Future changes in daily summer temperature variability: driving processes and role for temperature extremes     

Erich M. Fischer  Christoph Schär 《Climate Dynamics》2009,33(7-8):917-935

Anthropogenic greenhouse gas emissions are expected to lead to more frequent and intense summer temperature extremes, not only due to the mean warming itself, but also due to changes in temperature variability. To test this hypothesis, we analyse daily output of ten PRUDENCE regional climate model scenarios over Europe for the 2071–2100 period. The models project more frequent temperature extremes particularly over the Mediterranean and the transitional climate zone (TCZ, between the Mediterranean to the south and the Baltic Sea to the north). The projected warming of the uppermost percentiles of daily summer temperatures is found to be largest over France (in the region of maximum variability increase) rather than the Mediterranean (where the mean warming is largest). The underlying changes in temperature variability may arise from changes in (1) interannual temperature variability, (2) intraseasonal variability, and (3) the seasonal cycle. We present a methodology to decompose the total daily variability into these three components. Over France and depending upon the model, the total daily summer temperature variability is projected to significantly increase by 20–40% as a result of increases in all three components: interannual variability (30–95%), seasonal variability (35–105%), and intraseasonal variability (10–30%). Variability changes in northern and southern Europe are substantially smaller. Over France and parts of the TCZ, the models simulate a progressive warming within the summer season (corresponding to an increase in seasonal variability), with the projected temperature change in August exceeding that in June by 2–3 K. Thus, the most distinct warming is superimposed upon the maximum of the current seasonal cycle, leading to a higher intensity of extremes and an extension of the summer period (enabling extreme temperatures and heat waves even in September). The processes driving the variability changes are different for the three components but generally relate to enhanced land–atmosphere coupling and/or increased variability of surface net radiation, accompanied by a strong reduction of cloudiness, atmospheric circulation changes and a progressive depletion of soil moisture within the summer season. The relative contribution of these processes differs substantially between models.  相似文献   

Nowcasting of a supercell storm with VERA     

Stefan Schneider  Barbara Chimani  Hildegard Kaufmann  Benedikt Bica  Christoph Lotteraner  Simon Tschannett  Reinhold Steinacker 《Meteorology and Atmospheric Physics》2008,102(1-2):23-36

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Evaluating the impact of visualization of risk upon emergency route-planning     

Lisa Cheong  Christoph Kinkeldey  Ingrid Burfurd  Susanne Bleisch 《International journal of geographical information science》2020,34(5):1022-1050

ABSTRACT

This paper reports on a controlled experiment evaluating how different cartographic representations of risk affect participants’ performance on a complex spatial decision task: route planning. The specific experimental scenario used is oriented towards emergency route-planning during flood response. The experiment compared six common abstract and metaphorical graphical symbolizations of risk. The results indicate a pattern of less-preferred graphical symbolizations associated with slower responses and lower-risk route choices. One mechanism that might explain these observed relationships would be that more complex and effortful maps promote closer attention paid by participants and lower levels of risk taking. Such user considerations have important implications for the design of maps and mapping interfaces for emergency planning and response. The data also highlights the importance of the ‘right decision, wrong outcome problem’ inherent in decision-making under uncertainty: in individual instances, more risky decisions do not always lead to worse outcomes.  相似文献   

Evidence for herbivorous cave bears (Ursus spelaeus) in Goyet Cave,Belgium: implications for palaeodietary reconstruction of fossil bears using amino acid δ15N approaches          下载免费PDF全文

Yuichi I. Naito  Mietje Germonpré  Yoshito Chikaraishi  Naohiko Ohkouchi  Dorothée G. Drucker  Keith A. Hobson  Mark A. Edwards  Christoph Wißing  Hervé Bocherens 《第四纪科学杂志》2016,31(6):598-606

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Late Miocene increasing exhumation rates in the eastern part of the Alps – implications from low temperature thermochronology          下载免费PDF全文

Andreas Wölfler  Walter Kurz  Harald Fritz  Christoph Glotzbach  Martin Danišík 《地学学报》2016,28(5):297-305

A new set of apatite fission‐track and apatite (U–Th)/He data reveals a hitherto undated late Miocene exhumation pulse in the eastern part of the Eastern Alps. While distinct parts of the study area, including the Seckauer Tauern, have been at near surface conditions (<100 °C) since the Eocene, the neighbouring Niedere Tauern experienced enhanced cooling and exhumation in the middle Miocene and again at the late Miocene/Pliocene boundary. Middle Miocene exhumation is interpreted as a result of tectonic escape and convergence that operated simultaneously during lateral extrusion of the Eastern Alps. As the higher late Miocene/Pliocene exhumation rates are restricted to a single tectonic block, namely the Niedere Tauern, we infer a tectonic trigger that is probably related to a change in the external stress field that affected the Alps during this time.  相似文献   

Regional dynamical downscaling with CCLM over East Asia   总被引：1，自引：1，他引：0  

Dinan Wang  Christoph Menz  Thorsten Simon  Clemens Simmer  Christian Ohlwein 《Meteorology and Atmospheric Physics》2013,121(1-2):39-53

Inspired by the framework of the Coordinated Regional Climate Downscaling Experiment (CORDEX), the hindcast (1971–2000) and projection (2021–2050) simulations based on a resolution of $0.44^\circ$ over the East Asia domain are performed with the regional climate model COSMO-CLM (CCLM). The simulations are driven by ERA-40 reanalysis data and output of the global climate model ECHAM5. This is the first time that the CCLM is adapted and evaluated for the East Asia Monsoon region; the setup is considered a starting point for further improvements in this region by the CCLM community. The evaluation results show that the CCLM is able to reasonably capture the climate features in this region, especially the monsoon dynamics on small scales. However, total precipitation in the northern part of the domain, over the Tibetan Plateau, and over east Indonesia has a pronounced wet bias. The projected climate change under the A1B scenario indicates an overall annual surface temperature increase of 1–2 K, but no significant precipitation changes.  相似文献   

