Using the Twentieth Century Reanalysis to assess climate variability for the European wind industry     

Philip?E.?BettEmail author  Hazel?E.?Thornton  Robin?T.?Clark 《Theoretical and Applied Climatology》2017,127(1-2):61-80

We characterise the long-term variability of European near-surface wind speeds using 142 years of data from the Twentieth Century Reanalysis (20CR), and consider the potential of such long-baseline climate data sets for wind energy applications. The low resolution of the 20CR would severely restrict its use on its own for wind farm site-screening. We therefore perform a simple statistical calibration to link it to the higher-resolution ERA-Interim data set (ERAI), such that the adjusted 20CR data has the same wind speed distribution at each location as ERAI during their common period. Using this corrected 20CR data set, wind speeds and variability are characterised in terms of the long-term mean, standard deviation and corresponding trends. Many regions of interest show extremely weak trends on century timescales, but contain large multidecadal variability. Since reanalyses such as ERAI are often used to provide the background climatology for wind farm site assessments, but contain only a few decades of data, our results can be used as a way of incorporating decadal-scale wind climate variability into such studies, allowing investment risks for wind farms to be reduced.  相似文献   

An assessment of the Jenkinson and Collison synoptic classification to a continental mid-latitude location     

Greg?SpellmanEmail author 《Theoretical and Applied Climatology》2017,128(3-4):731-744

A weather-type catalogue based on the Jenkinson and Collison method was developed for an area in south-west Russia for the period 1961–2010. Gridded sea level pressure data was obtained from the National Centers for Environmental Prediction/National Center for Atmospheric Research (NCEP/NCAR) reanalysis. The resulting catalogue was analysed for frequency of individual types and groups of weather types to characterise long-term atmospheric circulation in this region. Overall, the most frequent type is anticyclonic (A) (23.3 %) followed by cyclonic (C) (11.9 %); however, there are some key seasonal patterns with westerly circulation being significantly more common in winter than summer. The utility of this synoptic classification is evaluated by modelling daily rainfall amounts. A low level of error is found using a simple model based on the prevailing weather type. Finally, characteristics of the circulation classification are compared to those for the original JC British Isles catalogue and a much more equal distribution of flow types is seen in the former classification.  相似文献   

Plutonic xenoliths from Martinique,Lesser Antilles: evidence for open system processes and reactive melt flow in island arc crust     

George?F.?CooperEmail author  Jon?P.?Davidson  Jon?D.?Blundy 《Contributions to Mineralogy and Petrology》2016,171(10):87

The Lesser Antilles Volcanic Arc is remarkable for the abundance and variety of erupted plutonic xenoliths. These samples provide a window into the deeper crust and record a more protracted crystallisation history than is observed from lavas alone. We present a detailed petrological and in situ geochemical study of xenoliths from Martinique in order to establish their petrogenesis, pre-eruptive storage conditions and their contribution to construction of the sub-volcanic arc crust. The lavas from Martinique are controlled by crystal–liquid differentiation. Amphibole is rarely present in the erupted lavas, but it is a very common component in plutonic xenoliths, allowing us to directly test the involvement of amphibole in the petrogenesis of arc magmas. The plutonic xenoliths provide both textural and geochemical evidence of open system processes and crystal ‘cargos’. All xenoliths are plagioclase-bearing, with variable proportions of olivine, spinel, clinopyroxene, orthopyroxene and amphibole, commonly with interstitial melt. In Martinique, the sequence of crystallisation varies in sample type and differs from other islands of the Lesser Antilles arc. The compositional offset between plagioclase (~An₉₀) and olivine (~Fo₇₅), suggests crystallisation under high water contents and low pressures from an already fractionated liquid. Texturally, amphibole is either equant (crystallising early in the sequence) or interstitial (crystallising late). Interstitial amphibole is enriched in Ba and LREE compared with early crystallised amphibole and does not follow typical fractionation trends. Modelling of melt compositions indicates that a water-rich, plagioclase-undersaturated reactive melt or fluid percolated through a crystal mush, accompanied by the breakdown of clinopyroxene, and the crystallisation of amphibole. Geothermobarometry estimates and comparisons with experimental studies imply the majority of xenoliths formed in the mid-crust. Martinique cumulate xenoliths are inferred to represent crystal mushes within an open system, through which melt can both percolate and be generated.  相似文献   

Geo-engineering evaluation of Harrat Irbid Basaltic Rocks,Irbid District—North Jordan     

