Littérature scientifique sur le sujet « Climatic tracers »
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Articles de revues sur le sujet "Climatic tracers"
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Jull, J. T., G. S. Burr, J. W. Beck, et al. "Accelerator Mass Spectrometry at Arizona: Geochronology of the Climatic Record and Connections with the Ocean." Scientific World JOURNAL 2 (2002): 1579–93. http://dx.doi.org/10.1100/tsw.2002.349.
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There are many diverse uses of accelerator mass spectrometry (AMS).14C studies at our laboratory include much research related to paleoclimate, with14C as a tracer of past changes in environmental conditions as observed in corals, marine sediments, and many terrestrial records. Terrestrial records can also show the influence of oceanic oscillations, whether they are short term, such as ENSO (El Niño/Southern Oscillation), or on the millennial time scale. In tracer applications, we have developed the use of129I as well as14C as tracers for nuclear pollution studies around radioactive waste dump sites, in collaboration with IAEA. We discuss some applications carried out in Tucson, AZ, for several of these fields and hope to give some idea of the breadth of these studies.
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Krinner, G., and C. Genthon. "Tropospheric transport of continental tracers towards Antarctica under varying climatic conditions." Tellus B: Chemical and Physical Meteorology 55, no. 1 (2003): 54–70. http://dx.doi.org/10.3402/tellusb.v55i1.16354.
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KRINNER, G., and C. GENTHON. "Tropospheric transport of continental tracers towards Antarctica under varying climatic conditions." Tellus B 55, no. 1 (2003): 54–70. http://dx.doi.org/10.1034/j.1600-0889.2003.00004.x.
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Baker, A. R., W. M. Landing, E. Bucciarelli, et al. "Trace element and isotope deposition across the air–sea interface: progress and research needs." Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences 374, no. 2081 (2016): 20160190. http://dx.doi.org/10.1098/rsta.2016.0190.
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The importance of the atmospheric deposition of biologically essential trace elements, especially iron, is widely recognized, as are the difficulties of accurately quantifying the rates of trace element wet and dry deposition and their fractional solubility. This paper summarizes some of the recent progress in this field, particularly that driven by the GEOTRACES, and other, international research programmes. The utility and limitations of models used to estimate atmospheric deposition flux, for example, from the surface ocean distribution of tracers such as dissolved aluminium, are discussed and a relatively new technique for quantifying atmospheric deposition using the short-lived radionuclide beryllium-7 is highlighted. It is proposed that this field will advance more rapidly by using a multi-tracer approach, and that aerosol deposition models should be ground-truthed against observed aerosol concentration data. It is also important to improve our understanding of the mechanisms and rates that control the fractional solubility of these tracers. Aerosol provenance and chemistry (humidity, acidity and organic ligand characteristics) play important roles in governing tracer solubility. Many of these factors are likely to be influenced by changes in atmospheric composition in the future. Intercalibration exercises for aerosol chemistry and fractional solubility are an essential component of the GEOTRACES programme. This article is part of the themed issue ‘Biological and climatic impacts of ocean trace element chemistry’.
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Lu, Dawei, Jihua Tan, Xuezhi Yang, Xu Sun, Qian Liu, and Guibin Jiang. "Unraveling the role of silicon in atmospheric aerosol secondary formation: a new conservative tracer for aerosol chemistry." Atmospheric Chemistry and Physics 19, no. 5 (2019): 2861–70. http://dx.doi.org/10.5194/acp-19-2861-2019.
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Abstract. Aerosol particles are ubiquitous in the atmosphere and affect the quality of human life through their climatic and health effects. The formation and growth of aerosol particles involve extremely complex reactions and processes. Due to limited research tools, the sources and chemistry of aerosols are still not fully understood, and until now have normally been investigated by using chemical species of secondary aerosols (e.g., NH4+, NO3-, SO42-, SOC) as tracers. Here we investigated the role of silicon (Si), an ubiquitous but relatively inert element, during the secondary aerosol formation process. We analyzed the correlation of Si in airborne fine particles (PM2.5) collected in Beijing – a typical pollution region – with the secondary chemical species and secondary particle precursors (e.g., SO2 and NOx). The total mass of Si in PM2.5 was found to be uncorrelated with the secondary aerosol formation process, which suggested that Si is a new conservative tracer for the amount of primary materials in PM2.5 and can be used to estimate the relative amount of secondary and primary compounds in PM2.5. This finding enables the accurate estimation of secondary aerosol contribution to PM2.5 by using Si as a single tracer rather than the commonly used multiple chemical tracers. In addition, we show that the correlation analysis of secondary aerosols with the Si isotopic composition of PM2.5 can further reveal the sources of the precursors of secondary aerosols. Therefore, Si may provide a new tool for aerosol chemistry studies.
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Casciotti, Karen L. "Nitrite isotopes as tracers of marine N cycle processes." Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences 374, no. 2081 (2016): 20150295. http://dx.doi.org/10.1098/rsta.2015.0295.
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Nitrite (NO 2 − ) is a key intermediate in the marine nitrogen (N) cycle. It is produced and consumed throughout the ocean by the dominant processes driving the distribution, availability and speciation of N. However, the accumulation of nitrite is typically confined to depths near the base of the sunlit euphotic zone and in oxygen-deficient zones. These features are known as the primary and secondary nitrite maximum (PNM and SNM), respectively. The processes controlling nitrite accumulation in these features are not fully understood, but are thought to depend on the microbial community composition and its response to environmental conditions. A variety of approaches have been applied to understanding these features since their discovery, with the stable N and oxygen (O) isotope measurements of nitrite being added to this toolkit most recently. Large variations in nitrite N isotope ratios ( 15 N/ 14 N) and dramatic depletions in 15 N contrast with more consistent nitrite O isotope ratios ( 18 O/ 16 O) in the SNM. These signals provide unique information about the mechanisms of nitrite consumption in the SNM. By contrast, nitrite in the PNM shows less variation in 15 N/ 14 N, but variations in 18 O/ 16 O that provide insight into the mechanisms and rates of N cycling there. This review presents a synthesis of nitrite isotope measurements in the marine environment, highlighting the insights that have been gained from these measurements. This article is part of the themed issue ‘Biological and climatic impacts of ocean trace element chemistry’.
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Padmaja, Suragani Mohini, Sagiraju Dileep Kumar Varma, Koduri Omkar, and Gajula Srinivasa Rao. "Real time performance assessment of utility grid interfaced solar photovoltaic plant." International Journal of Electrical and Computer Engineering (IJECE) 14, no. 2 (2024): 1323. http://dx.doi.org/10.11591/ijece.v14i2.pp1323-1333.
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Continuous monitoring of large-scale solar photovoltaic (PV) installations is necessary to check the deterioration and monitor the performance of the PV plant. Fault diagnosis is crucial to ensure the PV plant operates safely and reliably. This paper presents a diagnosis methodology based on current-voltage (I-V) and PV characteristics to monitor and assess the behavior of solar PV. In this paper, I-V curve characterization using an I-V curve tracer is used to check the deterioration and diagnosis of the PV panels. The real-time performance of the 50.4 kWp rooftop solar grid interfaced PV plant is investigated and analyzed using I-V and PV curve tracers in real-time conditions. The overall performance of solar PV is assessed on a real-time test system in different scenarios such as variable climatic conditions, partial shading conditions, aging of solar panels, short circuit conditions, and dust decomposition. Furthermore, the performance assessment of solar PV is evaluated using performance indicators such as open circuit voltage index, short circuit current index, fill factor, and performance ratio.
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Tateo, Fabio. "Clay Minerals at the Paleocene–Eocene Thermal Maximum: Interpretations, Limits, and Perspectives." Minerals 10, no. 12 (2020): 1073. http://dx.doi.org/10.3390/min10121073.
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The Paleocene–Eocene Thermal Maximum (PETM) was an “extreme” episode of environmental stress that affected the Earth in the past, and it has numerous affinities concerning the rapid increase in the greenhouse effect. It has left several biological, compositional, and sedimentary facies footprints in sedimentary records. Clay minerals are frequently used to decipher environmental effects because they represent their source areas, essentially in terms of climatic conditions and of transport mechanisms (a more or less fast travel, from the bedrocks to the final site of recovery). Clay mineral variations at the PETM have been studied by several authors in terms of climatic and provenance indicators, but also as tracers of more complicated interplay among different factors requiring integrated interpretation (facies sorting, marine circulation, wind transport, early diagenesis, etc.). Clay minerals were also believed to play a role in the recovery of pre-episode climatic conditions after the PETM exordium, by becoming a sink of atmospheric CO2 that is considered a necessary step to switch off the greenhouse hyperthermal effect. This review aims to consider the use of clay minerals made by different authors to study the effects of the PETM and their possible role as effective (simple) proxy tools for environmental reconstructions.
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Pitari, G., and E. Mancini. "Short-term climatic impact of the 1991 volcanic eruption of Mt. Pinatubo and effects on atmospheric tracers." Natural Hazards and Earth System Sciences 2, no. 1/2 (2002): 91–108. http://dx.doi.org/10.5194/nhess-2-91-2002.
