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Sensitivity of East Asian Climate to the Progressive Uplift and Expansion of the Tibetan Plateau Under the Mid-Pliocene Boundary Conditions

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Advances in Atmospheric Sciences 2008年第5期25卷 709-722页

作者：姜大膀丁仲礼 helge DRANGE 郜永祺 Nansen-Zhu International Research Centre Institute of Atmospheric PhysicsChinese Academy of Sciences Institute of Geology and Geophysics Chinese Academy of Sciences Nansen Environmental and Remote Sensing Centre Bergen N-5006 Norway

A global atmospheric general circulation model has been used to perform eleven idealized numerical experiments, i.e., TP10, TP10, .., TP100, corresponding to different percentages of the Tibetan Plateau altitude. The aim is to explore the sensitivity of East Asian climate to the uplift and expansion of the Tibetan Plateau under the reconstructed boundary conditions for the mid-Pliocene about 3 Ma ago. When the plateau is progressively uplifted, global annual surface temperature is gradually declined and statistically significant cooling signals emerge only in the Northern Hemisphere, especially over and around the Tibetan Plateau, with larger magnitudes over land than over the oceans. On the contrary, annual surface temperature rises notably over Central Asia and most parts of Africa, as well as over northeasternmost Eurasia in the experiments TP60 to TP100. Meanwhile, the plateau uplift also leads to annual precipitation augmentation over the Tibetan Plateau but a reduction in northern Asia, the Indian Peninsula, much of Central Asia, parts of western Asia and the southern portions of northeastern Europe. Additionally, it is found that an East Asian summer monsoon system similar to that of the present initially exists in the TP60 and is gradually intensified with the continued plateau uplift. At 850 hPa the plateau uplift induces an anomalous cyclonic circulation around the Tibetan Plateau in summertime and two anomalous westerly currents respectively located to the south and north of the Tibetan Plateau in wintertime. In the mid-troposphere, similarto-modern spatial pattern of summertime western North Pacific subtropical high is only exhibited in the experiments TP60 to TP100, and the East Asian trough is steadily deepened in response to the progressive uplift and expansion of the Tibetan Plateau.

关键词： Tibetan Plateau uplift East Asian climate mid-Pliocene model

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Auditory nerve preservation and regeneration in man:relevance for cochlear implantation

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Neural Regeneration Research 2015年第5期10卷 710-712页

作者： helge Rask-Andersen Wei Liu Department of Surgical Sciences Head and Neck SurgerySection of OtolaryngologyUppsala University Hospital Departments of Otolaryngology Uppsala University Hospital

Human hearing relies on 15,000 hair cells （HCs） or mecha- noreceptors sited in a 34 mm long helical shaped epithelial ridge. There may be several explanations for their vulner- ability in man and regrettably, they do not regenerate. Ap- proximately 35,000 bipolar neurons have their soma situated in the modiolus of the cochlea. Human afferents consist of two separate systems; one is represented by the large type I cells innervating the inner HCs （IHCs, n = 3,400） and the other one by the small type Ⅱcells innervating the outer HCs （OHCs, n = 12,000）. Type I spiral ganglion neurons （SGNs） constitute 96% of the afferent nerve population. Unlike in other mammals, their somas together with the pre- and post-somatic segments are unmyelinated. Type II nerve cell soma and fibers are unmyelinated.

