of the original hydrographic network, which is discontinuous at present. The high Mur- gia plateau (higher than 300 m a.s.l.) is dominated by clear karstic features and by the existence of discontinuous and thin topsoil layers (less than 50 cm, mainly residual clayey soils and limestone pebbles). Moving from the inland to the Adriatic coast and decreasing in altitude, the shallow karstic features are less evident due to the progressively more con- tinuous and often thicker topsoil cover (Provincia di Bari; Regione Puglia, 1999).
Show more

10 Read more

Flood history in the karst environment of Castellana-Grotte (Apulia, (southern Italy)

Flood history in the karst environment of Castellana-Grotte (Apulia, (southern Italy)

The disastrous effects of the 1896 flood, as well as of those that preceeded it, were favoured by actions of mismanage- ment of the territory, starting from deforestation of the hills around Castellana, severely carried out since 1700. Defor- estation was mostly performed to provide wood for heat- ing during the winter season or for industrial activities, and to conquer new pieces of land to agriculture. This phe- nomenon was very typical of large areas of the Mediter- ranean Basin, where it was favoured by expansion of settle- ments and agricultural practices, which eventually resulted in promoting soil degradation (Gams, 1991; Gams et al., 1993; Frumkin, 1999; Gams and Gabrovec, 1999). In south- ern Italy, where extensive deforestation occurred in the 18th and 19th centuries, many hydro-geomorphological problems (mostly shallow landslides and erosion) have still to be re- lated to destruction of the vegetational cover that was origi- nally present on slopes (Sorriso Valvo, 1993; Parise and Wa- sowski, 2000).
Show more

12 Read more

Intrinsic vulnerability assessment of the south-eastern Murge (Apulia, southern Italy)

Intrinsic vulnerability assessment of the south-eastern Murge (Apulia, southern Italy)

Abstract. Maps of areas with different vulnerability degrees are an integral part of environmental protection and manage- ment policies. It is difficult to assess the intrinsic vulnera- bility of karst areas since the stage and type of karst struc- ture development and its related underground discharge be- haviour are not easy to determine. Therefore, some improve- ments, which take into account dolines, caves and superficial lineament arrangement, have been integrated into the SIN- TACS R5 method and applied to a karst area of the south- eastern Murge (Apulia, southern Italy). The proposed ap- proach integrates the SINTACS model giving more weight to morphological and structural data; in particular the following parameters have been modified: depth to groundwater, effec- tive infiltration action, unsaturated zone attenuation capacity and soil/overburden attenuation capacity. Effective hydro- geological and impacting situations are also arranged using superficial lineaments and karst density. In order to verify the reliability of the modified procedure, a comparison is made with the original SINTACS R5 index evaluated in the same area. The results of both SINTACS index maps are compared with karst and structural features identified in the area and with groundwater nitrate concentrations recorded in wells. The best fitting SINTACS map is then overlaid by the layout of potential pollution centres providing a complete map of the pollution risk in the area.
Show more

6 Read more

Cryptokarst: A Case-Study of the Quaternary Landforms of Southern Apulia (Southern Italy)

Cryptokarst: A Case-Study of the Quaternary Landforms of Southern Apulia (Southern Italy)

INTRODUCTION In this paper, the first results about Quaternary cryptocorrosion forms occurring in the Apulia region (southern Italy) are reported. In particular, the research focus on forms developed on Plio- Pleistocene porous soft-rocks. Formerly, Nicod (1976) and Fabre & Nicod (1986) indicated some cryptocorrosion surfaces developed on the Mesozoic limestone in this region. Along the Adriatic coastal area and in the central part of Salento, some grike-like forms (Jennings, 1987) and solution pipes (Jennings, 1987), both filled with reddish sands and silts, are formed on these rocks. Apulian pipes have been described by several authors (Maxia, 1950; Blanc & Cardini, 1961; Rudnicki, 1980; Parenzan, 1983; Delle Rose & Parise, 2003). The pipes developed on Pliocene calcarenites at Roca have been interpreted as fossilized trunk casts by Blanc & Cardini (1961). According to Delle Rose & Parise (2003) these pipes formed by solution pans deepening or karst hole enlargement; the filling accumulated later. Similar pipes developed on the lower Pleistocene calcarenites along the Villanova coast have been interpreted as singenetic forms produced by the groundwater downflow to the sea (Rudnicki, 1980). Till now, the pipes have been neither interpreted as cryptocorrosion forms nor ascribed to a single morphogenetic phase.
Show more

