Stato attuale del ghiacciaio del Mandrone (Adamello) e fattori climatici

Riassunto Premesse alcune considerazioni generali si descrivono alcuni particolari fenomeni osservati al ghiacciaio del Mandrone e dovuti al rapido arretramento della fronte e assottigliamento del ghiaccio come: strozzatura della lingua ghiacciaio di rimpasto, ghiacciaio morto, lago alla bocca, crepacci circolari, valle ad U. Si fanno alcune considerazioni sul futuro andamento climatico alpino.

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Summary After some general considerations, there are described some particular phenomena noticed about the glacier of Mandrone (Adamello). They are due to the swift retirement of the front and to the diminution of the thickness of the glacier as following: the strangling of the icetongue, glacier rigenerated, glacier dead, lake at the glacier-mouth, round ice-crevices, valley like U. They are done some suppositions on the future alpine-climatical proceeding.

     

La realta' fisica del ciclo climatico di 5,6 anni

Riassunto Date le condizioni perchè un ciclo climatico possa considerarsi una realtà fisica ed esaminate le analisi periodali di lunghe serie di elementi climatici si mette in evidenza l'esistenza, la notevole ampiezza e la realtà fisica del ciclo di 5,6 anni. Esso si presenta sempre, in tutti i fattori geofisici e in tutte le regioni della terra. E' molto ampio, spesso più di ogni altro. Mantiene costante il periodo; la fase varia con la regione. Presenta particolari smorzamenti di carattere universale.

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Summary The conditions are given to a climatic cycle in order to have a physically reality. To 30 long series of annual values of climatic elements has been applied the periodal analysis after the method of Vercelli. In all the cases results with strong evidence a remarkable oscillation of 5,6 years. Attention is drawn to the physically reality of that cycle. It has an amplitude often greater that all other component-waves; the period remains almost constant, the phase change from region to region.

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Zusammenfassung Es werden die Bedingungen, damit ein klimatischer Cyklus als eine physische Realität betrachtet werden kann, angegeben. Man untersucht die periodalen Analysen von längeren Reihen klimatischer Elemente und es wird die Existenz, die bemerkenswerte Amplitude und die physische Realität des 5,6 jährigen Cyklus angedeutet. Derselbe ist immer vorhanden, in allen geophysischen Faktoren und in allen Erdteilen. Der Cycklus hat eine grosse Amplitude, ofter mehr als jeder andere. Behält constant seine Periode. Die Phase wechselt je nach der Zone. Er stellt im allgemeinen eigenartige Dämpfungen vor.

     

Analisi periodale della successione dei numeri relativi delle macchie solari

Riassunto Alla successione dei numeri relativi delle macchie solari (numeri di Wolf) si applica il procedimento dell'analisi periodale delVercelli e si eseguisce la scomposizione completa del diagramma. Si ottengono onde componenti di anni 16,0-11,15-8,32-5,68-4,05-2,9-2,0 e altre di periodi più lunghi ma meno precisi. Esse hanno caratteri di quasi-periodicità e di quasipersistenza. Si determinano le loro ampiezze e si confrontano con quelle corrispondenti dei cicli climatici terrestri.

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Summary To the series of the sun-spot relative-numbers (Wolf-numbers) has been applied the periodal analysis after the method ofVercelli. From this are derived component waves of 16,0-11,15-8,32-5,68-4,05-2,9-2,0 years and others with periods longer but less precise. They have almost-periodical and almost-persistent characters. Theirs amplitudes are determinated in Wolf's units. The waves found by these means are compared with the corresponding waves of the climatical cycles.

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Zusammenfassung An der Reihe der Relativzahlen der Sonnenflecke (Wolfer-Relativzahlen) wird dieVercelli Periodalanalyse angewendet. Es folgt die ganze Zerlegung. Man erhält Komponentwellen, die Perioden von 16,0-11,15-8,32-5,68-4,05-2,9-2,0 Jahren und andere mit längeren, aber umbestimmten Perioden, haben. Sie haben fast-periodische und fast-bestehende Kennzeichen. Es wird ihre Amplitude bestimmt. Dieselben Komponenten werden mit den entsprechenden Wellen der klimatischen Zyklen verglichen.