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Abstract. Large explosive volcanic eruptions are capable of injecting considerable amounts of particles and sulphur gases (mostly sulphur dioxide) above the tropopause, causing increases in the stratospheric aerosol optical depth that may be even larger than one order of magnitude. The e-folding particle lifetime in the stratosphere is much longer than in the troposphere (one year versus a few days) so that climatic perturbations in a timeframe of a few years are produced after major volcanic eruptions. A climate-chemistry coupled model is used here to study the dynamical effects of the radiative forcing due to stratospheric aerosols formed after the June, 1991 cataclysmic eruption of Mt. Pinatubo in the Philippines. It is shown that the dynamical perturbation is twofold: (a) the stratospheric mean meridional circulation is affected by local aerosol radiative heating (mostly located in the tropical lower stratosphere); (b) the planetary wave propagation in the mid- to high-latitude lower stratosphere is altered as a consequence of decreasing atmospheric stability due to the climatic perturbation. Dynamical results of the climate model are compared with available observations; a discussion is made regarding the similarities with the dynamical regime of the easterly phase of the equatorial quasi-biennial oscillation. Major findings of this study are: (a) radiatively forced changes in the stratospheric circulation during the first two years after the eruption may, to a large extent, explain the observed trend decline of long-lived greenhouse gases (CH4 and N2O, in particular); (b) the dynamical perturbation helps explain why simple photochemical studies of the ozone trends during 1991–1993 generally fail in reproducing the satellite observed feature consisting of a 2% additional global ozone depletion during 1993 with respect to 1992. In both cases we conclude that an increase in the mid- to high-latitude downward flux at the tropopause is the key factor for explaining the behaviour of these atmospheric tracers during 1991/92.
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Nerushev, A. F., K. N. Visheratin, and R. V. Ivangorodsky. "Satellite-derived estimations of the clear-air turbulence in the upper troposphere." IOP Conference Series: Earth and Environmental Science 1040, no. 1 (2022): 012025. http://dx.doi.org/10.1088/1755-1315/1040/1/012025.
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Abstract The paper presents the results of a study of turbulence zones in the upper troposphere of the Northern Hemisphere based on measurements from European geostationary meteorological satellites in 2007 - 2018. The essence of the method for determining the zones of turbulence is the use of inhomogeneity’s of concentration of water vapor as tracers and the use of correlation-extremal algorithms. Turbulence zones with a horizontal mesoscale turbulent diffusion coefficient Ked ≥ 104 m2 / s can occupy up to 50% of the Northern Hemisphere area visible from satellites. It is shown that in analyzed time interval there is a significant (by 60-120%) increase in areas occupied by relatively weak and moderate turbulence and a slight decrease (by 6-33%) in areas with strong and very strong turbulence. The temporal variability of these zones and their relationship with the characteristics of jet streams and some climatic parameters are analyzed. A statistical model of the temporal variability of the turbulence zone areas has been built. It is shown that the multiple linear regression model with jet stream characteristics as predictors describes up to 68% of variability of zones of strong turbulence. The use of climatic parameters as predictors makes it possible to describe up to 74% of the temporal variability of strong turbulence zones.
Thèses sur le sujet "Climatic tracers"
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Duvert, Clement. "Stream & groundwater responses to episodic recharge: Integrating time-series analysis & environmental tracers." Thesis, Queensland University of Technology, 2016. https://eprints.qut.edu.au/94989/12/Clement_Duvert_Thesis.pdf.
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This dissertation examines the hydrological response of aquifers and streams subjected to highly episodic recharge. Based on high-resolution measurements of a range of novel hydrochemical and isotopic tracers, it is demonstrated that (i) inter-aquifer mixing can be triggered by major recharge events and (ii) the transit time of the groundwater contribution to streams varies considerably with varying recharge rates. These findings suggest that stream–aquifer and inter-aquifer interactions are highly preferential both spatially and temporally, with important implications for the conceptualisation of hydrological processes in complex geological settings.
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Bouchet, Marie. "Coherent dating of deep polar ice cores and implications for understanding climate mechanisms." Electronic Thesis or Diss., université Paris-Saclay, 2024. http://www.theses.fr/2024UPASJ020.
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Les données paléoclimatiques fournissent des estimations empiriques des changements climatiques pré-anthropiques à des échelles de temps variées. Elles ont documenté des réchauffements globaux de la Terre (+5 à 10°C) se déroulant sur des milliers d'années tous les ~100 000 ans au cours du dernier million d'années, les déglaciations. Ces transitions sont particulièrement intéressantes pour les projections climatiques, car elles permettent d'estimer le taux de fonte des calottes glaciaires. Les données paléoclimatiques témoignent aussi d'événements plus rapides (quelques décennies), les "points de bascule", qui indiquent que le système climatique peut être déstabilisé significativement.Les forages polaires sont uniques car ils fournissent une mesure directe de la composition atmosphérique passée et permettent la reconstruction du climat local. Mon doctorat s'est concentré sur le forage EPICA Dome C (EDC) en Antarctique de l'Est, qui fournit le plus long enregistrement continu à ce jour. Il documente les changements climatiques qui se sont produits à l'échelle de quelques décennies à plusieurs milliers d'années au cours des derniers 800 000 ans. Alors que les isotopes de l'eau mesurés dans les archives glaciaires sont classiquement utilisés pour déduire les variations passées de la température et de précipitation locales, nous montrons que le δ¹⁵N de N2 mesuré dans les bulles d'air piégées dans la glace peut être utilisé de façon complémentaire. En effet, le δ¹⁵N de N2 reflète la profondeur de piégeage des bulles dans la glace, elle-même déterminée par la température et le taux d'accumulation de neige à la surface. Un nouvel enregistrement de δ¹⁵N de N2 est présenté. Il permet d'identifier précisément le phasage entre le CO₂ atmosphérique et le climat de l'Antarctique au cours des huit dernières déglaciations. Deuxièmement, j'ai développé une chronologie cohérente pour quatre forages situés en Antarctique et un forage au Groënland, couvrant les 800 000 dernières années. Cette chronologie a été construite à l'aide du modèle probabiliste Paleochrono-1.1 et est contrainte par de nouvelles mesures faites sur le forage EDC et par des données issues de modélisation glaciologique. L'incertitude de l'échelle d'âge d'EDC est réduite de 1700 à 900 ans en moyenne. La chronologie révisée est en meilleur accord avec des chronologies absolues obtenues de manière indépendante pour d'autres paléo-archives.Enfin, une méthodologie est proposée pour construire des chronologies cohérentes, relatives et absolues pour les archives marines et glaciaires au cours des sept dernières déglaciations. Elle permet d'identifier de manière plus précise l'ordre dans lequel se produisent les changements relatifs de l'insolation, de concentration atmosphérique en gaz à effet de serre, du niveau de la mer et des températures régionales lors des déglaciations. Dans une étude préliminaire, nous avons identifié une avance de quelques milliers d'années du CO2 sur le niveau marin lors des déglaciations. Des perspectives de recherche sont proposées pour atteindre une meilleure compréhension des relations de cause à effet entre le forçage externe et la réponse interne du climat.Mon travail de thèse a combiné la modélisation glaciologique et statistique, l'analyse expérimentale de l'air piégé dans la carotte de glace EDC ainsi que l'analyse de données paléoclimatiques issues d'archives polaires, de carottes sédimentaires marines et de spéléothèmes. Mes recherches contribuent à l'amélioration (i) des reconstructions climatiques à partir des forages polaires et (ii) des chronologies des forages polaires et marins. Ces avancées sont essentielles pour mieux comprendre la réponse du climat à un forçage externe lors des changements climatiques de grande amplitude, ce qui est essentiel pour prévoir les changements climatiques à venir<br>It is possible to gain insights from past climate natural variability in order to constrain the response of the climate system to change in the external forcing and future projections. Paleoclimate data provide empirical estimates of pre-anthropic large-scale climate change across a range of timescales, including the long timescales (several thousand years) associated with the glacial-interglacial transitions of great amplitude that affected Earth's climate every ~100 thousand years over the past million years. This is of particular interest for climatic projections, as it may allow for the estimation of the rate of ice cap melting. Furthermore, paleoclimate data can be employed to investigate "tipping point" events, which show the potential for rapid (over a few decades) and significant instabilities in the climate system. Among the paleo archives, deep polar ice cores are distinctive in that they offer direct records of ancient global atmospheric composition in greenhouse gases and documented past local changes in snowfall and temperature. My PhD focused on the EPICA Dome C (EDC) drilling site in East Antarctica which provides the oldest continuous ice core record so far. It documents climate change that occurred over a wide range of timescales (from a few decades to several thousands of years) over the past 800,000 years. While water isotopes are classically used to infer past temperature and accumulation rate when measured in ice cores, we show that δ¹⁵N of N2 measured in air bubbles trapped in ice core can be a complementary tool. δ¹⁵N of N2 indeed reflects the depth of bubble enclosure in the ice sheet, itself driven by surface temperature and snow accumulation rate at surface. A new record of δ¹⁵N of N2 over the last 800 kyr is presented and provides an accurate identification of the lead-lag relationship between atmospheric CO₂ and Antarctic climate over deglaciations. Secondly, I developed a precise, coherent timescale for five deep polar ice cores, spanning the past 800,000 years, known as the Antarctic Ice Core Chronology (AICC) 2023. This timescale is built using the probabilistic dating model Paleochrono-1.1 and constrained by new EDC measurements and glaciological modeling outputs. This permitted to reduce the average uncertainty of the EDC age scale from 1,700 to 900 years. The revised chronology aligns better with independent and absolute chronologies of other paleo archives.Furthermore, we proposed a methodology for constructing coherent, relative, and absolute chronologies for marine and glacial archives over past glacial-interglacial cycles. Evaluating the sensitivity of the coherent chronology to dating methodologies produced robust error bars, aiding in the precise identification of climatic event sequences (e.g. relative timing of changes in insolation, atmospheric greenhouse gases, global sea level, and regional temperatures) during glacial-interglacial transitions. In a preliminary study, we identify a few-year lead of atmospheric CO2 with respect to sea level in six of the seven latest deglaciations. Further research is needed to study the implications of such chronologies to understand the causal relationships between external forcing and the climate's internal response.My approach combined glaciological and statistical modeling with an experimental analysis of air trapped in EDC ice core and a data analysis of various paleo records from polar ice cores, marine sedimentary cores and speleothems. My research contributes significantly to improving climate reconstructions from ice cores, reducing dating uncertainties, and developing coherent chronological frameworks. These advancements enhance our understanding of the climate's response to an external forcing and of the interactions between different Earth System components during glacial-interglacial transitions
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Burn, Laurie. "Isotopic and elemental tracers in ice and snow as indicators of source regions of aerosols and changing environmental conditions." Thesis, Curtin University, 2009. http://hdl.handle.net/20.500.11937/152.