13 Read more

LONG-TERM EVENT STRATIGRAPHY OF THE APULIA PLATFORM MARGIN (UPPER JURASSIC TO EOCENE, GARGANO, SOUTHERN ITALY)

LONG-TERM EVENT STRATIGRAPHY OF THE APULIA PLATFORM MARGIN (UPPER JURASSIC TO EOCENE, GARGANO, SOUTHERN ITALY)

The Late Jurassic was a time of rapid subsidence and widespread plat- form growth on the margins of the central North Atlantic and of the Li- gurian Ocean (western Tethys). However, these carbonate platforms were drowned and their growth suddenly interrupted during the Valanginian. This phenomenon and the associated drowning unconformities are well known in a large part of world, from the Caribbean to eastern Arabia. The Valanginian drowning is documented (see references in Bosellini and Mor- silli 1997) in: (1) the western continental margin of the Atlantic Ocean (Scotian Shelf, Baltimore Canyon, Caribbean); (2) the eastern continental margin of the Atlantic Ocean (Iberia, Morocco); (3) the western peri-Alpine domain, i.e., the northern and western continental margin of the Ligurian Ocean and the margin of Iberia (southern France, Helvetic Alps, Estre- madura, eastern Prebetic and Betic areas); and (4) the margins of the Adria Plate (Apulia Platform). Recently, additional data have been presented by Stoll and Schrag (1996). According to these authors, strontium-isotope data from the deep ocean (Blake–Bahama Basin, off the eastern coast of United States) from an interval spanning 7 million years in the Berriasian–Valan- ginian would imply that global sea level fluctuated about 50 meters over time scales of 200,000 to 500,000 years.
Show more

12 Read more

Day care cataract surgery in Central and Southern Italy: a multicentric survey

Day care cataract surgery in Central and Southern Italy: a multicentric survey

In Italy, even in the absence of up-dated studies about the diffusion of DS for cataract surgery [25-28], national data [14] show a marked increase over recent years in the out- patient/inpatient admission rate for "Cataract Surgery" (27% in 1999, 38% in 2000, 47% in 2001, 62% in 2002 and 74% in 2003), especially in Northern and Central Italy but with some regional differences [9]. In particular, in the regions investigated in our survey, the outpatient/ inpatient admission rates for cataract surgery obtained from the "Hospital Discharge Report" Database of the Ministry of Health [14] were: Lazio from 16% in 1999 to 72% in 2003; Molise from 0% in 1999 to 23% in 2003; Campania from 1% in 1999 to 46% in 2003; Puglia from 7% in 1999 to 55% in 2003; Sicily from 14% in 1999 to 75% in 2003. These rates and the observed trend agree with our results updated to 2005. Moreover, these data suggest that day cataract surgery rates are ubiquitously increasing but that there is still substantial variation among regional health districts.
Show more

6 Read more

Caves and karst-like features in Proterozoic gneiss and Cambrian granite, southern and central Sri Lanka: An introduction

Caves and karst-like features in Proterozoic gneiss and Cambrian granite, southern and central Sri Lanka: An introduction

There has been little study of the geology and geomorphology of the caves and karst­like features developed in the Proterozo­ ic gneiss and Cambrian granite of Sri Lanka. This lack of study is surprising given that caves and rockshelters in these rocks contain significant archaeological and cultural sites. Caves and karren, both mimicking those developed in carbonate rocks, have formed both in gneiss, which is the dominant rock type of the Proterozoic crust of the island and in granite. In addition to overhangs, boulder caves, soil pipes and tectonic caves, tunnel caves, arch caves and block breakdown caves of significant size are developed in siliceous rocks in Sri Lanka. while metamor­ phosed dolomites are interfoliated within the gneissic suite, simple removal of carbonate by solution from within the sur­ rounding rock cannot account for all or most of the speleogen­ esis observed. while spalling and breakdown are responsible for cave enlargement, cave initiation is probably due to either phreatic solution of silicates and/or phantom rock processes. Speleothems and cave minerals including silicates, phosphates, gypsum, carbonates and niter are found in the caves. Active silicate speleothems are not restricted to joints and fissures and suggest that solution of silicates is currently occurring within the body of the rock in the vadose zone. while guano is the likely source of the phosphate, sulfate and nitrate, the source of the calcium in the carbonates remains unclear. Caves in the intrusive and metamorphic rocks of Sri Lanka are enigmatic. They are unexpectedly similar in appearance to their carbon­ ate karst counterparts. Continuing research will allow them to hold a mirror to our understanding of speleogenesis, mineral­ ization and sedimentation in carbonate karst caves.
Show more