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Lavoro eseguito con il contributo del Consiglio Nazionale delle Ricerche.     

MHYDAS‐Erosion: a distributed single‐storm water erosion model for agricultural catchments

In this paper, we present MHYDAS‐Erosion, a dynamic and distributed single‐storm water erosion model developed as a module of the existing hydrological MHYDAS model. As with many catchment erosion models, MHYDAS‐Erosion is able to simulate sediment transport, erosion and deposition by rill and interrill processes. Its originality stems from its capacity to integrate the impact of land management practices (LMP) as key elements controlling the sedimentological connectivity in agricultural catchments. To this end, the water‐sediment pathways are first determined by a specific process‐oriented procedure defined and controlled by the user, which makes the integration of LMP easier. The LMP dynamic behaviours are then integrated into the model as a time‐dependent function of hydrological variables and LMP characteristics. The first version of the model was implemented for vegetative filters and tested using water and sediment discharge measurements at three nested scales of a densely instrumented catchment (Roujan, OMERE Observatory, southern France). The results of discharge and soil loss for simulated rainfall events have been found to acceptably compare with available data. The average R² values for water and sediment discharge are 0·82 and 0·83, respectively. The sensitivity of the model to changes in the proportion of LMP was assessed for a single rain event by considering three scenarios of the Roujan catchment management with vegetative filters: 0% (Scenario 1), 18% (Scenario 2, real case) and 100% (Scenario 3). Compared to Scenario 2 (real case), soil losses decreased for Scenario 3 by 65% on the agricultural plot scale, 62% on the sub‐catchment scale and 45% at the outlet of the catchment and increased for Scenario 1 by 0% on the plot scale, 26% on the sub‐catchment scale and 18% at the outlet of the catchment. Copyright © 2010 John Wiley & Sons, Ltd.     

Sources and distribution of organic matter in northern Patagonia fjords,Chile (∼44–47°S): A multi-tracer approach for carbon cycling assessment

We investigated the provenance of organic matter in the inner fjord area of northern Patagonia, Chile (～44–47°S), by studying the elemental (organic carbon, total nitrogen), isotopic (δ¹³C, δ¹⁵N), and biomarker (n-alkanoic acids from vascular plant waxes) composition of surface sediments as well as local marine and terrestrial organic matter. Average end-member values of N/C, δ¹³C, and δ¹⁵N from organic matter were 0.127±0.010, ?19.8±0.3‰, and 9.9±0.5‰ for autochthonous (marine) sources and 0.040±0.018, ?29.3±2.1‰, and 0.2±3.0‰ for allochthonous (terrestrial) sources. Using a mixing equation based on these two end-members, we calculated the relative contribution of marine and terrestrial organic carbon from the open ocean to the heads of fjords close to river outlets. The input of marine-derived organic carbon varied widely and accounted for 13–96% (average 61%) of the organic carbon pool of surface sediments. Integrated regional calculations for the inner fjord system of northern Patagonia covered in this study, which encompasses an area of ～4280 km², suggest that carbon accumulation may account for between 2.3 and 7.8×10⁴ ton C yr^?1. This represents a storage capacity of marine-derived carbon between 1.8 and 6.2×10⁴ ton yr^?1, which corresponds to an assimilation rate of CO₂ by marine photosynthesis between 0.06 and 0.23×10⁶ ton yr^?1. This rate suggests that the entire fjord system of Patagonia, which covers an area of ～240,000 km², may represent a potentially important region for the global burial of marine organic matter and the sequestration of atmospheric CO₂.     

