Sensitivity of transient climate change to tidal mixing: Southern Ocean heat uptake in climate change experiments performed with ECHAM5/MPIOM     

E. Exarchou  J.-S. von Storch  J. H. Jungclaus 《Climate Dynamics》2014,42(7-8):1755-1773

We investigate the sensitivity of the transient climate change to a tidal mixing scheme. The scheme parameterizes diapycnal diffusivity depending on the location of energy dissipation over rough topography, whereas the standard configuration uses horizontally constant diffusivity. We perform ensemble climate change experiments with two setups of MPIOM/ECHAM5, one setup with the tidal mixing scheme and the second setup with the standard configuration. Analysis of the responses of the transient climate change to CO₂ increase reveals that the implementation of tidal mixing leads to a significant reduction of the transient surface warming by 9 %. The weaker surface warming in the tidal run is localized particularly over the Weddell Sea, likely caused by a stronger ocean heat uptake in the Southern Ocean. The analysis of the ocean heat budget reveals that the ocean heat uptake in both experiments is caused by changes in convection and advection. In the upper ocean, heat uptake is caused by reduced convection and enhancement of the Deacon Cell, which appears also in isopycnal coordinates. In the deeper ocean, heat uptake is caused by reduction of convective cooling associated with the circulation polewards of 65°S. Tidal mixing leads to stronger heat uptake in the Southern Ocean by causing stronger changes in advection, namely a stronger increase in the Deacon Cell and a stronger reduction in advective cooling by the circulation polewards of 65°S. Counter-intuitively, the relation between tidal mixing and greater heat storage in the deep ocean is an indirect one, through the influence of tidal mixing on the circulation.  相似文献   

Polar Low genesis over the North Pacific under different global warming scenarios   总被引：1，自引：1，他引：0  

Fei Chen  Hans von Storch  Lili Zeng  Yan Du 《Climate Dynamics》2014,43(12):3449-3456

Following an earlier climatological study of North Pacific Polar Lows by employing dynamical downscaling of NCEP1 reanalysis in the regional climate model COSMO-CLM, the characteristics of Polar Low genesis over the North Pacific under different global warming scenarios are investigated. Simulations based on three scenarios from the Special Report on Emissions Scenarios were conducted using a global climate model (ECHAM5) and used to examine systematic changes in the occurrence of Polar Lows over the twenty first century. The results show that with more greenhouse gas emissions, global air temperature would rise, and the frequency of Polar Lows would decrease. With sea ice melting, the distribution of Polar Low genesis shows a northward shift. In the scenarios with stronger warming there is a larger reduction in the number of Polar Lows.  相似文献   

Anthropogenic influence of trace metals in sediments of the Al-Qilt catchment,West Bank,Palestine: 1. Contamination factor and bonding forms     

Sobhi Samhan  Kurt Friese  Wolf von Tümpling  Herbert Pöllmann  Heinz Hoetzl  Marwan Ghanem 《Environmental Earth Sciences》2014,71(4):1533-1539

Al-Qilt catchment, located east of both the Ramallah and Jerusalem districts is strongly influenced by waste waters discharged from Israeli settlements and Palestinian urban centers. In this research, our aim was to verify the chemical status of the surface sediments from the Al-Qilt catchment during 2008/2009. For this purpose, 36 surface sediment samples were collected and analyzed with ICP/MS within the fraction of below 63 μm. The extent of contamination of trace metals from Al-Qilt sediments sites were measured by evaluating the contamination factors (CF) from digestion by aqua regia and additionally by sequential extraction steps using the BCR-method. On the basis of the calculated CF, sediments appear particularly contaminated with Zn, Cu, Ag, Sn, Cd, Hg, Bi, and B. Three regions, Wadi Sweanit, Ras Al-Qilt, and Qalandiah have been identified as critical points of contamination. Trace metal inputs to the Al-Qilt catchment need to be kept under strict control in the future since Ras Al-Qilt is considered as one of the important springs in the area and is used for domestic purposes. Moreover, it will be susceptible to pollution if no action is taken to decrease the pollution at the upstream of Al-Qilt.  相似文献   

Genetic relationship between silver–lead–zinc mineralization in the Wutong deposit,Guangxi Province and Mesozoic granitic magmatism in the Nanling belt,southeast China     

Pilar Lecumberri-Sanchez  Rolf L. Romer  Volker Lüders  Robert J. Bodnar 《Mineralium Deposita》2014,49(3):353-369

