Tabelle per il calcolo delle derivate seconde del potenziale relativo a settori di anelli cilindrici omogenei

Riassunto Le tabelle numeriche contenute in questa Nota, costruite per facilitare il calcolo delle derivate seconde del potenziale generato da masse che si possono scomporre in settori di anelli cilindrici omogenei coassiali con la verticale del punto di stazione, sono precedute da brevi cenni sul loro impiego e sulle formole assunte a fondamento di esse.

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Zusammenfassung Zur Berechnung der zweiten partiellen Ableitungen des Schwerepotentials von Massen welche sich in gleichartige zylindrische Ringsektoren, konzentrisch mit der Vertikallinie der Station (Nullpunkt), zerlegen lassen, gibt der Verf. zwei numerische Tafeln, die diese Rechnungen erleichtern. Erläuterungen betreffs der Formeln die zu Grunde gelegt wurden und die betreffenden Anwendungsmöglichkeiten der angegebenen numerischen Wertestehen den Tafeln voran.

     

The Gulf of California: Review of ecosystem status and sustainability challenges

The Gulf of California is unique because of its geographical location and conformation. It hosts diverse ecosystems and important fisheries that support industry and provide livelihood to coastal settlements. It is also the site of interests and problems, and an intense interaction among managers, producers, and conservationists. In this report, we scrutinize the abiotic (hydrography, climate, ocean circulation, and chemistry) and biotic (phyto- and zooplankton, fish, invertebrates, marine mammals, birds, and turtles) components of the marine ecosystem, and some particular aspects of climate variability, endemisms, harmful algal blooms, oxygen minimum layer, and pollution. We also review the current conditions and conflicts around the main fisheries (shrimp, small and large pelagic fishes, squid, artisanal and sportfishing), the most important human activity in the Gulf of California. We cover some aspects of management and conservation of fisheries, especially the claimed overexploitation of fish resources and the ecosystems, and review proposals for creating networks of marine protected areas. We conclude by identifying main needs for information and research, particularly the integration of data bases, the implementation of models and paleoreconstructions, establishment of monitoring programs, and the evaluation of fishing impacts and management actions.     

Biogeochemistry of surface sediments off Concepción (∼36°S), Chile: El Niño vs. non-El Niño conditions

We compared the signals of several water column properties (upwelling intensity, sea level anomaly, temperature, nutrients, dissolved oxygen, chlorophyll-a, and surface sediments) of the continental shelf off Concepción (36°S) during the 1997-1998 El Niño with those of a normal year (2002-2003). We found that the primary hydrographic effect of El Niño 1997-1998 was a reduction in the input of nutrient-rich, oxygen-poor Equatorial Subsurface Water over the shelf. This affected the biology of the water column, as evidenced by the reduced phytoplankton biomass. Surface sediment properties (biogenic opal, organic carbon, bulk δ¹⁵N) observed during El Niño 1997-1998 reflected a reduced export production and the sediments failed to show the water column seasonality that occurs under normal conditions. In addition, weakened denitrification and/or upper water column fertilization could be inferred from the sedimentary δ¹⁵N. Although diminished, export production was preserved in the surface sediments, revealing less degraded organic matter in the upwelling period of the El Niño year than in the normal year. We suggest that the fresher organic material on the seafloor was probably associated with a severe reduction in the polychaete Parapronospio pinnata, which is considered to be the most important metazoan remineralizer of organic carbon at the sediment-water interface in the study area.     

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.