Israa?S.?Abu-MahfouzEmail authorView author&#;s OrcID profile  Ahmad?A.?Al-Malabeh  Shaher?M.?Rababeh 《Arabian Journal of Geosciences》2016,9(5):412

The basalt flow in Irbid district covers an area of about 300 km² and forms different shapes: elongated strips, sub-rounded spots, and arc-like outcrops. The basalt flow in the study area has thicknesses ranging from 1 to 30 m. This study is conducted to evaluate the basaltic rocks as a construction material in eight different places of Harrat Irbid. Thirty-six rock cores were prepared from the collected fresh basaltic rock samples to study the physical and mechanical properties. The basaltic rocks in the study area have desirable physical and mechanical properties; the rocks have high apparent specific gravity values (2.70–2.90), bulk specific gravity (2.60–2.84), absorption values (0.33–1.60 %) that indicates the texture is crystalline, porosity (0.22–2.15 %), void ratio (0.002–0.022), water content (0.35–1.08 %), degree of saturation (41–68 %), rebound number of Schmidt hammer hardness test (average 44.10), point load strength(average 11.35 MPa),uniaxial strength (average 106.83 MPa) which is classified as medium strength, basalt uniformity of wear (0.206), and very high durability which is equal to 99.52 % in average, recorded after the second cycle of the test. Based on field observations and physical and mechanical tests, this study confirms that the genesis of basalt in the study area is strongly related to Harrat Al-Shaam basalt. Therefore, this study adds a new area of about 300 km² to the Harrat Al-Shaam area. Additionally, this study strongly recommends the use of the basaltic rocks that have been tested in this study for some industrial applications (e.g., in construction).  相似文献   

Ecology of Vibrios in the Oliveri-Tindari Lagoon (Messina), Two-Year Study     

Renata  Zaccone  Ermanno  Crisafi Lucrezia  Genovese 《Marine Ecology》1992,13(2):149-161

Abstract. A two-year ecological study in the Oliveri-Tindari (Messina) brackish water ponds evaluated the quantitative and qualitative distribution of Vibrio species in relation to the physicochemical conditions of the ponds.
The evaluation of 204 samples shows a general relationship between the halophilic vibrios and water temperature. In particular this relationship is stronger for the Vibrio fraction able to grow at 37°C, i. e. , those species related to human infections. On the other hand, the halophilic vibrios show no relation with the index of fecal contamination.
The ecology of V. parahaemolyticus is discussed in relation to the salinity of Marinello pond.
The distribution of V. cholerae non O1, isolated from all ponds, shows that this microorganism can be considered as autochthonous in coastal environments.  相似文献   

Late‐Holocene wind‐field evolution at the southern Baltic coast as revealed by GPR data from the Mrzeżyno dunefield,NW Poland     

Tomasz Żuk  Paweł Sydor  Gregory H. Sambrook Smith 《Boreas: An International Journal of Quaternary Research》2017,46(3):470-485

All dunes within a dunefield usually show a similar response to the wind regime. However, in the late‐Holocene coastal dunefield in NW Poland the surface topography suggests that slipface orientation may vary significantly with distance from the coast, which is rarely reported in the literature. The dunefield was stabilized with forest in the mid‐19th century, preserving a unique record of atmospheric circulation in the South Baltic region at the end of the Little Ice Age. To elucidate the Holocene processes occurring along the study site a pseudo‐3D GPR data set was collected. Six grids of parallel GPR lines combined with 400 m of GPR profiles (2D) were collected across the dunefield and displayed using GOCAD for interpretation and geostatistical analysis. The geophysical data revealed that the larger dunes almost entirely consist of steeply laminated facies. Most importantly the pseudo‐3D data, supported by geostatistical estimates of strata dip directions, revealed the existence of three zones parallel to the coastline with the mean dip direction almost perpendicular to the coast in the northern coastal strip and almost parallel to it in the southern part. Spreads of the dip directions in pseudo‐3D GPR data sets recorded on the stoss slopes of dunes and crests suggested initial deposition on transverse dunes, which later were transformed into barchanoid dunes. This can probably be linked to changes in the wind regime, i.e. reduction in velocity of the northern and northwestern winds leading to reduced sediment supply from the coast. While the data provide a new interpretation of Holocene dunefield dynamics at this site, they also suggest that the minimum number of pseudo‐3D GPR grids required to establish general trends using geostatistical analysis should be at least 10, with even more data needed at larger, or more complex dunefields.  相似文献   