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Pioneering studies of lead (Pb) concentrations in polar ice by Clair C. Patterson and co-workers (e.g. Murozumi et al., 1969; Boutron and Patterson, 1983, 1986) revealed important information on climatic changes dating many thousands of years in the past and the effect that humans have had on these pristine environments. Rosman and co-workers (e.g. Rosman et al., 1993, 1994a) extended this research utilising the isotopic composition of Pb preserved in the ice to identify the source regions of both natural and anthropogenic Pb transported to the polar regions, thereby adding significantly to the understanding of atmospheric transport mechanisms and the impact of continental anthropogenic activity on the pristine polar environments. This thesis extends this area of research by investigating seasonal and short-term variability in Pb, Ba and In concentrations and Pb isotopes through the accurate sectioning of decontaminated glacial ice cores at high spatial resolution. This improves our understanding of the processes impacting on the deep ice core records, which, in turn, expands the interpretation and application of these records.A new sample preparation technique, incorporating a mechanised circular saw blade arrangement into the lathe design, first described by Candelone et al. (1994), has been developed to sample glacial ice cores at high spatial resolution with minimal contamination. This technique was extensively tested using artificially made ice cores, prepared from ultra-pure water, to quantify and minimise the Pb, Ba and In contamination associated with the process. The residual contamination in each inner core slice from the procedure amounted to 0.2 ± 0.2 pg Pb with [superscript]206Pb/[superscript]207Pb, [superscript]208Pb/[superscript]207Pb and [superscript]206Pb/[superscript]204Pb ratios of 1.16 ± 0.12, 2.35 ± 0.16 and 15.3 ± 6.7 respectively, 1.5 ± 0.4 pg Ba and 0.6 ± 2.0 fg In. This technique was then utilised to obtain high resolution analyses of Pb, Ba and In concentrations, and Pb isotopes in ice core sections recovered from Law Dome, East Antarctica and from the East Rongbuk Glacier on the northern slope of Mount Everest in the Himalaya.Law Dome, East Antarctic Holocene ice cores provide strong evidence for the transport of anthropogenic Pb from Australia to the Law Dome environment during the late 19th century, with [superscript]206Pb/[superscript]207Pb and [superscript]208Pb/[superscript]207Pb ratios as low as 1.061 ± 0.001 and 2.339 ± 0.002 respectively, in close agreement with the Pb isotopic characteristics of Australian Broken Hill Pb ores. The onset of anthropogenic pollution of the Law Dome environment occurred in spring 1889 AD, associated with the onset of Pb ore smelting activities in Port Pirie, South Australia. Seasonal variability is most clearly seen in anthropogenic Pb and Ba (as a proxy for mineral dust) concentrations where peaks in concentrations generally occur in the autumn and spring periods, with consistently low concentrations during winter. Lead isotopic [superscript]206Pb/[superscript]207Pb ratios are inversely correlated with residual (anthropogenic + crustal) Pb concentrations with the lowest ratios occurring during periods of high Pb concentrations. The observed seasonal variability is associated with the annual cycle in position and strength of the Antarctic Circumpolar Trough, a region of low pressure situated off the coast of Antarctica, which moves closest to the Antarctic coast and increases in strength during the autumn and spring seasons. Concurrently, a strengthening of the Southern Ocean westerlies entrains and transports more atmospheric impurities from continental regions such as Australia. The low Pb concentrations and relatively more radiogenic [superscript]206Pb/[superscript]207Pb ratios that appear in the winter layers are indicators of aerosol inputs into the Law Dome environment from a well mixed Southern Hemisphere atmospheric background.Law Dome deep ice core sections, sampled at short-term resolution, show variability in all measured species over time indicating a general instability in temperature (as indicated by δ18O compositions) and environmental conditions (as indicated by elemental concentrations) prevailing during the periods of time integrated by the ice. Based on Pb isotopic [superscript]206Pb/[superscript]207Pb ratios, which reach values of 1.225 ± 0.004 and 1.230 ± 0.003 in glacial, and last glacial – Holocene transition ice respectively, noticeable volcanic Pb contributions are found to occur in both time periods, reaching as high as ~39% and ~46% respectively. These increases are associated with a decrease in mineral dust concentrations due to relatively warmer climatic conditions prevailing within the times integrated by the ice core sections. A link between temperature and environmental conditions in glacial ice is observed when changes in δ18O compositions (as a proxy for temperature) exceed 0.24‰. In contrast, there is no link between temperature and environmental conditions during the last glacial – Holocene transition period, demonstrating a complicated climatic and environmental state existing at Law Dome at this time that incorporates aspects of both cold and warm climates.The high spatial resolution sectioning of continental glacial ice cores recovered from the East Rongbuk Glacier on the northern slopes of Mount Everest, and dated to the 18th and 20th centuries, has similarly shown variability in all measured species over time. Elemental Pb, Ba and In concentrations are very well correlated in all ice core sections confirming the environment of the East Rongbuk Glacier, within the investigated time periods, to be strongly controlled by the input of mineral dust. Isotopic [superscript]206Pb/[superscript]207Pb ratios in 18th century ice range from 1.18 – 1.21 which are attributed to a natural mineral dust background devoid of any influences of anthropogenic [or volcanic] activity. During 18th century monsoon periods (when mineral dust concentrations are generally low), local Himalayan material plays an important role on crustal inputs into the sampling region, with some inputs of Indian derived material possibly sourced to the Indian Peninsula, and Trans-Himalayan belt/Lhasa block material sourced to locations slightly north of Mount Everest. During non-monsoon periods (when mineral dust concentrations are generally high), it is likely that mineral dust from regions in northern Africa and central Asia are impacting on the high altitude Himalaya, with some possible contributions from the arid regions in north-western India and local Himalayan material.Based on elemental (Pb/Ba) and Pb isotopic ratios, there is no indication ofanthropogenic [or volcanic] Pb contributions in the 20th century East RongbukGlacier ice core samples indicating that, prior to 1952 AD, the high altitude samplingsite was isolated from the effects of anthropogenic Pb pollution. Consequently, inthe 20th century, Pb transported to the East Rongbuk Glacier site is sourced tomineral dust. An increase in elemental concentrations is observed in 20th century ice,indicating increased mineral dust deposition relative to the 18th century.Concurrently, a marked change in the isotopic characteristics of 20th century ice coredata, relative to 18th century ice core data, is observed, with a clear segregation ofmonsoon and non-monsoon data and the transition of 20th century data to lessradiogenic values. This adjustment likely reflects environmental changes that haveoccurred from the 18th to the 20th centuries.
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Delfim, Ricardo. "Estudo espaço-temporal da variação dos parâmetros físicos e químicos no transecto 30ºS do Oceano Atlântico Sul." Universidade de São Paulo, 2012. http://www.teses.usp.br/teses/disponiveis/21/21133/tde-27032013-140708/.