24 Read more

Basement uplift and basin subsidence in Central Australia

Basement uplift and basin subsidence in Central Australia

The model adopted here builds upon the work of Lister et al (1986, 1987). A major flat zone of extensional detachment is envisaged to separate an upper plate, showing minimal signs of extension except at its margins, from a highly stretched lower plate. Earlier extensional models of this type incorporated detachment zones, envisaged to be low-angle normal faults, which cut through the entire lithosphere (Fig. 5-6 (a); compare with Wernicke, 1985). Extensional models combining flat detachment zones with pure shear extension of the lower crust and mantle (Fig. 5-6 (b)) lead to the horizontal transfer of lithospheric extension across the zone of detachment, giving rise to major lateral separation of regions of upper plate extension (upper crust) from regions of extension in the lower plate (lower crust and mantle) (Wernicke, 1985). As a consequence, syn- and post-rift subsidence can be offset from surface rifting and eventually from the continental margin highly structured by rifting (Fig. 5-6 (c)). In the case of extreme extension, the zone of ductile stretching in the lower plate will rise towards the surface (Fig. 5-6 (d)). If flat detachment zones develop at mid-crustal levels and near the Moho, the sub-crustal lithosphere can be stretched and pulled from beneath the crustal upper plate without extending the overlying crustal plate (Fig. 5-6 (e)). A ramp syncline (basin) may form in the hanging wall side in the step of the detachment zone as it switches from mid-crustal to Moho depths (Fig. 5-6 (f)). Marginal plateaux can result from these mid-crustal detachment zones developing below weakly extended upper crust. Transfer faults (Gibbs, 1984) accommodate substantial differences in along-strike displacement or rapid changes on the level of detachment. Steps between levels of detachment produce synclines or ramp basins (Gibbs, 1984), on the hanging wall side of the ramp where it steps down from a mid-crustal level to Moho depths. Flexing of the upper plate is required to maintain the constraint of plane-strain.
Show more

209 Read more

Analysis of vegetation diversity in relation to the geomorphological characteristics in the Salento coasts (Apulia - Italy)

Analysis of vegetation diversity in relation to the geomorphological characteristics in the Salento coasts (Apulia - Italy)

We here present a phytosociological study of the plant biodiversity of the coastal environments of an area of the Italian peninsula (the Salento peninsula – Apulia), in relation to the variations of the geomorphological characteristics. In particular, the low sandy coast environments were examined, with an analysis of the populations making up the vegetation successions of the xeroseres and hygroseres, the sandy coasts plated on hard calcarenitic rocks, the low calcarenitic cliffs and the limestone cliffs. This study has allowed the recognition of a high number of plant communities that are in chain contact on the same geomorphological context, and that determine the psammophilous, halophilous and subhalophilous chain successions characterizing the different coastal plant landscapes. This knowledge on succession will be important in the reconstruction of the coastal environments that have been strongly degraded by the human impact.
Show more

14 Read more

Epilithic diatom assemblages and environmental quality of the Su Gologone karst spring (central-eastern Sardinia, Italy)

Epilithic diatom assemblages and environmental quality of the Su Gologone karst spring (central-eastern Sardinia, Italy)

