Bemerkungen zum säkularen Gang der Temperatur im Südpolargebiet

Zusammenfassung Im Hinblick auf gegensätzliche Resultate vonWillett undScherhag wird gezeigt, daß im Gegensatz zum Nordpolargebiet in der Antarktis nicht auf eine eindeutige säkulare Temperaturänderung in den letzten Jahrzehnten geschlossen werden kann. Die Feststellungen dieser Autoren lassen sich teilweise durch Ungenügen oder Zufälligkeiten der Berechnungsmethode erklären.

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Summary It is shown, with a view to contradictory results ofWillett andScherhag, that for the Antarctic it cannot be concluded to a clear secular change of temperature in the past decades, contrary to the north polarzone. The results of these authors may be explained partly by insufficience or accidentalness in the methods of calculation.

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Résumé En discutant les résultats contradictoires obtenus parWillett etScherhag, l'auteur explique que, contrairement à la région polaire arctique, on ne peut clairement conclure qu'un changement séculaire de la température ait eu lieu dans l'Antarctique pendant les dernières décades. Les constatations faites par ces auteurs s'expliquent, partiellement par l'insuffisance ou par des hasards de la méthode de calcul.

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A two-stage time series model for monthly hydrological projections under climate change in the Lim River basin (southeast Europe)

ABSTRACT

Climate change projections of precipitation and temperature suggest that Serbia could be one of the most affected regions in southeastern Europe. To prepare adaptation measures, the impact of climate changes on water resources needs to be assessed. Pilot research is carried out for the Lim River basin, in southeastern Europe, to predict monthly flows under different climate scenarios. For estimation of future water availability, an alternative approach of developing a deterministic-stochastic time series model is chosen. The proposed two-stage time series model consists of several components: trend, long-term periodicity, seasonality and the stochastic component. The latter is based on a transfer function model with two input variables, precipitation and temperature, as climatic drivers. The Nash-Sutcliffe model efficiency for the observed period 1950–2012 is 0.829. The model is applied for the long-term hydrological prediction under the representative concentration pathway (RCP) emissions scenarios for the future time frame 2013–2070.     

Reforestation Programs in Southwest China： Reported Success, Observed Failure, and the Reasons Why

Ever since the disastrous floods of 1998, the Chinese government has used the Natural Forest Protection and Sloping Land Conversion Programs to promote afforestation and reforestation as means to reduce runoff, control erosion, and stabilize local livelihoods. These two ambitious programs have been reported as large-scale successes, contributing to an overall increase in China’s forest cover and to the stated goals of environmental stabilization. A small-scale field study at the project level of the implementation of these two programs in Baiwu Township, Yanyuan County, Sichuan, casts doubt upon the accuracy and reliability of these claims of success; ground observations revealed utter failure in some sites and only marginal success in others. Reasons for this discrepancy are posited as involving ecological, economic, and bureaucratic factors. Further research is suggested to determine whether these discrepancies are merely local aberrations or represent larger-scale failures in reforestation programs.     

The Požarevac loess–paleosol sequence: a record of increased aridity in the south-eastern margin of the Carpathian Basin during the last 350 ka

The loess sequence preserved in the Požarevac brickyard in north-eastern Serbia comprises eight loess units separated by seven paleosols. Geochronological investigation using amino acid racemization and luminescence dating support stratigraphic correlations of loess units L3, S2LL1 and L1 at the Požarevac section with loess of glacial cycles E [Marine Isotope Stage (MIS) 10], D (MIS 9–8), C (MIS 7–6) and B (MIS 5–2) across central Europe. Correlation with the marine oxygen-isotope stratigraphy and associated paleoclimatic inferences are further supported by magnetic susceptibility, particle size and carbonate content measured in Požarevac sediments. Malacological investigations at the Požarevac section reveal the continuous presence of the Chondrula tridens and Helicopsis striata faunal assemblages throughout the last 350 ka. The loess malacological fauna, which is characterized by the complete absence of cold-resistant and cold-preferring species, suggests a stable, dry and relatively warm glacial and interglacial climate, compared with other central European loess localities. Together these data suggest that the south-eastern part of the Carpathian (Pannonian, Middle Danube) Basin was a refugium for warm-preferring and xerophilous land-snails during the generally unfavorable glacial climates of the late Middle and Late Pleistocene.     

