Late Pleistocene fluvial dynamics in the Hochrhein Valley and in the Upper Rhine Graben: chronological frame     

Manfred Frechen  Dietrich Ellwanger  Matthias Hinderer  Jörg Lämmermann-Barthel  Inge Neeb  Astrid Techmer 《International Journal of Earth Sciences》2010,99(8):1955-1974

During the Pleistocene, the Rhine glacier system acted as a major south–north erosion and transport medium from the Swiss Alps into the Upper Rhine Graben, which has been the main sediment sink forming low angle debris fans. Only some aggradation resulted in the formation of terraces. Optically stimulated luminescence (OSL) and radiocarbon dating have been applied to set up a more reliable chronological frame of Late Pleistocene and Holocene fluvial activity in the western Hochrhein Valley and in the southern part of the Upper Rhine Graben. The stratigraphically oldest deposits exposed, a braided-river facies, yielded OSL age estimates ranging from 59.6 ± 6.2 to 33.1 ± 3.0 ka. The data set does not enable to distinguish between a linear age increase triggered by a continuous autocyclical aggradation or two (or more) age clusters, for example around 35 ka and around 55 ka, triggered by climate change, including stadial and interstadial periods (sensu Dansgaard–Oeschger cycles). The braided river facies is discontinuously (hiatus) covered by coarse-grained gravel-rich sediments deposited most likely during a single event or short-time period of major melt water discharge postdating the Last Glacial Maximum. OSL age estimates of fluvial and aeolian sediments from the above coarse-grained sediment layer are between 16.4 ± 0.8 and 10.6 ± 0.5 ka, and make a correlation with the Late Glacial period very likely. The youngest fluvial aggradation period correlates to the beginning of the Little Ice Age, as confirmed by OSL and radiocarbon ages.  相似文献   

On the Effect of Surface Heat-Flux Heterogeneities on the Mixed-Layer-Top Entrainment   总被引：1，自引：1，他引：0  

Matthias Sühring  Björn Maronga  Florian Herbort  Siegfried Raasch 《Boundary-Layer Meteorology》2014,151(3):531-556

We used a set of large-eddy simulations to investigate the effect of one-dimensional stripe-like surface heat-flux heterogeneities on mixed-layer top entrainment. The profiles of sensible heat flux and the temporal evolution of the boundary-layer depth revealed decreased entrainment for small heat-flux amplitudes and increased entrainment for large heat-flux amplitudes, compared to the homogeneously-heated mixed layer. For large heat-flux amplitudes the largest entrainment was observed for patch sizes in the order of the boundary-layer depth, while for significantly smaller or larger patch sizes entrainment was similar as in the homogeneous case. In order to understand the underlying physics of this impact, a new approach was developed to infer local information on entrainment by means of the local flux divergence. We found an entrainment maximum over the centre of the stronger heated surface patch, where thermal energy is accumulated by the secondary circulation (SC) that was induced by the surface heterogeneity. Furthermore, we observed an entrainment maximum over the less heated patch as well, which we suppose is to be linked to the SC-induced horizontal flow convergence at the top of the convective boundary layer (CBL). For small heat-flux amplitudes a counteracting effect dominates that decreases entrainment, which we suppose is the horizontal advection of cold air in the lower, and warm air in the upper, CBL by the SC, stabilizing the CBL and thus weakening thermal convection. Moreover, we found that a mean wind can reduce the heterogeneity-induced impact on entrainment. If the flow is aligned perpendicular to the border between the differentially-heated patches, the SC and thus its impact on entrainment vanishes due to increased horizontal mixing, even for moderate wind speeds. However, if the flow is directed parallel to the border between the differentially-heated patches, the SC and thus its impact on entrainment persists.  相似文献   

Tropical and extratropical cyclone damages under climate change     

Matthew Ranson  Carolyn Kousky  Matthias Ruth  Lesley Jantarasami  Allison Crimmins  Lisa Tarquinio 《Climatic change》2014,127(2):227-241