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Na década de 90 surge a primeira tentativa de gerar dados capazes de legitimar um modelo climático mundial detalhado: O Experimento de Circulação Oceânica Global (World Ocean Circulation Experiment - WOCE) Dentro dos diversos subprogramas inseridos no WOCE destaca-se o programa Hidrográfico (WHP). A JAMSTEC (Japan Marine Science and Tecnology Center), após cerca de uma década volta a reocupar algumas estações do WHP-WOCE, com o programa BEAGLE (Blue Earth Global Expedition), tendo como proposta detectar e quantificar alterações correspondentes ao aquecimento global. A I Comissão Oceanográfica Trans-Atlântica (TAI 2009) também constituiu um projeto de reocupação da seção A10, linha central do Oceano Atlântico Sul (~30?S), previamente amostrada pelo WHP-WOCE e BEAGLE, tendo como objetivo identificar alterações espaciais e temporais dos parâmetros oceanográficos nas últimas duas décadas. Considerando os valores de temperatura e salinidade foi evidenciada a presença de pelo menos, cinco massas d\'água: i) Água Tropical de Superfície (ATS) acima da isopícnal ?0= 26,70 ii) Água Central do Atlântico Sul (ACAS) abaixo da isopícnal ?1= 27,05 iii) Água Intermediária Antártica (AIA) abaixo da isopícnal ?2= 27,20 (iv) Água Profunda do Atlântico Norte (APAN) abaixo da isopícnal ?3= 27,70 v) Água Antártica de Fundo (AAF). Nas camadas superficiais dos três programas, notou-se uma proporcionalidade inversa entre as concentrações de nutrientes e oxigênio dissolvido. O Programa TAI ao longo de todo o transecto A10, apresentou as menores concentrações de nutrientes abaixo dos 1000 dbar. O WHP-WOCE foi mais aquecido que os outros programas nas camadas superficiais. Nas profundidades acima da termoclina (~1000 dbar), na bacia leste o Programa BEAGLE apresentou diferenciações que sugerem uma atividade mais intensa de ressurgência, para seu ano de amostragem do que nos anos dos Programas WHP-WOCE e TAI. Porém baseado nos resultados do Programa TAI, na extremidade leste da Bacia do Atlântico Sul, pode-se inferir que há afloramento da Água Central do Atlântico Sul (ACAS), provinda de aproximadamente 900 dbar de profundidade, sobre a Plataforma Continental Sul Africana.<br>In the 90s comes the first attempt of generate data able to legitimize a comprehensive global climate model: The Wolrd Ocean Circulation Experiment (WOCE). Within various subprograms inserted into the WOCE, highlight the WOCE Hydrographic Program (WHP). The JAMSTEC (Japan Marine Science and Technology Center), after about a decade back to reoccupy some stations of WOCE-WHP, with a program called BEAGLE (Blue Earth Global Expedition), proposing to detect and quantify changes related to global warming. The 1st Trans-Atlantic Oceanographic Commission (TAI 2009) was also created as a project of A10 section reoccupation, aiming to identify spatial and temporal changes in oceanographic parameters after two decades WOCE-WHP and BEAGLE sampling. The A10 section, represents the axis of South Atlantic Ocean (~ 30?S). Considering the values of temperature and salinity the presence of at least five water masses can be inferred: i) Surface Tropical Water (ATS) above isopícnal ?0 = 26.70, ii) South Atlantic Central Water (ACAS) below the isopícnal ?1 = 27.05 iii) Antarctic Intermediate Water (AIA) below the isopícnal ?2 = 27.20, (iv) North Atlantic Deep Water (APAN) below the isopícnal ?3 = 27.70, v) Antarctic Bottom Water (AAF). On the superficial layers of the three programs, it was noted an inverse proportionality between the concentrations of nutrients and dissolved oxygen. The TAI program, throughout the A10 transect, showed the lowest concentrations of nutrients below 1000 dbar. The warmer in the superficial layers was WOCE-WHP. On the layers above the thermocline (~ 1000 dbar), the BEAGLE Program around East Basin, showed some anomalies that suggest its sampling happened during some more intense upwelling activity, for its year than in years of WHP- WOCE and TAI programs. But based on the results of the TAI Program, at the east end of the South Atlantic Basin, it\'s possible to infer that there is upwelling of South Atlantic Central Water (ACAS), coming from about 900 dbar depth on the South African continental shelf.
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Pourrier, Jonathan. "Caractérisation des processus de transferts et d’interactions entre les compartiments hydrologiques, hydrogéologiques et cryosphériques d’un bassin versant andin semi-aride soumis à une forte variabilité climatique (Vallée de l’Elqui – Chili)." Thesis, Montpellier 2, 2014. http://www.theses.fr/2014MON20108/document.
Texte intégralRésumé :
Le nord du Chili est soumis à un contexte climatique aride à semi-aride présentant une variabilité saisonnière et inter-annuelle forte. Dans cette région les zones de haute altitude soutiennent les parties plus basses des bassins versants, mais la ressource en eau reste malgré tout limitée. Afin d'améliorer les méthodes de gestion de l'eau dans ces bassins versants, il est important de préciser le rôle des zones de haute altitude dans le soutien des parties basses, mais aussi de caractériser les modalités de transfert et d'interaction entre les compartiments constitutifs de l'hydrosystème. Ce travail porte sur la caractérisation du fonctionnement hydrologique du bassin versant de l'Elqui depuis la tête de bassin, située au cœur de la cordillère des Andes, jusqu'aux vallées de la zone inférieure situées entre 500 et 2000 mètres d'altitude. En tête de bassin, les processus d'interaction entre les compartiments cryosphériques, hydrologiques et hydrogéologiques, et leurs impacts sur le transfert des masses d'eau vers l'aval de la zone d'étude sont caractérisés. Le comportement hydrologique des sous bassins versant partiellement ou non‑englacés est également étudié. Dans la zone inférieure du bassin, l'étude porte principalement sur les processus d'interactions surface-souterrain en contexte semi‑aride et sur les impacts des forçages climatiques et anthropiques sur ces derniers. Cette étude s'appuie sur plus de 40 ans de données hydro-météorologiques disponibles sur la zone inférieure du bassin, complétés par des mesures hydrologiques sur la zone supérieure (> 2000 mètres d'altitude) et des prélèvements chimiques (majeurs et traces) et isotopiques (²D, 18O) sur la totalité de la zone d'étude, réalisés entre 2011 et 2013.Ces travaux ont montré que le modèle conceptuel de fonctionnement du bassin versant de l'Elqui généralement accepté était incomplet. Dans la zone supérieure, l'étude d'un bassin versant englacé a permis de montrer que le rôle de la cryosphère dépasse la fonction de production d'eau, avec certains compartiments stockant temporairement de l'eau en période humide et la libérant en période sèche. Ce processus permet d'amortir la variabilité temporelle des précipitations et du taux de fonte en altitude. Les analyses physico-chimiques réalisées dans le bassin versant ont également permis d'identifier des compartiments aquifères ignorés jusqu'à maintenant, comme les compartiments volcanique et plutonique. En améliorant les connaissances sur les processus d'interactions entre compartiments cryosphériques, hydrologiques et hydrogéologiques, les résultats de ce travail ont apporté des précisions sur le fonctionnement hydrologique de la zone de haute altitude. Cela a permis l'estimation des impacts potentiels de la variabilité climatique sur ces processus d'interactions et leurs conséquences sur la disponibilité et la qualité de la ressource. Dans la zone inférieure, la caractérisation des interactions surface-souterrain a montré qu'il existe un fort potentiel d'interaction entre le compartiment hydrologique et le compartiment alluvial, mais également entre le compartiment alluvial et le socle plutonique. L'étude des données hydrologiques et physico-chimiques a permis de caractériser le type d'échanges se déroulant entre les compartiments. Dans certains secteurs le processus dominant est la recharge du compartiment alluvial par le compartiment hydrologique, tandis que pour d'autres il existe une alternance entre période de drainage du compartiment alluvial par le compartiment hydrologique et période de recharge du compartiment alluvial. La réponse de ces processus face aux impacts des forçages climatiques et anthropiques contraindra la disponibilité et la qualité de la ressource dans les années à venir. Ainsi, les résultats apportés par ce travail permettront certainement de mieux anticiper les modifications futures du fonctionnement hydrologique des bassins versant montagneux en contexte semi-arides<br>The north Chile is affected by an arid to semi-arid climate, associated with a strong seasonal to inter-annual variability. In this region, while mountainous areas are supporting low areas, the availability of water resources remains limited. In order to improve the water management in these basins, it is necessary to precise how the high areas support the low areas, and to characterize water transfers and interaction processes between the constitutive compartments of the hydrosystem. This work concern the characterization of the hydrodynamic behavior of the Elqui watershed from the headwaters, in the Andes, to the valleys, ranging between 500 and 2000 m.a.s.l.In the headwaters, the interactions processes between cryospheric and hydrologic compartments and their impact on water transfers to the low areas are characterized. The behavior of unglacierized or partially glacierized watershed is also studied. In the low area of the watershed, the study mainly considers groundwater-surface water interactions under semi-arid context and the impact of the climatic variability on these processes. This study is based on more than 40 years of hydro-meteorological data available in the lower zone of the basin, completed by hydrological measurements in the upper zone (> 2000 m.a.s.l.) and chemical (majors and traces elements) and isotopic samples (²D, 18O) over the whole study area realized between 2011 and 2013.This work demonstrated that the conceptual model of the Elqui basin hydrological behavior, generally accepted, was incomplete. In the high area (> 2000 m.a.s.l.), the study of a glacierized watershed show that the function of the cryosphere overpass the water production with some compartments storing water during humid periods and draining their water content during dry periods. This process buffers the temporal variability of precipitations and melting rates in the high area. Physico-chemical analysis, allows to identify some ignored aquifer compartments, as the volcanic and plutonic compartments. The results of this study improve the knowledge about interactions processes between cryospheric, hydrologic and hydrogeologic compartments, which precise the hydrological functioning of the high area. The interpretation of the hydrological behavior of the high altitude area allows to better understand the way that it support the low area, and the way that climate variability may affects it.In the low area, results show that the groundwater-surface water interaction potential is good between alluvial and hydrological compartments, but also between the plutonic and the alluvial compartments. The study of hydro-meteorological and physico-chemical data allowed to characterize the type of exchanges that take place between groundwater and surface water. In some sectors the main process is the recharge of the alluvial compartment by the hydrological compartment, while in other sectors the processes show a seasonal variability with periods of alluvial compartment recharge and periods of hydrological compartment support. The answer of these processes face to climatic and anthropic forcing will constrain the evolution of the availability and quality of the water resources in the Elqui basin. Finally, the results of this study will certainly allow to better anticipate the future modifications of the semi-arid mountainous watershed hydrological functioning
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Capell, René. "Modelling dominant runoff processes using tracers and landscape organisation in larger catchments." Thesis, University of Aberdeen, 2011. http://digitool.abdn.ac.uk:80/webclient/DeliveryManager?pid=186120.