Statistical Analysis of Water Quality Parameters in Seven Major Serbian Rivers during 2004‒2013 Period

Rivers on territory of the Republic of Serbia can be separated to three sea drainage basins: Black, Adriatic and Aegean. Majority of rivers belong to the Black Sea drainage basin. The Danube is the most important river in Serbia and one of the most important rivers of Europe. All rivers investigated in this paper represent direct or indirect tributaries of the Danube River and as that, they are belonging to the Black Sea drainage basin. In this study, the water quality status and the spatial and temporal trends of seven major rivers in Serbia were assessed through the application of ten parameters of Water Quality Index. Ten year (2004–2013) public database of environmental data was used. Into considerations were taken differences between every river individually and difference between sample positions on every single river. Based on the chemical parameters of water quality, it can be seen that the biggest rivers in Serbia show different values of WQ parameters. The highest WQ value is measured on the Drina River, while the lowest value is measured on the Ju?na Morava and the Tisza River. Analyses of parameters per period of year show that there is a statistically significant difference between values during warm and cold periods.     

Heat wave risk assessment and mapping in urban areas: case study for a midsized Central European city,Novi Sad (Serbia)

Risk assessment and mapping methodologies for heat waves as frequently occurring hazards in central and southeastern Europe were applied in this study, and the impact of heat waves on the mortality of urban populations was determined as part of the assessment. The methodology for conducting the heat wave risk assessment is based on European Commission’s Guidelines for Risk Assessment and Mapping. The Novi Sad (Serbia) urban area was studied during summer 2015, which was one of the hottest summers in the last few decades. In situ air temperature measurements from urban stations and mortality of urban populations were used. Nocturnal urban heat island (UHI) intensity values between the various built-up zones and natural surrounding areas were used for the hazard level calculation. Temperature data from 9 p.m. to 5 a.m. were used because during the night, the UHI intensity reached its maximum values. The average daily number of deaths by LCZs was used to define the impact level of the vulnerability index. Calculations for both hazard levels were completed during two intensive heat waves (in July and August 2015) when it was expected that there may be a high level of risk. The results and maps show that the urban area is complex, and the heat wave risk on the population is not uniform. The most densely built-up areas (LCZs 2, 5 and 6) have very high or high risk values that are influenced by a higher rate of mortality. The obtained results and maps can be used by local authorities to prevent and mitigate climate-related hazards, for medical institutions as well as urban planners and for ancillary local, regional or national services. According to these results, the local authorities could define hot spots where they can place medical and rescue teams and install points with water supplies, etc.     

Cold and warm air temperature spells during the winter and summer seasons and their impact on energy consumption in urban areas

The main objective of this study is to determine and analyze cold and warm air temperature spells in the last 6 years (2007–2012) and reveal their impact on electrical energy consumption in a small-sized city such as Sombor (Serbia) with less than 50,000 inhabitants. Hourly air temperature values and electrical energy consumption data have been used as database for all methods. Warm and cold temperature spells (during heat and cold waves) have had the increasing tendencies in the last 6 years and they reflect on additional electrical energy consumption. Detailed analysis showed that higher energy demands occur during workdays and daytime period. Monitoring of the amount of consumed energy showed a clear relationship during the winter cold temperature spells, when electrical energy demand was higher than 0.3 MW. In summer period, the relationship was weaker and consumption was higher than 0.15 MW only when temperature exceeded 30 °C. A small number of air condition devices in houses and companies and mainly one-store buildings with thick walls, which make a good insulation from the outside air temperatures, are probably the main reasons for the above-mentioned results in summer. This paper introduces a new method to resolve the problem of short-term load forecasting, based on the support vector machines (SVM) technology and particle swarm optimization that has been used to optimize the SVM parameters. Similar-day-based forecast has shown that similar days for training should be filtered also using classifier of temperature period (cooling degree-days or heating degree-days in a row). Forecasting error is smaller compared to solutions where similar days are found only on season and temperature.     

Influence of human pressure on forest resources and productivity at stand and tree scales: The case study of Yunnan pine in SW China

This paper examines human impact on stands and individual trees of Pinus yunnanensis growing near the small mountain villages of Pianshui and Yangjuan in southwestern Sichuan Province,China.In an effort to assess whether use of these forests was sustainable,we examined the effects of human use in two ways.First,we directly measured the effect of cutting branches,for fuel and fodder,on tree growth.We hypothesized that branch cutting would negatively impact tree growth.We established 12 plots on four hills and compared 14 pairs of trees,one tree in each pair with an apparently full crown and the other with a considerable portion of the crown removed.Second,we assessed stand and tree properties over a 500 m elevation gradient above the villages where we hypothesized that as elevation increases,stand and tree properties should show fewer human impacts.Although extensive branch cutting reduced the live crown,tree height and diameter,compensatory processes likely enabled trees to recover and to add basal area increments(BAIs) similar to those added by trees with full crowns.Trees and stands close to villages showed less growth and lower basal areas,respectively,than stands and trees at intermediate or distant elevations from villages.Areas relatively close to the villages showed considerable effects of human-related disturbances such as branch cutting,grazing,tree and shrub removal,losses of litter,and human and animal trails.Such areas had increased soil erosion and often loss of the ‘A’ horizon.Stands close to villages had younger trees,lower stand basal areas,smaller basal area increments,and more stumps.Our results suggest an increasingly vulnerable interface between occupants of these two villages and their surrounding forests.     

