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61.
Arto Miettinen Nalan Ko? Ian R. Hall Fred Godtliebsen Dmitry Divine 《Climate Dynamics》2011,36(3-4):533-543
August Sea Surface Temperatures (aSSTs) based on fossil diatom assemblages are generated with 2?year average resolution from a 230-year-long sediment core (Rapid 21-12B), from the Reykjanes Ridge in the subpolar North Atlantic. The results indicate a warming trend of ~0.5°C of the surface waters at the Reykjanes Ridge for the last 230?years. Superimposed on this warming trend there is a multidecadal to decadal aSST variability of up to 1°C. The interval from the 1770s to the 1830s represents the coldest period, whereas ~1860?C1880 represents the warmest period during the last 230?years. The last 25?years is characterized by a warming trend showing strong decadal aSST variability with several warm years, but also the coldest years since the 1820s. The time of these cold years in the mid-1970s, -1980s and -1990s correspond with the documented great salinity anomalies (GSA) in the North Atlantic suggesting increased fluxes of cold, low-salinity waters from the Arctic during the last decades. The aSST record and the August North Atlantic Oscillation (aNAO) index show similar multidecadal-scale variability indicating a close coupling between the oceanic and atmospheric patterns. The aSST record shows a negative correlation with the aNAO indicating cold aSST during the positive aNAO trend and vice versa. Results suggest that the wind driven variation in volume fluxes of the North Atlantic surface waters could be the major mechanism behind the observed relationship. 相似文献
62.
In situ chemical oxidation involves the introduction of a chemical oxidant into the subsurface for the purpose of transforming groundwater contaminants into harmless by‐products. Owing to oxidant persistence, groundwater samples collected at hazardous waste sites may contain both the contaminant(s) and the oxidant in a “binary mixture.” Binary mixtures composed of sodium persulfate (2.5 g/L; 10.5 mM) and volatile organic compounds (VOCs) (benzene, toluene, m‐xylene, perchloroethylene, trichloroethylene) were analyzed to assess the impact on the quality of the sample. A significant decline (49 to 100%) in VOC concentrations was measured in binary mixtures using gas chromatography (GC) purge and trap, and GC mass spectroscopy headspace methods. Preservation of the binary mixture samples was achieved through the addition of ascorbic acid (99 to 100% VOC average recovery). High concentrations of ascorbic acid (42 to 420 mM) did not interfere in the measurement of the VOCs and did not negatively impact the analytical instruments. High concentrations of ascorbic acid favored the reaction between persulfate and ascorbic acid while limiting the reaction between persulfate and VOCs. If an oxidant is detected and the binary sample is not appropriately preserved, the quality of the sample is likely to be compromised. 相似文献
63.
The Stogovce landslide in SW Slovenia triggered during the September 2010 extreme rainfall event 总被引:4,自引:4,他引:0
Ana Petkov?ek Rok Fazarinc Marko Ko?evar Matej Ma?ek Bojan Majes Matja? Miko? 《Landslides》2011,8(4):499-506
From September 16 to September 20, 2010, a cold weather front went across Slovenia. A heavy 4-day rainfall totaling between
300 and 520 mm caused large floods and triggered numerous rainfall-induced landslides. The damage due to the floods and landslides
is estimated over 250 million Euros. One of the largest landslides covering the area of approximately 15 ha was triggered
on flysch bedrock, just below a limestone overthrust zone. The sliding material properties, the inclinations of the slope,
and the water catchment area indicate that the landslide may transform into a fast moving debris flow. The necessary protective
measures were taken to protect inhabitants and the infrastructure against the disaster. The Stogovce landslide is one of the
numerous rainfall-induced landslides that have occurred in Slovenia on flysch bedrock in the last 10 years. It proves that
landslide risk on flysch territory is increasing. Special program of monitoring and protective measures will have to be developed
in near future to protect densely populated areas against landslides as a consequence of weather extremes. 相似文献
64.