Texte intégralRésumé :
This work has contributed to the understanding of dominant runoff generation at the large catchment scale and to the understanding of the relationships between landscape properties and hydrological behaviour. The developed models were used to estimate the climate change impact on the hydrology in the study catchment. A multivariate geochemical tracer survey was carried out in North Esk catchment in north east Scotland. A generic typology was developed using multivariate statistical methods to characterise the hydrochemical tracer response. Upland headwater runoff was dominant downstream in winter and provided significant flows during base flow periods in summer. These insights were complemented by a conjunctive analysis of long-term river flow data and a one year stable isotope survey. Integrative metrics of transit times, hydrometric responses, and catchment characteristics were explored for relationships at the large catchment scale. The evaluation that the associated soils and bedrocks, themselves controlling the flow path distribution, have a strong influence on the integrated hydrological catchment response. The empirically-based understanding of dominant runoff generation processes in the North Esk uplands and lowlands were used in a stepwise rainfall-runoff model development. Tracers were directly incorporated to reduce structural and parameter uncertainty. The integration of tracers helped reduce parameter uncertainty. These tracer-aided models increased confidence for using them to explore the effects of environmental change. Climate change impacts in the catchment where explored by forcing the models with projected climate change forcing from the UK Climate Projections 2009. The results revealed landscape-specific changes in the hydrological response with increased summer drought risk in the lowlands and diminishing snow influence and increased winter floods in the uplands. The spatial integration mediated the extremes observed in the subcatchments.
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Armandine, Les Landes Antoine. "Impact des variations climatiques sur les ressources hydrogéologiques." Thesis, Rennes 1, 2014. http://www.theses.fr/2014REN1S101/document.
Texte intégralRésumé :
Les eaux souterraines représentent environ 98% des eaux douces potentiellement disponibles pour l'homme sur notre planète, en faisant donc une ressource fondamentale de nos sociétés. Du fait du changement climatique et du fort lien existant entre le climat et le cycle de l'eau, une préoccupation légitime est née concernant l'impact potentiel de ce changement climatique sur les ressources en eau. À ce jour, des évidences de plus en plus nombreuses appuient le fait que les modifications des conditions climatiques se répercutent sur le cycle hydrologique. L'identification de la sensibilité des eaux souterraines aux variations climatiques est donc devenue indispensable. Or, le climat est un système hautement complexe dont les variations, contrôlées par de nombreux facteurs à la fois naturels et anthropiques s'effectuent sur toutes les échelles de temps. Les modifications climatiques ne sont donc pas un phénomène nouveau, les eaux souterraines ont par conséquent subi dans le passé les effets de ces variations climatiques, elles en subissent actuellement les changements et subiront celles à venir. Les travaux développés dans cette thèse ont abordé cette problématique visant à caractériser la sensibilité de la ressource en souterraine face aux variations climatiques. À l'aide de l'analyse de traceurs environnementaux à l'échelle régionale, les impacts d'évènements climatiques majeurs intervenus sur les derniers millions d'années (transgression marine et période glaciaire) sont mis en évidence au sein du système hydrogéologique actuel. Puis, à l'aide de modélisation hydrogéologique, l'impact du changement climatique est étudié à travers les relations particulières existantes entre l'eau souterraine et les compartiments de surface et l'océan. Toutes ces études mettent en avant la sensibilité de la ressource en eau souterraine aux variations climatiques en termes de qualité (salinisation) et de quantité (baisse des niveaux d'eau). Les ressources hydrogéologiques sont particulièrement sensibles aux variations climatiques et hydrologiques (modifications de recharge, intrusions eau de mer…) ainsi qu'aux facteurs non climatiques (activités humaines). La gestion de cette ressource nécessite donc de considérer à la fois les risques climatiques et non climatiques ainsi que de prendre en compte l'adaptation à long terme de ces systèmes<br>Groundwater resources represent approximately 98% of global freshwater resources available for humans on our planet; therefore groundwater is fundamental resource of our societies. Due to climate change and strong link between climate and the cycle of water, an understandable concern is appeared about the potential impacts of climate change on water resources. Nowadays, growing body of evidence supports the fact that changes in climatic conditions (temperature, precipitation, evaporation…) impact the hydrologic cycle and consequently groundwater resources. The identification of groundwater sensibility to climate variations has become essential. The climate is a highly complex system where its variations drive by many factors both natural and human occurs on all time scales. Climatic changes are not a new phenomenon, groundwater resources have already been impacted by effects of climatic variations, are impacting presently and will be in the future. The work carried out under this thesis covered this problematic to characterize the groundwater resources sensibility to climate variations. With the help of environmental tracers analyzed at the regional scale, impacts of major climate events occurred since the last millions years (marine transgression and glacial period) have been identified in the current hydrogeologic system. Then, support by hydrogeological modeling the impact of climate change has been studied through the specific relationships between groundwater and surface water bodies and ocean. All these studies highlight the important sensibility of groundwater resources to climate variations in terms of quality (salinization) and quantity (lower water levels). Hydrogeological resources are particularly sensitive to climate and hydrological variations (recharge changes, seawater intrusion…), as well as to non-climatic factors (human activities). Thus groundwater resources management needs to consider both climatic and non-climatic risks and the long-term adaptation of these systems
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Ternois, Yann. "Contribution des traceurs organiques a l'etude des paleo-climats." Paris 6, 1996. http://www.theses.fr/1996PA066409.
Texte intégralRésumé :
Depuis le debut des annees 1980, l'etude des cetones a longue-chaine (clc) suscite l'interet croissant des paleo-climatologues. Leurs rapports d'insaturation, lies aux temperatures des eaux de l'ocean de surface, sont conserves dans les sediments profonds et peuvent etre utilises comme paleo-proxis de temperatures. Nous avons, dans la premiere partie de ce travail, etudie le cycle de production des clc sur l'ocean actuel. Apres avoir mis au point un protocole experimental afin d'optimiser l'analyse chromatographique de ces molecules, nous avons etalonne le rapport u#k#'#3#7 des eaux de surface de la mediterranee nord occidentale. A partir de l'analyse de pieges a particules et de sediments superficiels, nous avons etudie, dans ce bassin, le cycle de production des coccolithophorides et le transfert du signal u#5#'#3#7 vers l'ocean profond. Nos resultats ont montre que le developpement de ces algues se produisait a deux epoques differentes de l'annee en mediterranee occidentale et orientale. Dans la deuxieme partie de cette these, nous avons mene une etude de plusieurs traceurs moleculaires dans les sediments superificiels et de deux carottes de la marge nord-africaine. Nous avons localise les zones actuelles d'upwellings a partir du rapport u#k#'#3#7, du contenu en clc, et en corg des sediments de surface. L'analyse en haute resolution temporelle des clc, des sterols, et des alcools gras, a permis de caracteriser la variabilite climatique des depots organiques au sud et au nord de la zone. L'evolution des temperatures de surface, des apports autochtones et allochtones au cours des derniers 150 000 ans, montre que ce sont les forcages haute latitude qui ont influence le nord de la zone, alors qu'au contraire les forcages basse latitude ont plus fortement marque la region du cap blanc, au sud
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Marques, Alessandra Abe Pacini Schmidt. "The role of hydrogen and beryllium isotopes as tracers of solar and climate variability." Instituto Nacional de Pesquisas Espaciais, 2010. http://urlib.net/sid.inpe.br/mtc-m19/2010/09.10.18.49.