Benchmarking sustainability in cities: The role of indicators and future scenarios

Scenarios are a useful tool to help think about and visualise the future and, as such, are utilised by many policymakers and practitioners. Future scenarios have not been used to explore the urban context in much depth, yet have the potential to provide valuable insights into the robustness of decisions being made today in the name of sustainability. As part of a major research project entitled Urban Futures, a toolkit has been developed in the UK to facilitate the use of scenarios in any urban context and at any scale relevant to that context. The toolkit comprises two key components, namely, (i) a series of indicators comprising both generic and topic area-specific indicators (e.g., air quality, biodiversity, density, water) that measure sustainability performance and (ii) a list of characteristics (i.e., 1–2-sentence statements about a feature, issue or small set of issues) that describe four future scenarios. In combination, these two components enable us to measure the performance of any given sustainability indicator, and establish the relative sensitivity or vulnerability of that indicator to the different future scenarios. An important aspect of the methodology underpinning the toolkit is that it is flexible enough to incorporate new scenarios, characteristics and indicators, thereby allowing the long-term performance of our urban environments to be considered in the broadest possible sense.     

The role of pre-existing faults in the structural evolution of thrust systems: Insights from the Ligurian Alps (Italy)

New structural and stratigraphic data for a selected area of the Ligurian Alps are combined in order to assess and discuss the role played by extensional structures in the southernmost segment of the Western Alps during thrusting. Restored cross-sections and field data suggest that the structural style in the external sector of the chain may depend upon the presence of pre-orogenic normal faults ascribed to three extensional events linked to different geodynamic contexts: (i) Permian post-Variscan plate reorganisation, (ii) Mesozoic rifting–drifting phases leading to the opening of the Alpine Tethys, and (iii) Eocenic development of the European foreland basins. During positive inversion in Eocene times, a thin-skinned thrust system developed in this area, followed by a thick-skinned phase. In both situations the inherited extensional structures played fundamental roles: during the thin-skinned phase they conditioned the thrusting sequence, also producing large-scale buckle folds and partial reactivations; during the thick-skinned phase the strain was compartmentalized and partitioned by pre-existing faults.The kinematic model of the external sectors of the Ligurian chain also allows the re-assessment of the Alpine evolution of the front-foreland transition, including: (i) indirect confirmation that in the Eocene the Ligurian Briançonnais and Dauphinois domains were not separated by the Valais-Pyrenean oceanic basin; (ii) that the thin-skinned phase progressively changed into thick-skinned; (iii) the assertion that there were no significant deformations from the Oligocene to the present-day, and the Corsica–Sardinia block rotation only produced a change in orientation of previously formed structures and normal fault system development.     

Simulations of the Madden–Julian oscillation in four pairs of coupled and uncoupled global models

The status of the numerical reproduction of the Madden–Julian Oscillation (MJO) by current global models was assessed through diagnoses of four pairs of coupled and uncoupled simulations. Slow eastward propagation of the MJO, especially in low-level zonal wind, is realistic in all these simulations. However, the simulated MJO suffers from several common problems. The MJO signal in precipitation is generally too weak and often eroded by an unrealistic split of an equatorial maximum of precipitation into a double ITCZ structure over the western Pacific. The MJO signal in low-level zonal wind, on the other hand, is sometimes too strong over the eastern Pacific but too weak over the Indian Ocean. The observed phase relationship between precipitation and low-level zonal wind associated with the MJO in the western Pacific and their coherence in general are not reproduced by the models. The seasonal migration in latitude of MJO activity is missing in most simulations. Air–sea coupling generally strengthens the simulated eastward propagating signal, but its effects on the phase relationship and coherence between precipitation and low-level zonal wind, and on their geographic distributions, seasonal cycles, and interannual variability are inconsistent among the simulations. Such inconsistency cautions generalization of results from MJO simulations using a single model. In comparison to observations, biases in the simulated MJO appear to be related to biases in the background state of mean precipitation, low-level zonal wind, and boundary-layer moisture convergence. This study concludes that, while the realistic simulations of the eastward propagation of the MJO are encouraging, reproducing other fundamental features of the MJO by current global models remains an unmet challenge.

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VST OmegaCAM difference image analysis

We present a modified version of the difference image analysis software developed by the OGLE collaboration (DIAPL) and its implementation within AstroWISE environment. Python interface and parallel execution are described. Examples of graphical output on simulated data set are presented. The tool will be used in VST surveys for photometric variability search.