The comparison between our list of species and that re- ported by Dell’Uomo (1990) indicated considerable differ- ences in the Su Gologone spring after 25 years, with the presence of 21 taxa in common in both studies, 29 taxa de- tected only in the previous study and 68 taxa observed only in this study. The latter included 25 new records for the spring and more in general for running waters of Sardinia. The differences found seem mostly due to advances of tax- onomic knowledge because several taxa like Navicula anto nii, Navicula vilaplanii, Diploneis separanda, Gom- phonema angustius, Amphora indistincta, Amphora meridi- onalis, Amphora vetula, were described some years after the study carried out in 1985–1986. Except for the tempera- ture, previous environmental data of the spring are not available. However, differences found could be also related with environmental changes. In fact, species like Campylo- discus hibernicus, Cymbella helvetica, Encyonema elgi- nense, Cyclotella ocellata, Navicula radiosa, (xenosaprobic and characteristic of hypotrophic or ultraoligotrophic envi- ronments) were not detected during our investigation, and nor were Planothidium ellipticum and Diatoma hyemalis, the only two taxa belonging to the nordic-alpine fl ora (Dell’Uomo 1990). In the central Apennines, D. hyemalis is reported as a species “at risk of extinction”. It seems to be increasingly rare and exclusively located at high altitudes, in cold well-oxygenated waters, and with a fast current (Torrisi and Dell’Uomo 2009). A longer study could ascer- tain the real state of P. ellipticum and D. hyemalis in the Su Gologone spring, also taking into account a possible effect of global warming on these cold water stenotherm species.
Show more

15 Read more

Identifying Karst Aquifers Recharge Area Using Environmental Isotopes: Case Study in Central Italy

Identifying Karst Aquifers Recharge Area Using Environmental Isotopes: Case Study in Central Italy

Water stable isotopes are conservative tracers of groundwater, related to rainfalls isotopic composition before infiltration. In the aim of identifying the recharge areas of karst springs under study [20], it has been chosen GW1 spring, which has the highest outcropping elevation in the hydrogeological basin (1057 m a.s.l.), that is reasonably closer than other ones, in its groundwater isotopic content, to the rainfall value [13]. Thus, for GW1 spring, according to equation (4) it has been calculated the average infiltration elevation, weighted according to the effective infiltration values, obtained by the application of the Inverse Hydrogeological Balance Water Method (Figure 5):
Show more

14 Read more

Ethnophytotherapeutical research in the high Molise region (Central-Southern Italy)

Ethnophytotherapeutical research in the high Molise region (Central-Southern Italy)

nary science (or in all sectors of ethnobotanical knowl- edge) of each area by the number of species of the respective floras [21,55,56]. We can note (see Table 3) that the values of E.I. in the selected Italian areas are between 3.83 % and 10,75 % (upper Molise, Acquap- endente, Maratea) [36,37,51-53]. Instead, the values for the entire country [54] are higher (from 14.24 % to 17.57 %). These Italian values of E.I. are generally lower than the corresponding ones for Spanish, perhaps due to a more rapid process of cultural erosion in Italy. Nevertheless, it appear that the indexes of the Spanish areas were calcu- lated, according Portères, on all the plants used by the informants or at least on the plants known and for which the informants gave a name, and not only on medicinal plants (J. Vallès, personal communication). Complete folk knowledge of plants is greatly appreciated in scien- tific ethnobotanical research in Spain, also by pharmaco- botanists, while in Italy many aspects of this research are often entrusted to the good will of single researchers. Medicinal uses
Show more

11 Read more

Landslides, floods and sinkholes in a karst environment: the 1–6 September 2014 Gargano event, southern Italy

Landslides, floods and sinkholes in a karst environment: the 1–6 September 2014 Gargano event, southern Italy

The study area covers approximately 1600 km 2 and encom- passes the Gargano Promontory that extends for a few tens of kilometres into the Adriatic Sea, in the NE part of the Puglia region, southern Italy (Fig. 1). The Lesina and Varano coastal lakes separate the northern side of the promontory from the sea. Elevation in the area ranges from sea level to 1056 m a.s.l. with a mean value of about 400 m, and mor- phology is controlled by E–W- and NW–SE-trending faults (Funiciello et al., 1988; Brankman and Aydin, 2004). Due to the presence of a well-developed karst environment, surface hydrography is limited to a few short ephemeral drainages along the slopes that bound the elevated central plateau, and to the Candelaro River and minor drainages in the al- luvial and coastal plains surrounding the promontory. In the area, sedimentary rocks crop out, chiefly carbonate platform limestone, limited marl and residual “terra rossa” deposits (Bosellini et al., 1999). Soils, where present, are chromic Cambisols and Luvisols. Yearly cumulated rainfall ranges between 400 and 1200 mm, and mean annual air tempera- ture varies from 10 to 17 ◦ C. The climate is Mediterranean to Mediterranean suboceanic. July and August are dry, and most of the precipitation falls as rainfall from September to November (Polemio and Lonigro, 2011). The promontory hosts the Gargano National Park and a number of towns and
Show more