Texte intégralRésumé :
A história do clima terrestre e sua relação com a atividade solar podem ser reconstruídas a partir de informações encontradas em registros naturais. Dentre esses registros, os isótopos estáveis do hidrogênio e os radioisótopos cosmogênicos do berílio são usualmente analisados, retirados de diferentes matrizes naturais, especialmente de testemunhos de gelo e amostras de ar. Nesta tese, a razão deutério/hidrogênio, extraída de testemunhos de gelo, e a atividade do $^7$Be, medida em amostras de ar, foram utilizadas para o estudo do papel de diferentes fenômenos climáticos e solares em suas variações. Os dados de deutério foram obtidos a partir de testemunhos de gelos das regiões polares (Groenlândia e Antártica) e equatoriais (Andes) para as últimas quatro décadas (1951 1994). Foi encontrada uma periodicidade decadal nessas séries isotópicas, que parece ser o resultado de uma influência direta da modulação da irradiância solar no ciclo hidrológico global. Além disso, os resultados encontrados enfatizaram a importância dos regimes climáticos locais na variabilidade do deutério medido. Os dados de berílio-7 foram extraídos de amostras de ar coletadas próximas ao solo desde 1987 (com resolução temporal trimestral) nas cercanias da Usina Nuclear de Angra, no Rio de Janeiro, Brasil, e também de amostras de ar coletadas e medidas (semanalmente) pela nossa própria instrumentação instalada desde o final de 2008 no campus da Universidade Estadual do Rio de Janeiro. Dados e modelos numéricos da Universidade de Oulu, Finlândia, foram também utilizados na análise das origens da variabilidade do $^7$Be. Os resultados indicam que o forçante dominante da modulação dos dados de 7Be do Rio de Janeiro é o padrão regional de chuvas, tornando as variações locais da produção cosmogênica (causada por raios-cósmicos) não evidentes nos dados. Além disso, nossos resultados indicaram que eventos anômalos da dinâmica troposférica podem imprimir nos dados de $^7$Be as informações dos movimentos 3-D das massas de ar. Assim, essa tese explora as informações contidas nas séries temporais dos isótopos estudados, mostrando os potenciais usos científicos de cada um deles e destacando a necessidade de interpretações mais cuidadosas das modulações isotópicas utilizadas como traçadores de variações climáticas e solares.<br>The history of Earth's climate and the role of solar activity as a driver of the observed changes can be recovered through the study of natural records. Among them, stable isotopes of hydrogen and cosmogenic radioisotopes of beryllium are usually analyzed, especially from ice cores and air samples. In this thesis, deuterium/hydrogen ratio from ice cores and $^7$Be activity from air samples are analyzed to study the role of different climatic and solar phenomena in their variation. Deuterium isotope data were obtained from polar (Greenland, Antarctic) and equatorial (Andes) regions for the last four decades (1951-1994). It has been found that deuterium series present a decadal cycle, which might be a direct influence of solar irradiance modulation on the hydrological cycle. Furthermore, the results emphasize the importance of the local climatic system on the deuterium isotopic temporal variability. Berylium-7 data were obtained from near-ground air samples measured since 1987 around the Angras Nuclear Power Station (with 3-month time resolution) , in Rio de Janeiro, Brazil, and also from air-samples acquired by our own instrumentation installed in the campus of University of Rio de Janeiro State since late 2008 (with weekly time resolution). Data and model results from Oulu University, Finland, were also used in the $^7$Be variability study. For the Brazilian isotopic data, the dominant driver of its modulation was found to be the regional precipitation pattern, with the local production by cosmic-rays having a minor effect on its variability. Moreover, our results indicate that anomalous events of tropospheric dynamics may also imprint information about air masses 3-D movement in the near-ground air $^7$Be data. Thus, this thesis explores the information contained in the studied isotopic time series, showing the potential scientific uses of them and highlighting the necessity of more careful interpretations of the isotopic modulation as proxies of climatic and solar variations.
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Drösler, Matthias. "Trace gas exchange and climatic relevance of bog ecosystems, Southern Germany." [S.l.] : [s.n.], 2005. http://deposit.ddb.de/cgi-bin/dokserv?idn=977967735.
Texte intégralLivres sur le sujet "Climatic tracers"
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K, Swart P., ed. Climate change in continental isotopic records. American Geophysical Union, 1993.
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1955-, Dawson Todd E., and Siegwolf Rolf T. W, eds. Stable isotopes as indicators of ecological change. Elsevier Academic Press, 2007.
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National Climatic Data Center (U.S.) and United States. Naval Meteorology and Oceanography Command. Fleet Numerical Meteorology and Oceanography Detachment., eds. Global tropical/extratropical cyclone climatic atlas. 2nd ed. The Command, 1996.
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Piper, David Z. Trace-element deposition in the Cariaco Basin, Venezuela shelf, under sulfate-reducing conditions: A history of the local hydrography and global climate, 20 ka to the present. U.S. Dept. of the Interior, U.S. Geological Survey, 2002.
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Piper, David Z. Trace-element deposition in the Cariaco Basin, Venezuela shelf, under sulfate-reducing conditions: A history of the local hydrography and global climate, 20 ka to the present. U.S. Dept. of the Interior, U.S. Geological Survey, 2002.
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Tze-shan, Cheng. A modified persistence-climatology method to forecast tropical cyclone movement. Royal Observatory, 1986.
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Piper, David Z. Trace-element deposition in the Cariaco Basin, Venezuela shelf, under sulfate-reducing conditions: A history of the local hydrography and global climate, 20 ka to the present. U.S. Dept. of the Interior, U.S. Geological Survey, 2002.
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Piper, David Z. Trace-element deposition in the Cariaco Basin, Venezuela shelf, under sulfate-reducing conditions: A history of the local hydrography and global climate, 20 ka to the present. U.S. Dept. of the Interior, U.S. Geological Survey, 2002.
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Piper, David Z. Trace-element deposition in the Cariaco Basin, Venezuela shelf, under sulfate-reducing conditions: A history of the local hydrography and global climate, 20 ka to the present. U.S. Dept. of the Interior, U.S. Geological Survey, 2002.
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Piper, David Z. Trace-element deposition in the Cariaco Basin, Venezuela shelf, under sulfate-reducing conditions: A history of the local hydrography and global climate, 20 ka to the present. U.S. Dept. of the Interior, U.S. Geological Survey, 2002.
Trouver le texte intégralChapitres de livres sur le sujet "Climatic tracers"
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Joussaume, S., and J. Jouzel. "Simulation of Paleoclimatic Tracers Using Atmospheric General Circulation Models." In Abrupt Climatic Change. Springer Netherlands, 1987. http://dx.doi.org/10.1007/978-94-009-3993-6_31.
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Maier-Reimer, Ernst, and Robert Bacastow. "Modelling of Geochemical Tracers in the Ocean." In Climate-Ocean Interaction. Springer Netherlands, 1990. http://dx.doi.org/10.1007/978-94-009-2093-4_13.
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Woyczyński, W. A. "Passive tracer transport in stochastic flows." In Stochastic Climate Models. Birkhäuser Basel, 2001. http://dx.doi.org/10.1007/978-3-0348-8287-3_18.
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Feichter, Johann, Erich Roeckner, Ulrich Schlese, and Martin Windelband. "Tracer Transport in the Hamburg Climate Model." In Air Pollution Modeling and Its Application VIII. Springer US, 1991. http://dx.doi.org/10.1007/978-1-4615-3720-5_44.
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Genthon, Christophe, Alexandre Armengaud, and Gerhard Krinner. "Climate and Atmospheric Tracers Modelling with GCM, Polar Applications." In Chemical Exchange Between the Atmosphere and Polar Snow. Springer Berlin Heidelberg, 1996. http://dx.doi.org/10.1007/978-3-642-61171-1_26.
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Medved, Sašo. "Urban Environment and Local Climate." In Springer Tracts in Civil Engineering. Springer International Publishing, 2021. http://dx.doi.org/10.1007/978-3-030-74390-1_7.
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Maier-Reimer, Ernst. "Design of a 3D Biogeochemical Tracer Model for the Ocean." In Modelling Oceanic Climate Interactions. Springer Berlin Heidelberg, 1993. http://dx.doi.org/10.1007/978-3-642-84975-6_12.
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Nakamura, Hisashi, Takeaki Sampe, Youichi Tanimoto, and Akihiko Shimpo. "Observed Associations Among Storm Tracks, Jet Streams and Midlatitude Oceanic Fronts." In Earth's Climate. American Geophysical Union, 2013. http://dx.doi.org/10.1029/147gm18.
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Kiehl, J. T. "The Climatic Effects of Ozone and Trace Gases." In Atmospheric Ozone. Springer Netherlands, 1985. http://dx.doi.org/10.1007/978-94-009-5313-0_21.
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Whitfield, Michael. "Ocean Biology, Trace Metals and Climate." In Modelling Oceanic Climate Interactions. Springer Berlin Heidelberg, 1993. http://dx.doi.org/10.1007/978-3-642-84975-6_10.
Texte intégralActes de conférences sur le sujet "Climatic tracers"
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Ferrier, Bernard, Roberto Olivari, Francesco Greco, and Gabriele Librandi. "Deployment Methodologies of Fleet Air Vehicles on New Small Air Capable Ships." In Vertical Flight Society 80th Annual Forum & Technology Display. The Vertical Flight Society, 2024. http://dx.doi.org/10.4050/f-0080-2024-1056.
