Petrogenesis of anomalous Queen Alexandra Range enstatite meteorites and their relation to enstatite chondrites,primitive enstatite achondrites,and aubrites     

Deon van Niekerk  Klaus Keil  Munir Humayun 《Meteoritics & planetary science》2014,49(3):295-312

Queen Alexandra Range (QUE) meteorite 94204 is an anomalous enstatite meteorite whose petrogenesis has been ascribed to either partial melting or impact melting. We studied the meteorite pairs QUE 94204, 97289/97348, 99059/99122/99157/99158/99387, and Yamato (Y)‐793225; these were previously suggested to represent a new grouplet. We present new data for mineral abundances, mineral chemistries, and siderophile trace element compositions (of Fe,Ni metal) in these meteorites. We find that the texture and composition of Y‐793225 are related to EL6, and that this meteorite is unrelated to the QUEs. The mineralogy and siderophile element compositions of the QUEs are consistent with petrogenesis from an enstatite chondrite precursor. We caution that potential re‐equilibration during melting and recrystallization of enstatite chondrite melt‐rocks make it unreliable to use mineral chemistries to assign a specific parent body affinity (i.e., EH or EL). The QUEs have similar mineral chemistries among themselves, while slight variations in texture and modal abundances exist between them. They are dominated by inclusion‐bearing millimeter‐sized enstatite (average En_99.1–99.5) with interstitial spaces filled predominantly by oligoclase feldspar (sometimes zoned), kamacite (Si approximately 2.4 wt%), troilite (≤2.4 wt% Ti), and cristobalite. Siderophile elements that partition compatibly between solid metal and liquid metal are not enriched like in partial melt residues Itqiy and Northwest Africa (NWA) 2526. We find that the modal compositions of the QUEs are broadly unfractionated with respect to enstatite chondrites. We conclude that a petrogenesis by impact melting, not partial melting, is most consistent with our observations.  相似文献   

The simulation of European heat waves from an ensemble of regional climate models within the EURO-CORDEX project   总被引：4，自引：1，他引：3  

Robert Vautard  Andreas Gobiet  Daniela Jacob  Michal Belda  Augustin Colette  Michel Déqué  Jesús Fernández  Markel García-Díez  Klaus Goergen  Ivan Güttler  Tomáš Halenka  Theodore Karacostas  Eleni Katragkou  Klaus Keuler  Sven Kotlarski  Stephanie Mayer  Erik van Meijgaard  Grigory Nikulin  Mirta Patarčić  John Scinocca  Stefan Sobolowski  Martin Suklitsch  Claas Teichmann  Kirsten Warrach-Sagi  Volker Wulfmeyer  Pascal Yiou 《Climate Dynamics》2013,41(9-10):2555-2575

The ability of a large ensemble of regional climate models to accurately simulate heat waves at the regional scale of Europe was evaluated. Within the EURO-CORDEX project, several state-of-the art models, including non-hydrostatic meso-scale models, were run for an extended time period (20 years) at high resolution (12 km), over a large domain allowing for the first time the simultaneous representation of atmospheric phenomena over a large range of spatial scales. Eight models were run in this configuration, and thirteen models were run at a classical resolution of 50 km. The models were driven with the same boundary conditions, the ERA-Interim re-analysis, and except for one simulation, no observations were assimilated in the inner domain. Results, which are compared with daily temperature and precipitation observations (ECA&D and E-OBS data sets) show that, even forced by the same re-analysis, the ensemble exhibits a large spread. A preliminary analysis of the sources of spread, using in particular simulations of the same model with different parameterizations, shows that the simulation of hot temperature is primarily sensitive to the convection and the microphysics schemes, which affect incoming energy and the Bowen ratio. Further, most models exhibit an overestimation of summertime temperature extremes in Mediterranean regions and an underestimation over Scandinavia. Even after bias removal, the simulated heat wave events were found to be too persistent, but a higher resolution reduced this deficiency. The amplitude of events as well as the variability beyond the 90th percentile threshold were found to be too strong in almost all simulations and increasing resolution did not generally improve this deficiency. Resolution increase was also shown to induce large-scale 90th percentile warming or cooling for some models, with beneficial or detrimental effects on the overall biases. Even though full causality cannot be established on the basis of this evaluation work, the drivers of such regional differences were shown to be linked to changes in precipitation due to resolution changes, affecting the energy partitioning. Finally, the inter-annual sequence of hot summers over central/southern Europe was found to be fairly well simulated in most experiments despite an overestimation of the number of hot days and of the variability. The accurate simulation of inter-annual variability for a few models is independent of the model bias. This indicates that internal variability of high summer temperatures should not play a major role in controlling inter-annual variability. Despite some improvements, especially along coastlines, the analyses conducted here did not allow us to generally conclude that a higher resolution is clearly beneficial for a correct representation of heat waves by regional climate models. Even though local-scale feedbacks should be better represented at high resolution, combinations of parameterizations have to be improved or adapted accordingly.  相似文献   