关键词： cell Auditory nerve preservation and regeneration in man

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Diapycnal Mixing in Transient Responses of the Atlantic Meridional Overturning Circulation in an Enhanced Freshwater Perturbation Experiment

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Atmospheric and Oceanic Science Letters 2010年第4期3卷 201-206页

作者： helge DRANGE Odd helge OTTER Nansen-Zhu International Research Centre Institute of Atmospheric PhysicsChinese Academy of Sciences Nansen Environmental and Remote Sensing Center/Bjerknes Centre for Climate Research

It has been reported recently that the simulated Atlantic meridional overturning circulation(AMOC) using the coupled Bergen climate model(BCM) showed initial intensity declines followed by gradual recoveries over a 150-year enhanced freshwater input ***-dependent oceanic diapycnal mixing has been hypothesized as a reason for the simulated recovery of the *** study investigated the role of diapycnal mixing in transient responses of simulated *** results showed that stratification-dependent diapycnal mixing can cause stronger upwelling of deep water in the tropical Atlantic than that produced under conditions of fixed diapycnal ***,simulated AMOCs were more sensitive to active stratification-dependent diapycnal mixing than fixed ***,stratification-dependent diapycnal mixing cannot be conclusively singled out as the critical cause of the recoveries of simulated AMOCs under enhanced-freshwater inputs.

关键词： diapycnal mixing western tropical North Atlantic freshwater experiment

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Revisiting Effect of Ocean Diapycnal Mixing on Atlantic Meridional Overturning Circulation Recovery in a Freshwater Perturbation Simulation

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Advances in Atmospheric Sciences 2008年第4期25卷 597-609页

作者：于雷郜永祺王会军 helge DRANGE Nansen-Zhu International Research Center Institute of Atmospheric PhysicsChinese Academy of Sciences

The effects of ocean density vertical stratification and related ocean mixing on the transient response of the Atlantic meridional overturning circulation （AMOC） are examined in a freshwater perturbation simulation using the Bergen Climate Model （BCM）. The results presented here are based on the model outputs of a previous freshwater experiment： a 300-year control integration （CTRL）, a freshwater integration （FW1） which started after 100 years of running the CTRL with an artificially and continuously threefold increase in the freshwater flux to the Greenland-Iceland-Norwegian （GIN） Seas and the Arctic Ocean throughout the following 150-year simulation. In FW1, the transient response of the AMOC exhibits an initial decreasing of about 6 Sv （1 Sv=106 m3 s^-1） over the first 50-year integration and followed a gradual recovery during the last 100-year integration. Our results show that the vertical density stratification as the crucial property of the interior ocean plays an important role for the transient responses of AMOC by regulating the convective and diapycnal mixings under the enhanced freshwater input to northern high latitudes in BCM in which the ocean diapycnal mixing is stratification-dependent. The possible mechanism is also investigated in this paper.

关键词： North Atlantic meridional overturning circulation enhanced freshwater forcing, diapycnal mixing

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Computer Experiments on Rapidly Rotating Plane Couette Flow

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Communications in Computational Physics 2010年第4期7卷 683-717页

作者： Mustafa Barri helge I.Andersson Fluids Engineering Division Department of Energy and Process EngineeringNorwegian University of Science and Technology7491 TrondheimNorway

The turbulence in plane Couette flow subjected to system rotation is investigated. The anti-cyclonic rotation rate is well above the range in which roll-cells occurand close to the upper bound, beyond which no stationary turbulent states of motionexist. The mean velocity profile exhibits a linear region over 80% of the cross-section, inwhich the mean absolute vorticity is driven to zero. Viscous effects still prevail in narrow regions next to the walls, whereas the quasi-homogeneous central core exhibitsabnormal anisotropies of the Reynolds stress tensor, the vorticity tensor and the energy dissipation rate tensor. In spite of the distinctly higher turbulence level observed,a 13% drag reduction is found. This paradoxical finding is ascribed to configurationalchanges in the turbulence field brought about by the system rotation.