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Launch, recovery, and deck handling operations are among the most challenging tasks in the deployment of fleet piloted and unpiloted air vehicles on board of air capable ships. In today's long-lead acquisition process, some existing devices are installed on new ship platforms for which the air vehicle was not initially designed. As part of the Navy deployment process, a ship suitability assessment is conducted in the form of Dynamic Interface (DI) testing. DI testing evaluates all aspects of shipboard helicopter including suitability, compatibility, adequacy, effectiveness, safety of air vehicle shipboard Flying Qualities and Performance (FQ&P), aviation support facilities and procedures for all ship-based aircraft types. With monohulled rudder/screws steered legacy vessels, certain seakeeping and turbulent boundary properties have open-ocean performance similarities. When faced with a deployment target ship producing different ship properties, a systematic approach to adapt to the new environmental condition is devised. A significant example involves the deployment of air vehicles (both piloted and unpiloted) on-board LCS class vessels where large, unexpected roll oscillations, coupling with rapid motions of the stern, are recorded. These unusual deck responses have been traced to shipboard operational characteristics which do not relate to the seaway alone. The implications for air vehicle operations encountering seemingly random large motions further underscores the need for an accurate definition of the ship's dynamics and, possibly, refined models able to predict steep motions anticipating the onset of excessive movements. In this paper we describe a new instrumentation with the goal to predict ship motions conditions with sufficient forecasted time (over a minute) to launch, recover and complete other motion sensitive tasks regardless of the seaway. The fundamental concept is to measure remote sea surface profiles to predict the future wave forces acting upon a vessel as a function of the approaching air vehicle. The final objective is to expand ship operating deck limits to approximately Sea State 6+. This will allow the air's vehicle operator to have a more complete deck information and ship behavior. This article describes the common test procedures being developed at Fincantieri to define the deck behavior with the least air vehicle modifications. Enhanced dynamic interface testing is designed to better understand how the new ship classes affect the deck environment. The enhanced trial methodology test results clearly characterize essential aspects of the ship responses to the maritime climate and its impacts on air vehicle launch and recovery.
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Joussaume, S., and R. Sadourny. "Simulation of the atmospheric cycle of desert dust particles using a general circulation model." In Coherent Laser Radar. Optica Publishing Group, 1987. http://dx.doi.org/10.1364/clr.1987.wa3.
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Aerosol particles are interesting from many viewpoints - e.g. pollutant impact on ecosystems, climatic impact on the hydrologic cycle and through radiative properties - and can also be a tool for satellite measurements. Atmospheric general circulation models having proved their capability to reproduce the main features of climate, can be appropriate tools to study the atmospheric cycles of aerosol particles. Such simulations cannot be done without a severe comparison with observations, but afterwards they can give an extensive 3-dimensional vision of the tracer cycles and be used for sensitivity or forecasting studies.
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Boumediene, Naima, Florence Collet, Sylvie Prétot, Lazhar Ayed, and Sami Elaoud. "Experimental and Numerical Study of Hygrothermal Behaviour of a Washing Fines Hemp Test Wall." In 4th International Conference on Bio-Based Building Materials. Trans Tech Publications Ltd, 2022. http://dx.doi.org/10.4028/www.scientific.net/cta.1.195.
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Bio-based materials are a promising tracks that offer thermal and environmental performances in order to reduce the consumption of energy and of non-renewable resources. For this purpose, in a previous study, the LGCGM worked on the development of Washing Fines Hemp composites (WFH) and characterized them on multiphysical points of view. Such materials show low thermal conductivity and high moisture buffer ability. In order to characterize their hygrothermal behavior at wall scale, a test wall is set up in an air-conditioned bi-climatic test room to simulate indoor and outdoor climates. This paper investigates the characterization of hygrothermal behavior of Washing Fines Hemp wall under typical Tunisian summer climate. It consists in an experimental study, supplemented by numerical simulation performed with WUFI Pro V6.5 software. The experimental hygrothermal response of the wall to such solicitations is analyzed from the temperature and relative humidity kinetics at several positions in the wall and from temperature and vapor pressure profiles. It shows that for daily cycles the two thirds of the thickness of the wall on the exterior side are active, as well regarding heat and moisture phenomena. More sorption-desorption phenomena are highlighted. The numerical results are consistent with experimental data for temperature and underestimate vapor pressure in the inner part of the wall.
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Al-Ghazawi, Ziad, and William Blanford. "RIVER BANK FILTRATION FOR WASTEWATER REUSE IN IRRIGATION: ADAPTATION TO CLIMATE CHANGE." In 22nd SGEM International Multidisciplinary Scientific GeoConference 2022. STEF92 Technology, 2022. http://dx.doi.org/10.5593/sgem2022/4.1/s19.47.
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In the context of adaptation of the water resources sector to climate change, water reuse is widely proposed and encouraged especially in arid and semi-arid areas like the Middle East. We consider riverbank filtration (RBF) an appropriate technology that efficiently and dependably procure quality water from Zarqa River thus making a contribution to protect Jordan�s remaining surface and ground water resources. The river is contaminated with treated domestic and industrial wastewater principally from the city of Amman, but still serves as a main source for irrigation water. Since 2007, a riverbank filtration (RBF) well field consisting of six wells was installed along the Zarqa river, Jordan. Salt tracers were released to the hyporheic zone and were detected in a RBF well (5 m distance from the river) during subsequent pumping. From the tracer test data (pumping rate: 10 m3/h), rapid travel times were approximated (14 m/min). Additional sampling demonstrated that fecal indicator bacteria and bacteriophages were removed from river water by RBF at the Zarqa River field site by up to 4.2 log10, which is a significant improvement of the river water quality. This implies that public health risks from exposure to riverbank filtrated water, like consumption of raw vegetables that are irrigated with this water, may be reduced by 2000 to 2500 times as compared to using river water directly. These results suggest that riverbank filtration is an appropriate technology which can enhance the safe reuse of treated wastewater.
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Haskins, R. D., and L. D. Kaplan. "Remote Sensing of Trace Gases Using the Atmospheric InfraRed Sounder (AIRS) Part 1: Sensitivity Analysis." In Optical Remote Sensing of the Atmosphere. Optica Publishing Group, 1990. http://dx.doi.org/10.1364/orsa.1990.md9.
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The importance of monitoring the trace gases active in the thermal infrared region of the spectrum is becoming more and more critical in light of the recent results regarding climate change and the greenhouse effect. Sources and sinks of anthropogenic gases such as CO, CH4, and CFC’s are important parameters in determining the climatic impact of man’s use of the Earth’s resources. The Atmospheric InfraRed Sounder (AIRS)1 is a moderately high spectral resolution (ν/Δν = 1200) infrared sounder selected as facility instrument on the Earth Observing System (Eos). The primary purpose of AIRS is the extraction of atmospheric and surface temperature useful for weather prediction. However, AIRS complete infrared coverage from 17 to 3.3 microns will also allow the retrieval of many other useful weather and climate parameters such as the ability to monitor certain IR active trace gases. The moderate spectral resolution of AIRS does not permit the sensing of individual molecular lines so that interfering species must be accounted for and retrieved simultaneously. The results of sensitivity simulations in this study indicate that a number of useful measurements of column abundances of trace gases can be made.
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Tyrallová, Lucia. "Automated object detection of climate tracers in remote-sensing data." In SPIE Remote Sensing, edited by Christopher M. U. Neale and Antonino Maltese. SPIE, 2011. http://dx.doi.org/10.1117/12.898111.
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Trudel, Gisèle. "Ecotechnologies of Practice: in-forming changing climates." In 28th International Symposium on Electronic Art. Ecole des arts decoratifs - PSL, 2024. http://dx.doi.org/10.69564/isea2023-33-short-trudel-ecotechnologies-of-practice.
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SHORT PAPER. How do ecotechnologies of practice actualize? This paper traces the material/theoretical operations of an ongoing research-creation concerned with changing climates. It mixes information in experimental approaches from collectivities of trees, media arts and forest sciences. Through individuations of symbiotic modulations, the paper is a thinking-with Balsam Fir, Diana Beresford-Kroeger, Camera, Domingo Cisneros, Dendrometer, Erin Manning, Isabelle Stengers, Jack Pine, Gilbert Simondon, Light Emitting Diodes, Numbers, Microphone, Recorder, Sapflow, Sensings, Speakers, Sugar Maple, Temperature, Yellow Birch.
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Jakabová, Vanda, Mattias Lantz, Emma Nilsson, et al. "Radiocesium traces the impact of climate on erosion in Sweden." In Goldschmidt2023. European Association of Geochemistry, 2023. http://dx.doi.org/10.7185/gold2023.16678.
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Capell,, R., D. Tetzlaff, R. Essery, and C. Soulsby. "Climate change impacts on catchment hydrology – a tracer-aided model approach." In BHS 11th National Hydrology symposium. British Hydrological Society, 2012. http://dx.doi.org/10.7558/bhs.2012.ns10.
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Kim, Sookyung, Hyojin Kim, Joonseok Lee, et al. "Deep-Hurricane-Tracker: Tracking and Forecasting Extreme Climate Events." In 2019 IEEE Winter Conference on Applications of Computer Vision (WACV). IEEE, 2019. http://dx.doi.org/10.1109/wacv.2019.00192.