Mahmoud Rahmati-Ilkhchi Shah Wali Faryad František V. Holub Jan Košler Wolfgang Frank 《International Journal of Earth Sciences》2011,100(1):45-62
Metamorphic basement rocks, that are exposed beneath the very low-grade to unmetamorphosed Upper Jurassic-Eocene formations
north of the Torud fault zone within the Great Kavir Block, were investigated to elucidate the origin of their protoliths
and the pressure and temperature conditions of metamorphism. The basement, previously assumed as a pre-Cambrian metamorphic
complex, is mostly formed by amphibolite-facies orthogneisses (tonalite, granodiorite, and granite) with amphibolites and
small amounts of metasediment-micaschists. Major- and trace-element geochemistry in combination with U–Pb age dating of zircon
showed that the protoliths formed during Late Neoproterozoic continental arc magmatism that has also been identified in other
tectonic blocks of Central Iran. In addition to quartz, feldspar(s), micas in orthogneisses, and amphibole + plagioclase in
amphibolite, all rocks may contain garnet that shows prograde zoning. Kyanite was found only in some Al-rich amphibolite together
with gedrite. The PT conditions of the rocks, based on conventional geothermobarometry and the pseudosection method, show
a medium-pressure amphibolite-facies metamorphism. Ar–Ar age dating of muscovite reveals that this metamorphism occurred in
the Middle Jurassic (166 Ma) and related to the closure of the Neotethyan basin. 相似文献
65.
Cem Iyigun Murat Türkeş İnci Batmaz Ceylan Yozgatligil Vilda Purutçuoğlu Elçin Kartal Koç Muhammed Z. Öztürk 《Theoretical and Applied Climatology》2013,114(1-2):95-106
In this study, the hierarchical clustering technique, called Ward method, was applied for grouping common features of air temperature series, precipitation total and relative humidity series of 244 stations in Turkey. Results of clustering exhibited the impact of physical geographical features of Turkey, such as topography, orography, land–sea distribution and the high Anatolian peninsula on the geographical variability. Based on the monthly series of nine climatological observations recorded for the period of 1970–2010, 12 and 14 clusters of climate zones are determined. However, from the comparative analyses, it is decided that 14 clusters represent the climate of Turkey more realistically. These clusters are named as (1) Dry Summer Subtropical Semihumid Coastal Aegean Region; (2) Dry-Subhumid Mid-Western Anatolia Region; (3 and 4) Dry Summer Subtropical Humid Coastal Mediterranean region [(3) West coast Mediterranean and (4) Eastern Mediterranean sub-regions]; (5) Semihumid Eastern Marmara Transition Sub-region; (6) Dry Summer Subtropical Semihumid/Semiarid Continental Mediterranean region; (7) Semihumid Cold Continental Eastern Anatolia region; (8) Dry-subhumid/Semiarid Continental Central Anatolia Region; (9 and 10) Mid-latitude Humid Temperate Coastal Black Sea Region [(9) West Coast Black Sea and (10) East Coast Black Sea sub-regions]; (11) Semihumid Western Marmara Transition Sub-region; (12) Semihumid Continental Central to Eastern Anatolia Sub-region; (13) Rainy Summer Semihumid Cold Continental Northeastern Anatolia Sub-region; and (14) Semihumid Continental Mediterranean to Eastern Anatolia Transition Sub-region. We believe that this study can be considered as a reference for the other climate-related researches of Turkey, and can be useful for the detection of Turkish climate regions, which are obtained by a long-term time course dataset having many meteorological variables. 相似文献
66.
The number of known near-Earth asteroids (NEAs) has increased rapidly in recent years due to large surveys. This discovery process has to be followed by follow-up observations to obtain a sufficient number of precise astrometric data needed for an accurate orbit determination of newly discovered bodies.Accurate orbit determination requires observations from at least two oppositions. If asteroids are not found in the next apparition, different from the discovery apparition, then they can be considered lost. This is particularly embarrassing for NEAs. If data for different apparitions are not found in the course of precovery surveys or in other archive data, then it is necessary to prepare targeted observations of a particular NEA in the second convenient apparition. Therefore NEA recovery is a very important part of NEA follow-up.We discuss here methods, techniques, and results of planned recoveries at the Klet' Observatory using a 0.57-m telescope equipped with a CCD detector. The Klet' NEA recovery subprogram has brought 21 planned NEA recoveries since 1997, including seven NEAs belonging to the potentially hazardous asteroid category.We briefly mention the overall work on NEA recoveries provided by several NEO follow-up programs as well as the need for communication resources supporting astrometric observers. Finally we present here a planned extension of the Klet' NEA recovery subprogram to fainter objects by means of a new 1.06-m reflector. 相似文献
67.