关键词： Turbulence plane Couette flow system rotation anti-cyclonic rotation anisotropy tensor zero absolute mean vorticity

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Statistics of Particle Suspensions in Turbulent Channel Flow

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Communications in Computational Physics 2012年第4期11卷 1311-1322页

作者： Lihao Zhao helge I.Andersson Fluids Engineering Division Department of Energy and Process EngineeringNorwegian University of Science and Technology7491 TrondheimNorway

Particle dynamics in a turbulent channel flow is *** effects of particle concentration and Reynolds number on the particle velocity statistics are *** different particle response times,τ^(+)=1,5,30 and 100,are examined for three different Reynolds numbers,Re_(∗)=200,360 and 790(based on channel height and friction velocity).The particle concentration evolves with time and statistics obtained during three different sampling periods might be distinctly *** and fluctuating particle velocities are substantially affected both by the particle response time and by the Reynolds number of the flow.

关键词： Spherical particles DNS turbulence sampling Reynolds number effects

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Diagnosing Ocean Tracer Transport from Sellafield and Dounreay by Equivalent Diffusion and Age

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Advances in Atmospheric Sciences 2008年第5期25卷 805-814页

作者： Steinar ORRE Yongqi GAO helge DRANGE Eric DELEERSNIJDER Nansen Environmental and Remote Sensing Center Bergen Norway Bjerknes Centre for Climate Research Bergen Norway Nansen-Zhu International Research Centre Institute of Atmospheric Physics （ IAP） Chinese Academy of Sciences （ CAS） Beijing 100029 Geophysical Institute University of Bergen Bergen Norway Centre for Systems Engineering and Applied Mechanics （CESAME） Louvain School of Engineering Universite catholique de Louvain Louvain-la-Neuve Belgium

A simple approach for estimating the equivalent diffusion for diagnosing tracer transport is proposed. Two different expressions are derived; one is based directly on an analytical solution of the two-dimensional advection-diffusion equation, the other uses the variance of the tracer distribution. To illustrate some features of the equivalent diffusion and possible applications thereof, idealized releases of passive tracers from the nuclear fuel reprocessing plants at Sellafield in the Irish Sea and Dounreay on the northern coast of Scotland have been simulated with a regional isopycnic co-ordinate Ocean General Circulation Model. Both continuous and pulse releases are considered; the former being representative of the actual historical discharges from the reprocessing plants, the latter resembling an accidental scenario. Age tracers are included to calculate the mean time elapsed since the tracers left their source regions. It is found that in the Nordic Seas the age of tracers from Dounreay is approximately 2 years younger than the age from Sellafield. Although tracers from both sources eventually end up along the same transport routes, significant qualitative differences regarding the dispersion properties are found. It is argued that one single parameter, the equivalent horizontal diffusion, which is estimated to be in the range of 20 56 m^2 s^-1 from Sellafield and 170-485 m^2 s^-1 from Dounreay, determines these differences.

关键词： equivalent diffusion passive tracers age tracers sellafield dounreay

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Changes in the Tropical Cyclone Genesis Potential Index over the Western North Pacific in the SRES A2 Scenario

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Advances in Atmospheric Sciences 2010年第6期27卷 1246-1258页

作者：张颖王会军孙建奇 helge DRANGE Nansen-Zhu International Research Centre Institute of Atmospheric PhysicsChinese Academy of Sciences Climate Change Research Center Chinese Academy of Sciences Graduate University of Chinese Academy of Science Department of Geophysics University of Bergen

The Tropical Cyclone Genesis Potential Index （GPI） was employed to investigate possible impacts of global warming on tropical cyclone genesis over the western North Pacific （WNP）. The outputs of 20th century climate simulation by eighteen GCMs were used to evaluate the models＇ ability to reproduce tropical cyclone genesis via the GPI. The GCMs were found in general to reasonably reproduce the observed spatial distribution of genesis. Some of the models also showed ability in capturing observed temporal variation. Based on the evaluation, the models （CGCM3.1-T47 and IPSL-CM4） found to perform best when reproducing both spatial and temporal features were chosen to project future GPI. Results show that both of these models project an upward trend of the GPI under the SRES A2 scenario, however the rate of increase differs between them.