Nitrate transport in the unsaturated zone: a case study of the riverbank filtration system Karany,Czech Republic     

Frantisek Buzek  Renata Kadlecova  Ivana Jackova  Zdena Lnenickova 《水文研究》2012,26(5):640-651

Nitrate transport in the unsaturated zone of a riverbank filtration (RBF) system in Karany, Czech Republic, was studied. Previous study of the system estimated RBF recharge as 60% riverbank filtrate and 40% local groundwater contaminated by nitrates. Nitrate concentrations observed in RBF recently cannot be explained by simple groundwater contamination and a new conception of groundwater recharge is suggested. A two‐component model based on water ¹⁸O data modelled recharge of local groundwater. One component of groundwater recharge is rainfall and irrigation water moving through the unsaturated zone of the Quaternary sediments in piston flow. The second component is groundwater from the Cretaceous deposits with a free water table. Both the components of groundwater recharge have different nitrate concentrations, and resulting contamination of groundwater depends on the participation of water from Quaternary and Cretaceous deposits. Nitrates' origins and their mixing in the subsurface were traced by ¹⁵N data. Nitrate transport from the unsaturated zone is important and time variable source of groundwater contamination. Copyright © 2011 John Wiley & Sons, Ltd.  相似文献   

Monument-antenna effects on GPS coordinate time series with application to vertical rates in Antarctica     

Matt?A.?KingEmail author  Michael?Bevis  Terry?Wilson  Bjorn?Johns  Frederick?Blume 《Journal of Geodesy》2012,86(1):53-63

We examine the electromagnetic coupling of a GPS antenna–monument pair in terms of its simulated affect on long GPS coordinate time series. We focus on the Earth and Polar Observing System (POLENET) monument design widely deployed in Antarctica and Greenland in projects interested particularly in vertical velocities. We base our tests on an absolute robot calibration that included the top ~0.15 m of the monument and use simulations to assess its effect on site coordinate time series at eight representative POLENET sites in Antarctica over the period 2000.0–2011.0. We show that the neglect of this calibration would introduce mean coordinate bias, and most importantly for velocity estimation, coordinate noise which is highly sensitive to observation geometry and hence site location and observation period. Considering only sub-periods longer than 2.5 years, we show vertical site velocities may be biased by up to ±0.4 mm/year, and biases up to 0.2 mm/year may persist for observation spans of 8 years. Changing between uniform and elevation-dependent observation weighting alters the time series but does not remove the velocity biases, nor does ambiguity fixing. The effect on the horizontal coordinates is negligible. The ambiguities fixed series spectra show noise between flicker and random walk with near-white noise at the highest frequencies, with mean spectral indices (frequencies <20 cycles per year) of approximately −1.3 (uniform weighting) and −1.4 (elevation-dependent weighting). While the results are likely highly monument specific, they highlight the importance of accounting for monument effects when analysing vertical coordinate time series and velocities for the highest precision and accuracy geophysical studies.  相似文献   

Tectonic history of the hatay ophiolites (South Turkey) and their relation with the dead sea rift     

C. Tinkler  J.-J. Wagner  M. Delaloye  H. Seluk 《Tectonophysics》1981,72(1-2)

The Kizildağ ophiolite massif lies in the Hatay region of S. Turkey. Some structural relationships in the area are examined and two geological sections through the ophiolite are presented.A sequence of structural events, dealing with the emplacement and post-emplacement history, is established. The significance of the events is discussed and it is suggested that the post-emplacement structural history was dominated by movements along the Dead Sea Rift.  相似文献   

Electromechanical phenomena associated with earthquakes   总被引：2，自引：0，他引：2  

Renata Dmowska 《Surveys in Geophysics》1977,3(2):157-174

This article reviews the field, laboratory, and theoretical investigations made concerning different electromechanical phenomena associated with earthquakes. It discusses laboratory measurements of electrical resistivity of rocks stressed up to fracture, particular attention being paid to the interpretation of results according to the diffusion-dilatancy theory. This is followed by the discussion of field measurements of electrical characteristics of rocks in seismic areas in connections with seismic activity in these regions. Piezoelectric and electrostrictive phenomena are briefly discussed, and also a theoretical model of electro-elastic effects associated with an earthquake source. The last part concerns electrokinetic phenomena in porous rocks, caused by the diffusion of fluids into the dilatant focal region. The divergence of opinion about the physical models of the earthquake process is emphasized.  相似文献