This paper provides the first quantitative synthesis of the rapidly growing literature on future tropical and extratropical cyclone damages under climate change. We estimate a probability distribution for the predicted impact of changes in global surface air temperatures on future storm damages, using an ensemble of 478 estimates of the temperature-damage relationship from nineteen studies. Our analysis produces three main empirical results. First, we find strong but not conclusive support for the hypothesis that climate change will cause damages from tropical cyclones and wind storms to increase, with most models predicting higher future storm damages due to climate change. Second, there is substantial variation in projected changes in losses across regions. Potential changes in damages are greatest in the North Atlantic basin, where the multi-model average predicts that a 2.5 °C increase in global surface air temperature would cause hurricane damages to increase by 63 %. The ensemble predictions for Western North Pacific tropical cyclones and European wind storms (extratropical cyclones) are +28 % and +23 %, respectively. Finally, our analysis shows that existing models of storm damages under climate change generate a wide range of predictions, ranging from moderate decreases to very large increases in losses.  相似文献   

Compliance for uncertain inventories via probabilistic/fuzzy comparison of alternatives     

Olgierd Hryniewicz  Zbigniew Nahorski  Jörg Verstraete  Joanna Horabik  Matthias Jonas 《Climatic change》2014,124(3):519-534

A direct comparison among highly uncertain inventories of emissions is inadequate and may lead to paradoxes. This issue is of particular importance in the case of greenhouse gases. This paper reviews the methods for the comparison of uncertain inventories in the context of compliance checking. The problem is treated as a comparison of uncertain alternatives. It provides a categorization and ranking of the inventories which can induce compliance checking conditions. Two groups of techniques to compare uncertain estimates are considered in the paper: probabilistic and fuzzy approaches. They show certain similarities which are revealed and stressed throughout the paper. The group of methods most suitable for the compliance purpose is distinguished. They introduce new conditions for fulfilling compliance, depending on inventory uncertainty. These new conditions considerably change the present approach, where only the reported values of inventories are accounted for.  相似文献   

Enhancing the relevance of Shared Socioeconomic Pathways for climate change impacts,adaptation and vulnerability research   总被引：1，自引：1，他引：0  

Bas J. van Ruijven  Marc A. Levy  Arun Agrawal  Frank Biermann  Joern Birkmann  Timothy R. Carter  Kristie L. Ebi  Matthias Garschagen  Bryan Jones  Roger Jones  Eric Kemp-Benedict  Marcel Kok  Kasper Kok  Maria Carmen Lemos  Paul L. Lucas  Ben Orlove  Shonali Pachauri  Tom M. Parris  Anand Patwardhan  Arthur Petersen  Benjamin L. Preston  Jesse Ribot  Dale S. Rothman  Vanessa J. Schweizer 《Climatic change》2014,122(3):481-494

This paper discusses the role and relevance of the shared socioeconomic pathways (SSPs) and the new scenarios that combine SSPs with representative concentration pathways (RCPs) for climate change impacts, adaptation, and vulnerability (IAV) research. It first provides an overview of uses of social–environmental scenarios in IAV studies and identifies the main shortcomings of earlier such scenarios. Second, the paper elaborates on two aspects of the SSPs and new scenarios that would improve their usefulness for IAV studies compared to earlier scenario sets: (i) enhancing their applicability while retaining coherence across spatial scales, and (ii) adding indicators of importance for projecting vulnerability. The paper therefore presents an agenda for future research, recommending that SSPs incorporate not only the standard variables of population and gross domestic product, but also indicators such as income distribution, spatial population, human health and governance.  相似文献   

The Water Framework Directive: Can more information be extracted from groundwater data? A case study of Seewinkel,Burgenland, eastern Austria     

István Gábor Hatvani  Norbert Magyar  Matthias Zessner  József Kovács  Alfred Paul Blaschke 《Hydrogeology Journal》2014,22(4):779-794

Water protection is one of the most important goals in environmental protection. The Clean Water Act in the USA and the Water Framework Directive (WFD) in Europe are the legal frameworks to facilitate the achievement of this goal. The question is raised of whether more information can be extracted from WFD-related groundwater data. To answer it, a methodology has been developed that is easy to use and could be implemented into official practice. A case study is presented in which the groundwater data of a sodic area in Austria (Seewinkel) is assessed. Eighteen parameters in groundwater sampled from 23 wells (1991–2011) were analyzed. With basic statistics, trend-, cluster-, Wilks’ λ and spatial sampling density analysis, local phosphorus and boron phenomena were described, along with the determining role of sulphate, groundwater flow, and the oxygen gradient in the area. As a final step, the spatial sampling density was determined. Regarding the current set of parameters, all the sampling sites are necessary and only in the case of certain parameters (Ca²⁺, Mg²⁺, K⁺, NO₃ ^?, pH) could one sampling site be abandoned. The methodology applied brings a new perspective to exploring groundwater data collected according to the requirements of the WFD.  相似文献   