关键词： Genesis Potential Index tropical cyclone western North Pacific global warming SRES A2

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Super-resolution immunohistochemistry study on CD4 and CD8 cells and the relation to macrophages in human cochlea

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Journal of Otology 2019年第1期14卷 1-5页

作者： Wei Liu helge Rask-Andersen Department of Surgical Sciences Section of OtolaryngologyUppsala University Hospital

Recently, the human cochlea has been shown to contain numerous resident macrophages under steady-state. The macrophages accumulate in the stria vascularis, among the auditory nerves, and are also spotted in the human organ of Corti. These macrophages may process antigens reaching the cochlea by invasion of pathogens and insertion of CI electrode. Thus, macrophages execute an innate, and possibly an adaptive immunity. Here, we describe the molecular markers CD4 and CD8 of T cells, macrophage markers MHCⅡ and CD11b, as well as the microglial markers TEME119 and P2Y12, in the human cochlea. Immunohistochemistry and the advantageous super-resolution structured illumination microscopy(SR-SIM) were used in the study. CD4^+ and CD8^+ cells were found in the human cochleae. They were seen in the modiolus in a substantial number adjacent to the vessels, in the peripheral region of the Rosenthal's canal, and occasionally in the spiral ligament. While there are a surprisingly large number of macrophages in the stria vascularis as well as between the auditory neurons,CD4^+ and CD8^+ cells are hardly seen in these areas, and neither are seen in the organ of Corti. In the modiolus,macrophages, CD4^+ and CD8^+ cells appeared often in clusters. Interaction between these different cells was easily observed with SR-SIM, showing closely placed cell bodies, and the processes from macrophages reaching out and touching the lymphocytes. Otherwise the CD4^+ and CD8^+ cells in human cochlear tissue are discretely scattered. The possible roles of these immune cells are speculated.

关键词： Macrophage Human cochlea CD4 CD8 Lymphocyte T cell

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Limited tree richness effects on herb layer composition,richness and productivity in experimental forest stands

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Journal of Plant Ecology 2017年第1期10卷 190-200页

作者： Markus S.Germany helge Bruelheide Alexandra Erfmeier Institute for Ecosystem Research GeobotanyKiel UniversityOlshausenstr.7524118 KielGermany Institute of Biology/Geobotany and Botanical Garden Martin Luther University Halle-WittenbergAm Kirchtor 106120 HalleGermany German Centre for Integrative Biodiversity Research(iDiv)Halle-Jena-Leipzig Deutscher Platz 5e04103 LeipzigGermany

Aims In forests,the herbaceous understory vegetation plays an important role for ecosystem functioning as it represents a significant component of total aboveground *** addition,the herb layer contributes to overall forest species richness and controls tree species *** versa,trees in the overstory control understory herb and shrub growth through competition for *** an experimental forest plantation with manipulated tree richness,we asked to which degree tree species richness and identity affect herb layer composition,richness and productivity and how these relationships across strata change with abiotic environmental conditions and competition *** In the context of the Biodiversity-Ecosystem Functioning project in subtropical China(BEF-China),we made use of the integrated BEFmod experiment arranged along a tree species richness gradient at two sites,with additional subplot treatments of phosphorus addition,herb layer weeding and no *** recorded the understory vegetation and determined herb layer biomass production on a total of 201 *** Findings We found only minor effects of tree layer richness on herb layer species composition and no significant effect on herb layer richness or productivity ***,there were strong tree layer identity effects on all response variables,which were partly explained by differences in leaf area index and by a high share of woody species both in total herb layer species richness and *** were strong treatment effects,which were largest in the‘no weeding’treatment but we did not find any treatment×tree layer richness interaction in herb layer ***,these effects are mainly explained by increased competition intensity within the herb layer in the absence of *** the young age of the experiment,the interactions between tree species identity,tree richness and the herb layer did already emerge and can be expected to become stronger with

关键词： experimental research platform of BEF-China functional biodiversity research forest understory biomass Jiangxi Province

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