More than 50 % of the world's total reserves of tungsten are in China and most tungsten deposits are located in the Nanling range in southeast China. This study explores the potential genetic relationship between tungsten–tin (W–Sn) mineralization and shallower Ag–Pb–Zn deposits in the Nanling range based on data from the Wutong deposit, Guangxi Province. The lead, oxygen, carbon, sulfur, and strontium isotopic compositions of minerals at Wutong indicate that a single crustal-derived fluid was responsible for mineralization. Wutong likely formed at relatively low temperatures (～200–300 °C) and low pressures, as indicated by the similarity between homogenization temperatures of fluid inclusions and those estimated from S isotopic compositions of minerals. The hübnerite age (92.3–104.4 Ma) indicates that the Wutong mineralization is likely related to nearby Late Yanshanian (Cretaceous) S-type granites derived from Proterozoic crust. This mineralization event coincides with the last W–Sn mineralization event and the Cretaceous peak of mineralization in the Nanling range.  相似文献   

Geochemistry of Neogene quartz andesites from the Oaş and Gutâi Mountains,Eastern Carpathians (Romania): a complex magma genesis     

Maria Jurje  Corina Ionescu  Volker Hoeck  Marinel Kovacs 《Mineralogy and Petrology》2014,108(1):13-32

The Neogene quartz andesites from the Oa? and Gutâi Mountains (Romania) are mid-K calc-alkaline rocks and contain plagioclase-orthopyroxene-clinopyroxene-amphibole-magnetite phenocrysts as well as quartz crystals. They are associated with a volcanic sequence ranging from basalts and basaltic andesites to dacites and rhyolites, but form a separate magma group, mostly in respect to the trace elements. Based on the geochemical data combined with inferences from complex zoning patterns in plagioclase and pyroxene, the evolution of quartz andesites is interpreted in terms of fractional crystallization, AFC and magma mixing. A parental magma deriving from a MORB- or OIB-type source modified by fluids and melts originating from sediments is envisaged.  相似文献   

Franz-Ludwig Deubner (1934 – 2017)     

Bernhard Fleck  Oskar von der Lühe 《Solar physics》2017,292(12):178

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Boundary layer ion composition at Jupiter during the inbound pass of the Ulysses flyby     

A.B. Galvin  C.M.S. Cohen  F.M. Ipavich  R. von Steiger  J. Woch  U. Mall 《Planetary and Space Science》1993,41(11-12)

During the inbound segment of the Ulysses flyby of Jupiter, there were multiple incursions into the dawnside low-latitude boundary layer, as identified by Bame et al. (Science257, 1539–1542, 1992) using plasma electron data. In the present study, ion composition and spectral measurements provide independent collaborative evidence for the existence of distinct boundary layer regions. Measurements are taken in the energy-per-charge range of 0.6–60 keV/e and involve mass as well as mass-per-charge identification by the Ulysses/SWICS experiment. Ion species of Jovian magnetospheric origin (including O⁺, O²⁺, S²⁺, S³⁺) and sheath origin (including He²⁺ and high charge state CNO) have been directly identified for the first time in the Jovian magnetospheric boundary layer. Protons of probably mixed origin and He⁺ of possibly sheath (ultimately interstellar pickup) origin were also observed in the boundary layer. Sheath-like ions are observed throughout the boundary layer; however, the Jovian ions are depleted or absent for portions of two boundary layer cases studied. Ions of solar wind origin are observed within the outer magnetosphere. and ions of magnetospheric origin are found within the sheath, indicating that transport across the magnetopause boundary can work both ways, at least under some conditions. Although their source cannot be uniquely identified, the proton energy spectrum in the boundary layer suggests a sheath origin for the lower energy protons.  相似文献   

Cosmic reionization by stellar sources: population III stars     

Aaron Sokasian  Naoki Yoshida  Tom Abel  Lars Hernquist  Volker Springel 《Monthly notices of the Royal Astronomical Society》2004,350(1):47-65

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The formation of close binary systems by dynamical interactions and orbital decay     

Matthew R. Bate  Ian A. Bonnell  Volker Bromm 《Monthly notices of the Royal Astronomical Society》2002,336(3):705-713

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Derivation of planetary topography using multi-image shape-from-shading   总被引：1，自引：0，他引：1  

Volker Lohse  Christian Heipke 《Planetary and Space Science》2006,54(7):661-674

In many cases, the derivation of high-resolution digital terrain models (DTMs) from planetary surfaces using conventional digital image matching is a problem. The matching methods need at least one stereo pair of images with sufficient texture. However, many space missions provide only a few stereo images and planetary surfaces often possess insufficient texture.This paper describes a method for the generation of high-resolution DTMs from planetary surfaces, which has the potential to overcome the described problem. The suggested method, developed by our group, is based on shape-from-shading using an arbitrary number of digital optical images, and is termed “multi-image shape-from-shading” (MI-SFS). The paper contains an explanation of the theory of MI-SFS, followed by a presentation of current results, which were obtained using images from NASA's lunar mission Clementine, and constitute the first practical application with our method using extraterrestrial imagery. The lunar surface is reconstructed under the assumption of different kinds of reflectance models (e.g. Lommel-Seeliger and Lambert). The represented results show that the derivation of a high-resolution DTM of real digital planetary images by means of MI-SFS is feasible.  相似文献