Thermochronological evidence for Mio‐Pliocene late orogenic extension in the north‐eastern Albanides (Albania)     

Bardhyl Muceku  Peter Van Der Beek  Matthias Bernet  Peter Reiners  Georges Mascle  Artan Tashko 《地学学报》2008,20(3):180-187

New apatite and zircon (U–Th)/He and apatite fission‐track (FT) data allow constraining the timing of Miocene–Pliocene extensional exhumation that affected the central part of the Dinarides‐Albanides‐Hellenides orogen. Apatite (U–Th)/He ages in the northern and western Internal Albanides range from 57 to 17 Ma, contrasting to younger ages of 5.2–9.3 Ma in the eastern Internal Albanides. Eastward younging is also reflected in zircon (U–Th)/He ages varying from 101 Ma in the north‐western Internal Albanides to 19–50 Ma in the east, as well as in recently published apatite FT ages. Thermal history predictions with the new data point to a phase of rapid exhumation of the eastern Internal Albanides around 6–4 Ma, while the western Internal Albanides record slower continuous exhumation since the Eocene. This asymmetric exhumation pattern is most likely linked to extensional reactivation of NE–SW‐trending thrusts east of the Mirdita zone and within the Korabi zone of the eastern Internal Albanides.  相似文献   

Heterogeneity-Induced Heat-Flux Patterns in the Convective Boundary Layer: Can they be Detected from Observations and is There a Blending Height?—A Large-Eddy Simulation Study for the LITFASS-2003 Experiment     

Matthias Sühring  Siegfried Raasch 《Boundary-Layer Meteorology》2013,148(2):309-331

An understanding of how the convective boundary layer (CBL) is mixed under heterogeneous surface forcing is crucial for the interpretation of area-averaged turbulence measurements. To determine the height and degree to which a complex heterogeneous surface affects the CBL, large-eddy simulations (LES) for two days of the LITFASS-2003 experiment representing two different wind regimes were undertaken. Spatially-lagged correlation analysis revealed the turbulent heat fluxes to be dependent on the prescribed surface flux pattern throughout the entire CBL including the entrainment layer. These findings prompted the question of whether signals induced by surface heterogeneity can be measured by airborne systems. To examine this question, an ensemble of virtual flights was conducted using LES, according to Helipod flight measurements made during LITFASS-2003. The resulting ensemble-averaged heat fluxes indicated a clear dependence on the underlying surface up to the top of the CBL. However, a large scatter between the flux measurements in different ensemble runs was observed, which was the result of insufficient sampling of the largest turbulent eddies. The random and systematic errors based on the integral length scale did not indicate such a large scatter. For the given flight leg lengths, at least 10–15 statistically independent flight measurements were necessary to give a significant estimate of heterogeneity-induced signals in the CBL. The need for ensemble averaging suggests that the observed blending of heterogeneity-induced signals in the CBL can be partly attributed to insufficient averaging.  相似文献   

Erratum to: Non-stationary Generation of Weak Turbulence for Very Stable and Weak-Wind Conditions     

Larry Mahrt  Christoph Thomas  Scott Richardson  Nelson Seaman  David Stauffer  Matthias Zeeman 《Boundary-Layer Meteorology》2013,147(2):201-201

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A Comment on “How Well Can We Measure the Vertical Wind Speed? Implications for Fluxes of Energy and Mass” by Kochendorfer et al.     

Matthias?MauderEmail author 《Boundary-Layer Meteorology》2013,147(2):329-335

Kochendorfer et al. (Boundary-Layer Meterol, 145:383–398, 2012) conducted an experiment to evaluate azimuth and angle-of-attack dependent errors of sonic anemometer measurements. Several questions are raised regarding the experimental design and the presented results. The finding that instruments with non-orthogonal sonic paths underestimate fluctuations of vertical wind speed and consequently also scalar fluxes by about 10 % is compared with the results of a hitherto unpublished side-by-side field comparison and other past intercomparison experiments. Scale considerations are presented that raise considerable doubts on the validity of the implicit assumption of Kochendorfer et al. (2012) that the turbulent wind vector is highly correlated across a distance of 1.2 m at a height of 2.5 m over flat grassland, which corresponds to the separation between the sonic anemometers tested in their experiment. Nevertheless, new developments in sonic anemometer design to minimize transducer-shadow effects are desirable.  相似文献