Texte intégralRapports d'organisations sur le sujet "Climatic tracers"
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Ko, M. K. W. Assessing the climatic effect of carbon dioxide and other trace gases using an interactive two-dimensional climate-chemistry model. Final report, December 1992--August 1996. Office of Scientific and Technical Information (OSTI), 1996. http://dx.doi.org/10.2172/656484.
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Tran, Minh, and Albert Salamanca. Advancing climate policy: harnessing Indigenous knowledge at the science-policy interface. Stockholm Environment Institute, 2023. http://dx.doi.org/10.51414/sei2023.029.
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This paper focuses on a case study of Indigenous Peoples’ experience in climate policy negotiations under the UN Framework Convention on Climate Change (UNFCCC), with the Paris Agreement as a key milestone. The authors traced the role and advocacy of Indigenous Peoples at the Conference of the Parties (COP) as well as key actors, priorities, challenges and lessons learned leading up to and after the Paris Agreement.
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Ko, M. K. W., G. I. Molnar, and Shun-Tai Zhou. Assessing the climatic effect of carbon dioxide and other trace gases using an interactive two-dimensional climate-chemistry model. Progress report, December 1, 1992--November 30, 1993. Office of Scientific and Technical Information (OSTI), 1993. http://dx.doi.org/10.2172/10103201.
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Perrault, Anne, and Stephen Leonard. The Green Climate Fund: Accomplishing a Paradigm Shift? Rights and Resources Initiative, 2017. http://dx.doi.org/10.53892/mkmz2578.
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The Green Climate Fund (GCF), established in 2010 at the 16th Conference of Parties (COP16) under the United Nations Framework Convention on Climate Change (UNFCCC), is now the world’s largest climate financing institution. It has a current investment portfolio of 43 approved projects totaling around US$2 billion, and has 48 Accredited Entities (AEs) to support implementation, including UN agencies, banks, NGOs, and private companies. Through its investments, the GCF aims to achieve a paradigm shift in developing countries, toward low-emissions development and climate resilience. GCF investments must indicate whether and how they could impact Indigenous Peoples, local communities, and women who are most at risk from the adverse effects of climate change (e.g. via environmental and social management plans). These goals, however, are currently being challenged by inadequacies in the Fund’s policies and frameworks. GCF safeguards fail to recognize the critical contributions of rural peoples to the maintenance of ecosystem services that are essential to international climate and development objectives, and to offer adequate protection for their land and resource rights. Drawing on international standards and GCF policy documents, this report traces the adequacy and implementation effectiveness of the Fund’s current institutional frameworks across a representative sample of approved projects. Noting critical gaps in nearly every aspect of the Fund’s operational modalities and project approval processes, the report calls on the GCF to take progressive steps to make Indigenous Peoples’ and local communities’ rights a key part of its climate actions going forward.
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Zhuang, Qianlai. Quantifying Climate Feedbacks from Abrupt Changes in High-Latitude Trace-Gas Emissions. Office of Scientific and Technical Information (OSTI), 2012. http://dx.doi.org/10.2172/1054888.
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Schlosser, Courtney Adam, Katey Walter-Anthony, Qianlai Zhuang, and Jerry Melillo. Quantifying Climate Feedbacks from Abrupt Changes in High-Latitude Trace-Gas Emissions. Office of Scientific and Technical Information (OSTI), 2013. http://dx.doi.org/10.2172/1076751.
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Schattman, Rachel, Vern Grubinger, Lisa McKaeg, and Katie Nelson. Whole Farm Water Use: A Survey of Vegetable Producers in New England States | 2018. USDA Northeast Climate Hub, 2018. http://dx.doi.org/10.32747/2018.6938606.ch.
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Produce safety and climate change are two overlapping risks that face vegetable producers in the
 northeastern United States. Because of recent public health outbreaks (and subsequent litigation) traced
 back to fresh produce, food safety hazard identification and risk mitigation has become the focus of
 significant regulatory changes in the United States (FDA 2015)
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Bourhrous, Amal, Shivan Fazil, and Dylan O’Driscoll. Post-conflict Reconstruction in the Nineveh Plains of Iraq: Agriculture, Cultural Practices and Social Cohesion. Stockholm International Peace Research Institute, 2022. http://dx.doi.org/10.55163/raep9560.
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The atrocities committed by the Islamic State (IS) between 2014 and 2017 left deep scars on the Nineveh Plains in northern Iraq. IS deliberately targeted ethnic and religious communities with the aim of erasing the traces of diversity, pluralism and coexistence that have long characterized the region. To prevent people from living as Assyrians, Chaldeans, Kaka’i, Shabaks, Syriacs, Turkmen and Yazidis, IS destroyed sites of cultural and religious significance to these communities and devastated their livelihoods, including their crop and livestock farming activities. Using a people-centered approach, this SIPRI Research Policy Paper stresses the need for a holistic approach to post-conflict reconstruction in the Nineveh Plains that not only focuses on rebuilding the physical environment and economic structures, but also pays adequate attention to restoring the ability of communities to engage in cultural and religious practices, and to mending social and intercommunity relations. The paper highlights the interconnectedness of physical environments, economic structures, cultural practices and social dynamics. It stresses the need to address the impacts of the IS occupation while taking into account other pressing challenges such as climate change and water scarcity.
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Wurl, Oliver. Biofilm-like habitat at the sea-surface: A mesocosm study, Cruise No. POS537, 14.09.2019 – 04.10.2019, Malaga (Spain) – Cartagena (Spain) - BIOFILM. University of Oldenburg, 2020. http://dx.doi.org/10.3289/cr_pos537.
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OceanRep OceanRep Startseite Kontakt Schnellsuche Einfache Suche Erweiterte Suche Blättern Autor Forschungsbereich Publikationsart Jahr Studiengang Neuzugänge Artikel – begutachtet Alle Über uns GEOMAR Bibliothek Open Access Policies Grundsätze Hilfe FAQs Statistik Impressum Biofilm-like habitat at the sea-surface: A mesocosm study, Cruise No. POS537, 14.09.2019 – 04.10.2019, Malaga (Spain) – Cartagena (Spain) - BIOFILM . Logged in as Heidi Düpow Einträge verwaltenManage recordsManage shelvesProfilGespeicherte SuchenBegutachtungAdminLogout - Tools Wurl, Oliver, Mustaffa, Nur Ili Hamizah, Robinson, Tiera-Brandy, Hoppe, Jennifer, Jaeger, Leonie, Striebel, Maren, Heinrichs, Anna-Lena, Hennings, Laura Margarethe, Goncalves, Rodrigo, Ruiz Gazulla, Carlota und Ferrera, Isabel (2020) Biofilm-like habitat at the sea-surface: A mesocosm study, Cruise No. POS537, 14.09.2019 – 04.10.2019, Malaga (Spain) – Cartagena (Spain) - BIOFILM . Open Access . POSEIDON Berichte . University of Oldenburg, Oldenburg, 35 pp. [img] Text Cruise_Reports_POS537_final.pdf - publizierte Version Available under License Creative Commons: Attribution 4.0. Download (2417Kb) | Vorschau Abstract Biofilm-like properties can form on sea surfaces, but an understanding of the underlying processes leading to the development of these biofilms is not available. We used approaches to study the development of biofilm-like properties at the sea surface, i.e. the number, abundance and diversity of bacterial communities and phytoplankton, the accumulation of gel-like particles and dissolved tracers. During the expedition POS537 we used newly developed and free drifting mesocosms and performed incubation experiments. With these approaches we aim to investigate the role of light and UV radiation as well as the microbes themselves, which lead to the formation of biofilms. With unique microbial interactions and photochemical reactions, sea surface biofilms could be biochemical reactors with significant implications for ocean and climate research, e.g. with respect to the marine carbon cycle, diversity of organisms and oceanatmosphere interactions.
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Barker, Amanda, Taylor Sullivan, W. Baxter, et al. Iron oxidation–reduction processes in warming permafrost soils and surface waters expose a seasonally rusting Arctic watershed. Engineer Research and Development Center (U.S.), 2024. http://dx.doi.org/10.21079/11681/48714.
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Landscape-scale changes from climate change in the Arctic affect the soil thermal regime and impact the depth to permafrost in vulnerable tundra watersheds. When top-down thaw of permafrost occurs, oxygen and porewaters infiltrate deeper in the soil column exposing fresh, previously frozen material and altering redox conditions. A gap remains in understanding how redox stratifications in thawing permafrost impact the geochemistry of watersheds in response to climate change and how investigations into redox may be scaled by coupling extensive geophysical mapping techniques. In this study, we collected soils and soil porewaters from three soil pits and surface water samples from an Arctic watershed on the North Slope of Alaska and analyzed for trace metals iron (Fe) and manganese (Mn) and Fe oxidation state using bulk and microscale techniques. We also used geophysical mapping and soil thermistors to measure active layer depths across the watershed to relate accelerating permafrost thaw to watershed geochemistry. Overall, evidence showed that Fe and Mn could be useful as geochemical indicators of permafrost thaw and release of Fe(II) from thawing permafrost and further oxidation to Fe(III) could translate to a higher degree of seasonal rusting coinciding with the warming and thawing of near surface-permafrost.