Quartz from Allchar as monitor for cosmogenic 26Al: Geochemical and petrogenetic constraints

Summary Results of a multidisciplinary study on quartz concentrates (mineralogically separated) and etched concentrates (stoichiometric quartz) from three locations at Allchar (Macedonia) are presented. The investigation of quality and composition of these quartz samples is of great interest because the same material has been previously used as monitor for ²⁶Al Acceleration Mass-Spectrometry (AMS) erosion rate estimates. Two genetically different types of quartz are distinguished in the studied samples which petrologically can be described as hydrothermally altered dacites or quartz latites; i.e. volcanic (Q_V) and hydrothermal (Q_H) quartz with relative proportions of Q_H:Q_V around 3:2. Q_H is genetically related to the Allchar Sb–As–Tl–S mineralization having very high Sb (85–785 ppm), As (7.6–78 ppm) and (Tl 3.3–4.0 ppm) contents. This type of quartz is also characterized by very high Li (129–138 ppm), Al (2424–2520 ppm) and Ti (153–219 ppm) concentrations. Q_V appears to be much less enriched in trace elements having Al and K contents ranging from 0 to 280 ppm and from 50 to 85 ppm, respectively. ²⁶Al AMS measurements were done on the samples containing two genetically different types of quartz but this had no effects on the interpretation and erosion rate determinations. However, the extremely high Al concentrations in the analyzed quartz have generally negative effects, mainly by decreasing ²⁶Al/²⁷Al ratios and thus causing an increase of the detection limit. The disagreement between the results of ²⁶Al AMS analyses and quantitative geomorphologic data for one location is probably caused by different geographical position with respect to the direction of cosmic rays.     

Zur Frage der Klimaänderung in der Polarzone des Südatlantiks

Zusammenfassung Die seit 1903 lückenlosen Beobachtungen der argentinischen Station auf den Süd-Orkney-Inseln zeigen keine einsinnige Klimaäderung. Es läßt sich nur eine in allen Elementen gut ausgeprägte Witterungsschwankung in der zweiten und dritten Dekade dieses Jahrhunderts erkennen. Ein ähnliches thermisches Verhalten weisen auch die Malvinen und Südgeorgien auf. Da auch keine einsinnige Temperaturänderung auf je einer Insel im Ost- und Westpazifik festgestellt werden konnte, bedürfen die Behauptungen, daß es sich bei der auf der Nordhalbkugel zweifellos stattgefundenen Temperaturerhöhung um eine weltweite Erscheinung handle, einer Korrektur.

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Summary The continuous records of meteorlogical observations since 1903 at the Argentine station on the South-Orkney-Islands indicate no change of the climate in one sense; all elements show only an oscillation in the second and third decade of this century. A similar thermal characteristic is confirmed for Islas Malvinas (Falkland-Islands) and for South-Georgia. During the same period no uniform change of temperature could be found neither in the Eastern Pacific represented by Juan Fernandez (West of Chile) nor in New Zealand (Western Pacific). Therefore the suposition that the rise of temperature has been a world-wide phenomenon, needs some correction for the southern hemisphere, though the fact has been proved for the northern.

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Resumen La ininterrumpida serie de observaciones meteorológicas, efectuadas desde el año 1903 en las Islas Orcadas del Sud, demuestra que durante ese lapso no se produjio ningún cambio definido del clima. Hubo únicamente oscilaciones simultáneas en los elementos climáticos durante la segunda y tercera década de este siglo. Se comprueba un comportamiento térmico similar para las Islas Malvinas y Georgia del Sud. Consta, además, que durante el mismo período no hubo ningún cambio definido del régimen térmico ni en el Océano Pacífico Oriental, representado por la Isla Juan Fernández, ni en el Pacífico Occidental, representado por Nueva Zelandia. En consecuencia debe revisarse la hipótesis que el aumento de la temperatura, comprobado sin lugar a dudas en lo que va de nuestro siglo para el hemisferio norte, constituye un fenómeno mundial.

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Résumé Des observations continues effectuées dès 1903 à la station argentine des Orcades du Sud démontrent qu'aucun changement uniforme du climat y a eu lieu depuis cette époque. Uniquement pendant la 2^ème et 3^ème décade du siècle une oscillation du climat en tous ses éléments a été remarquée. Une réaction thermique analogue se présente pour les Malouines et la Géorgie du Sud. Il n'est non plus possible de constater une variation uniforme sur l'île Juan Fernandez (pacifique oriental) ni à la Nouvelle Zélande. Il s'ensuit que l'accroissement indiscutable des températures sur l'hémisphère nord ne peut être regardé comme mondial, puisqu'il n'a pas été constaté pour l'hémisphère sud.

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