14 Read more

The influence of the geological setting on the morphogenetic evolution of the Tremiti Archipelago (Apulia, Southeastern Italy)

The influence of the geological setting on the morphogenetic evolution of the Tremiti Archipelago (Apulia, Southeastern Italy)

Field evidence, such as E–W trending right lateral transtension faults cross-cutting Pliocene and late Miocene formations (Funiciello et al., 1988), sets of en-´echelon R shears and horizontal slickensides in the San Domino Fm. (Doglioni et al., 1996), support a right-lateral move- ment along the E–W Tremiti alignment to the North of the Gargano Promontory (Doglioni et al., 1994). It is an active E–W trending right lateral transtensional fault interpreted as a boundary between two blocks of the Adria microplate with different thickness and tectonic regimes (Calcagnile and Panza, 1981; Mosetti and Mosetti, 1984, Favali et al. 1990; 1993; Console et al., 1993; Mongelli et al., 1994). Indeed, since the middle Pleistocene period, the southern Adriatic block (Apulia foreland and Bradanic foredeep), made up of a continental lithosphere about 110 km thick, began to up- lift ( ∼ =0.5 mm/yr) while the northern Adriatic block (cen- tral Adriatic sea), with a thinner continental lithosphere of about 70 km, was characterised by a high subsidence rate (greater than 1 mm/yr) (Ciaranfi et al., 1983; Suhadolc and Panza, 1989). In the west dipping subduction of the Adria
Show more

13 Read more

Coupled decadal variability of the North Atlantic Oscillation, regional rainfall and karst spring discharges in the Campania region (southern Italy)

Coupled decadal variability of the North Atlantic Oscillation, regional rainfall and karst spring discharges in the Campania region (southern Italy)

The long-term declining linear trend over the whole ob- served time period of the MAPI was in accordance with the findings of other authors for precipitation in southern Italy (Cotecchia et al., 2003; Polemio and Casarano, 2008; Ducci and Tranfaglia, 2008; Brandimarte et al., 2011). In ad- dition, by observing the 11-yr moving average pattern with respect to the normal value (mean value of the whole time se- ries), a complex cyclical dynamic was recognised (Fig. 2b). Two phases characterised by values above the normal value were identified in the periods 1930–1944 and 1958–1978, and three phases below the normal value were identified in the years preceding 1930 and in the periods 1944–1958 and 1980–2005. These long-term fluctuations were found as in- versely coincident with those of the winter NAOI (Fig. 2a). Interestingly, for the last part of the time series, an increased frequency of MAPI values below the average value, which were not reached during previous periods, demonstrated a downward shifting trend. From 1985 to 2008, negative val- ues (down to < − 30 % in 1992) were continuously observed, except in 1995, 1996 and 2005. Similar low levels also oc- curred in the 1930s and the 1940s (1932 and 1946) but with lower frequency (Fig. 2b). The maximum values of the time series were as follows: +31 % (1933), +35 % (1969) and +41 % (2010).
Show more

11 Read more

Plant communities of travertine outcrops of the Saturnia area in southern Tuscany (central Italy).

Plant communities of travertine outcrops of the Saturnia area in southern Tuscany (central Italy).

Brought to you by | Università degli Studi di Firenze Authenticated | daniele.viciani@unifi.it author's copy Download Date | 6/6/13 3:03 PM... Phillyrea latifolia, Rosa sempervirens and [r]

24 Read more

A zinc, copper and citric acid biocomplex shows promise for control of Xylella fastidiosa subsp. pauca in olive trees in Apulia region (southern Italy)

A zinc, copper and citric acid biocomplex shows promise for control of Xylella fastidiosa subsp. pauca in olive trees in Apulia region (southern Italy)