A simple method to hide data loggers safely in observation wells     

Lorenzen G  Sprenger C  Pekdeger A 《Ground water》2011,49(3):450-453

Submersible data loggers are widely used for groundwater monitoring, but their application often runs the risk of hardware and data loss through vandalism or theft. During a field study in India, the authors of this article experienced that well locks attract the attention of unauthorized persons and do not provide secure protection in unattended areas. To minimize the risk of losing data loggers, a cheap and simple solution has been invented to hide the instruments and associated attachments below the ground surface, inside observation wells. It relies on attaching the logger to a length of small-diameter pipe that is submerged at the bottom of the well, instead of attaching it to the top of the well. The small-diameter pipe with the logger is connected to a small bottle containing a magnet that floats on the water surface of the well and can be recovered using another bottle also with a magnet. A logger that is concealed in this way is difficult to detect and access without knowledge of the method and adequate removal tools. The system was tested and successfully applied for monitoring shallow observation wells at three field sites in Greater Delhi, India.  相似文献   

Mineral chemical study of U-bearing minerals from the Dominion Reefs,South Africa     

Ulrike Rantzsch  Christoph D. K. Gauert  Willem A. Van der Westhuizen  Isabelle Duhamel  Michel Cuney  Gerhard J. Beukes 《Mineralium Deposita》2011,46(2):187-196

The Neo-Archean Dominion Reefs (~3.06 Ga) are thin meta-conglomerate layers with concentrations of U- and Th-bearing heavy minerals higher than in the overlying Witwatersrand Reefs. Ore samples from Uranium One Africa’s Rietkuil and Dominion exploration areas near Klerksdorp, South Africa, were investigated for their mineral paragenesis, texture and mineral chemical composition. The ore and heavy mineral assemblages consist of uraninite, other uraniferous minerals, Fe sulphides, Ni–Co sulfarsenides, garnet, pyrite, pyrrhotite, monazite, zircon, chromite, magnetite and minor gold. Sub-rounded uraninite grains occur associated with the primary detrital heavy mineral paragenesis. U–Ti, U–Th minerals, pitchblende (colloform uraninite) and coffinite are of secondary, re-mobilised origin as evidenced by crystal shape and texture. Most of the uranium mineralisation is represented by detrital uraninite with up to 70.2 wt.% UO₂ and up to 9.3 wt.% ThO₂. Re-crystallised phases such as secondary pitchblende (without Th), coffinite, U–Ti and U–Th phases are related to hydrothermal overprint during low-grade metamorphism and are of minor abundance.  相似文献   

Reactive transport modelling of Cr(VI) treatment by cast iron under fast flow conditions     

Christoph Wanner  Urs EggenbergerUrs Mäder 《Applied Geochemistry》2011,26(8):1513-1523

The Cr(VI) reduction behaviour of five different types of grey cast iron shavings meant for construction of a permeable reactive barrier (PRB) in Thun, Switzerland, was investigated by performing batch and column experiments. Closed system batch experiments clearly demonstrated that the largest shavings also containing the largest spherical C inclusions, were best qualified for the PRB due to their fast Cr(VI) reduction rate. However, the column experiment performed with this type of material revealed that a complete and long term Cr(VI) treatment by the planned PRB was questionable due to the site-specific high groundwater flow velocities and the almost O₂ and CaCO₃ saturated aquifer conditions. The experimentally observed Cr(VI) breakthrough is explained as a result of a decline of reactivity provoked by a strong passivation by observed Fe hydroxides (FeOOH-polymorphs) and carbonates (calcite and aragonite).The column experiment was simulated using the reactive transport modelling code CrunchFlow. Iron cycling and intra-aqueous reactions were incorporated into a previously described reaction network in order to model the strong decline in reactivity of grey cast iron. All key parameters like aqueous species concentrations and mineralogical evolution of the column were successfully modelled. The modelling results confirmed that the observed Cr(VI) breakthrough was caused by surface passivation of the Fe shavings. Complete oxidation of the initially present mass of shavings is not predicted to occur during the expected PRB lifetime of several decades. The model seems to be robust, and it is expected that an application of the calibrated model in 2D to field sites will allow a quantitative evaluation for the performance of planned PRB’s in such environments.  相似文献   

Passive image interferometry for monitoring crustal changes with ambient seismic noise     

Christoph Sens-Schönfelder  Ulrich Wegler 《Comptes Rendus Geoscience》2011,343(8-9):639-651

The technique to retrieve Green’s functions by cross-correlation of seismic noise that is now often referred to as seismic interferometry opened the way to a completely new type of seismological observation – the continuous monitoring of changes in the subsurface medium. In this paper we review Passive image interferometry (PII) as the technique that makes use of the possibility to repeatedly retrieve Green’s functions in order to precisely infer medium changes by comparing Green’s functions that are retrieved at different times. PII is capable of identifying velocity changes below 0.1% and was applied successfully in different tectonic situations. We review three investigations of PII that demonstrate the wide range of possible applications. The first application that introduced the concept of PII in 2006 revealed hydrology related changes of subsurface velocity at Merapi volcano. The second application we present was the first noise based observation of co-seismic changes. And we finally review a recent investigation that documented velocity variations in the shallow subsurface of the moon.  相似文献