Hüseyin Akay Müsteyde Baduna Koçyiğit A. Melih Yanmaz 《Arabian Journal of Geosciences》2018,11(11):282
In this study, Hydrologic Engineering Center-Hydrologic Modeling System is used to simulate hydrologic processes in a watershed in Western Black Sea Region that frequently experiences flooding. The region is mountainous with steep hill slopes and receives high precipitation throughout the year. There are three stream gauging stations in the basin whose data are available for calibration and validation of hydrologic parameters. Simulations are performed for different scenarios to investigate the effect of using multiple stream gauging stations’ data on catchment wide calibration and validation of hydrologic parameters. Furthermore, performance of using calibrated internal stream gauging stations’ flow data in the estimation of hydrologic parameters in an assumed neighboring ungauged basin was assessed. It is found that using data of multiple stream gauging stations for calibration and validation gives satisfactory results for direct runoff hydrograph but the peak discharge predictions are not improved. The study results suggest that using data of internal stream gauging stations enables improved understanding of internal dynamics and transport in the basin and better predicted direct runoff hydrograph for the assumed neighboring ungauged basin. 相似文献
68.
J. Klime? M. D. Rowberry J. Blah?t M. Briestensky F. Hartvich B. Ko??ák J. Rybá? J. Stemberk P. ?těpan?íková 《Landslides》2012,9(3):407-415
It is possible to monitor slow-moving landslides and assess landslide stabilisation measures over protracted periods using an optical–mechanical crack gauge called a TM-71. This technical note outlines the theoretical background to the gauge and illustrates its practical application through a number of case studies. These studies are drawn from a range of landslide types and stabilisation measures. In terms of monitoring slow-moving landslides, three studies of deep-seated deformations are presented. The Taukliman coastal landslide on the Black Sea Coast is characterised by vertical and horizontal displacements of up to 0.2?mm?year?1 and sudden earthquake-induced dilations of up to 6?mm. The Parohy ridge spreading landslide in the Malá Fatra Mountains is characterised by gravitationally induced vertical displacements of 0.7?mm?year?1. The slope deformation that formed Cyrilka Cave in the Beskydy Mountains is characterised by very slow sinistral strike–slip movements of 0.8?mm?year?1. In terms of assessing landslide stabilisation measures, two studies are presented from Orava Castle in Slovakia and Tetín in the Czech Republic. The data recorded at these sites demonstrate that the constructed stabilisation measures have successfully alleviated the potential landslide hazard in both localities. These case studies clearly demonstrate that the gauge represents an important tool with which to monitor slow-moving landslides and assess landslide stabilisation measures. It is able to provide a precise three-dimensional record of deformation, withstand harsh environmental conditions, and record reliable data over protracted periods. 相似文献
69.
This paper intends to assess Taiwan’s energy security situation under current and future development of global environment.
We construct a static computable general equilibrium model for Taiwan to fulfill our purpose. The model is benchmarked in
2006 and includes detailed specification of power generation technology and renewable energy producing sectors. It also distinguishes
sources of imported energy to reflect Taiwan’s current policy of diversifying sources of supply for energy. Simulations using
the model have been focused on both changes in energy price and quantity of energy supply under specific specifications of
the development of renewable energy technologies and CO2 emission reduction requirements. Our simulation results demonstrate that energy security and climate change mitigation interact
each other, and under a specific emission reduction target, the effect of exogenous energy shocks on the economy will be partially
absorbed by the internal adjustment mechanism of the economy. 相似文献
70.
This study investigates the major and trace element geochemistry of Bigadi borate deposits, the largest colemanite and ulexite deposits in the world. The known borate deposits of Turkiye were deposited in the lacustrine environment during Miocene when the volcanic activity occurred from Tertiary to Quaternary. All of the Turkish borate deposits are classified as volcanic related deposits. Boron ore deposits intercalated with claystone, mudstone, tufa and fine layered limestone show lens shape. Borate minerals formed in two zones. Tiilu and Acep-Simav open mines represented the lower and upper borate zones, respectively. Colemanite and ulexite are dominant minerals at all ore zones. The major elements of Bigadi borates contain Ca, Si, Mg, Al, Fe, S, Na, P and Mn at Tiilu, Ca, Na, Si, Mg, S, Al, P and Mn at Simav, and Ca, Na, Si, Mg, S, AI and Mn at Acep samples respectively. Except for Li, Mo, Sb, As, Sr and Se, concentrations of other trace elements are significantly lower than averages of earth crust and andesite at the three mines. With respect to averages of earth crust and andesite, Mo, Sr, As, Li and particularly Se are enriched significantly in the Bigadi. In examining depth-dependent variations of major and trace elements, four element groups at the Tiilu site and six element groups at the Simav and Acep sites were determined. Element abudances or element geochemical trends show differences at the Tülü, Simav and Acep mines. These differences can be explained by the diversity of physicochemical conditions in the deposition environment by the effect of differences at the recharge regime and source. 相似文献