The effectiveness of Dentamet® was tested for three consecutive years (2015, 2016 and 2017). The ex- perimental plot included two facing blocks of 20 trees each (20 treated and 20 untreated trees). Each block contained ten Ogliarola salentina and ten Cellina di Nardò trees, in randomized positions along each row. At the beginning of the trial, the mean incidence and severity of disease did not differ between the two blocks (i.e., 20% of trees showed symptoms with 10% severity). Dentamet® was sprayed on the canopy of the trees using an atomizer, with the rate of the com- pound being equivalent to 3.9 L ha -1 (280 mL in 100 hL of water). At each treatment, each tree received at least 20 L of spray solution. Six spray treatments were applied in each year, commencing in early April and ceasing in October, but avoiding July and August (Supplementary Table 2). No other treatments to con- trol pests or pathogens were supplied to the trees dur- ing the trials. Control trees did not receive any Den- tamet® treatments during the three consecutive years. However, compounds routinely applied for control- ling the main diseases and pests (olive peacock spot, olive knot, olive fruit fly) were applied to the control plants. Assessments of disease through spring, sum- mer and autumn were made by counting, at each sur- vey and for each tree of each cultivar, the total num- ber of wilted twigs and branches through the whole tree canopy. This method allowed precise estimates of disease progression during the seasons by revealing also the possible twig re-sprouting upon application of treatments. Data were subjected to ANOVA. Mean values were compared by Fisher’s LSD test at (P<0,05). Two-way analyses of variance (ANOVA) were also performed on mean monthly values to assess effects of cultivar and the cultivar × treatment interaction. Statistical analyses were performed using SPSS soft- ware package, version 20.0 (SPSS Inc.). Climate data of the area were obtained from the Rete Agrometeoro- logica Regionale of Apulia Region-Assocodipuglia, Salice salentino (LE) station (Lat: 40°23ʹ26ʺN; 17°52ʹ 31ʺE), checked by ACCREDIA.
Show more

25 Read more

Hominin responses to environmental changes during the Middle Pleistocene in central and southern Italy

Hominin responses to environmental changes during the Middle Pleistocene in central and southern Italy

Potential long-distance movements do not seem to be an efficient model for hominin communities settled in central and southern Italy. In fact, long-distance mobility was lim- ited to the east and the west by the Adriatic and Tyrrhenian seas, and then would have been directed northward. How- ever, the climate of northern Italy during the Middle Pleis- tocene was significantly colder and drier with respect to the southern and central regions due to its latitudinal position and proximity to the Alps’ ice sheet (Bertini, 2010; Palombo and Sardella, 2007; Corrado and Magri, 2011; Manzi et al., 2011), and this would have constrained human groups to fundamentally modify their behaviour in order to face rad- ically different environments. Successive human adaptations to environmental changes after each phase should be de- tected within the cultural evolution, but the local evidence has not been recorded to date (Grifoni and Tozzi, 2005; Peretto, 2006; Doronichev and Golovanova, 2010). An op- posite hypothesis could be that the cultural evolution was linked to southward movements of northern populations to- wards central and southern Italy (Grifoni and Tozzi, 2005; Peretto, 2006; Doronichev and Golovanova, 2010; Manzi et al., 2011). Thus, the milder climate conditions recorded in central and southern Italian peninsula, compared to northern parts of Europe, may have constituted attractive areas for al- lochtonous populations, leading to cultural developments and demographic expansions.
Show more

11 Read more

Tropospheric Circulation Variability over Central and Southern South America

Tropospheric Circulation Variability over Central and Southern South America

The annual average of PC1 also shows a positive trend (significant at 95% level), Figure 12(a), which basi- cally comes from winter months. The number of annual cases over (below) the average plus (minus) one stan- dard deviation is presented in Figure 12(b) and Figure 12(c); there is a positive (negative) and significant trend in the cases corresponding to the positive (negative) phase of Mode 1 superposed to a noticeable interdecadal variability. The positive phase predominates during winter months and, as explained in Section 3, distinguishes from the average winter in a marked northward low level flow over central and eastern Argentina. This flow brings warm air to this region and so, the mean areal temperature calculated from for the region above described for the period May-September has a strong annual correlation with PC4, namely 0.76. This correlation is still high and significant, 0.72, when both series that have significant positive trends are detrended. This means that there is a relationship between both variables, which does not depend of an eventual casual coincidence of trends. At the same time, this fact, together with the physics associated, implies that this regional temperature trend is at least partially due to the change in the circulation associated to Mode 1. This does not allow discarding global warming as the main driver of this local warming, since it may be also the cause of the local circulation trend.
Show more

24 Read more

Show all 10000 documents...

Related subjects