Effects of climate and density-dependent factors on population dynamics of the pine processionary moth in the Southern Alps   总被引：1，自引：0，他引：1  

Giovanni Tamburini  Lorenzo Marini  Klaus Hellrigl  Cristina Salvadori  Andrea Battisti 《Climatic change》2013,121(4):701-712

Forest pest populations can fluctuate dramatically in relation to climate and density-dependent factors. Although the distributional range of the pine processionary moth Thaumetopoea pityocampa (Lepidoptera Notodontidae) appears to be expanding northward and upslope with climate warming, the relative importance of climate and endogenous, density-dependent factors has not been clearly documented. We analyzed the population dynamics of the moth using long-term data from two provinces in the Southern Alps (Trento: 1990–2009, Bolzano/Bozen: 1975–2011) to evaluate the relative importance of climate and density-dependent factors as regional drivers. Both summer temperatures and rainfall significantly affected population growth rate, with different outcomes depending on the local conditions. Although previous studies indicated that low winter temperatures have negative effects on insect performance, our analyses did not show any negative effect on the population dynamics. A negative density dependent feedback with a 1-year lag emerged as the most important factor driving the population dynamics in both regions. Potential mechanisms explaining the observed negative density feedback include deterioration of host quality, increased mortality caused by pathogens, and increase of prolonged diapause as an adaptive mechanism to escape adverse conditions.  相似文献   

Dynamic analogue initialization for ensemble forecasting     

李珊  容新尧  刘赟  刘征宇 《大气科学进展》2013,30(5):1406-1420

This paper introduces a new approach for the initialization of ensemble numerical forecasting: Dynamic Analogue Initialization (DAI). DAI assumes that the best model state trajectories for the past provide the initial conditions for the best forecasts in the future. As such, DAI performs the ensemble forecast using the best analogues from a full size ensemble. As a pilot study, the Lorenz63 and Lorenz96 models were used to test DAI’s effectiveness independently. Results showed that DAI can improve the forecast significantly. Especially in lower-dimensional systems, DAI can reduce the forecast RMSE by ～50% compared to the Monte Carlo forecast (MC). This improvement is because DAI is able to recognize the direction of the analysis error through the embedding process and therefore selects those good trajectories with reduced initial error. Meanwhile, a potential improvement of DAI is also proposed, and that is to find the optimal range of embedding time based on the error’s growing speed.  相似文献   

Editorial: The Depositional Record     

Peter K. Swart  Paul A. Carling  Adrian M. Immenhauser  James S. Klaus 《Sedimentology》2014,61(6):1485-1485

  相似文献   

Satellitenbild und Meereiserkundung     

Klaus Strübing 《Ocean Dynamics》1970,23(5):193-213

  相似文献   

193nm ArF准分子激光系统对LA-ICP-MS分析中不同基体的剥蚀行为和剥蚀速率探究   总被引：7，自引：6，他引：1  

吴石头  许春雪  Klaus Simon  肖益林  王亚平 《岩矿测试》2017,36(5):451-459

探究LA-ICP-MS分析中不同基体的剥蚀行为和剥蚀速率,可为激光参数设定、基体匹配选择、数据质量保证等方面提供重要参考。本文研究了193 nm ArF准分子激光系统对人工合成/地质样品玻璃、常见矿物和粉末压片的剥蚀行为,同时探究了激光参数(束斑直径、能量密度和剥蚀频率)对剥蚀速率的影响情况。从剥蚀坑形貌可知,193nm ArF激光对玻璃和绝大多数矿物的剥蚀行为良好,但对石英相对较差,这可能与石英内含有微观包裹体,剥蚀过程中局部受热不均有关。粉末压片的剥蚀行为呈现出不可控,可通过提高粉末压片的压制压力或降低粉末颗粒的粒径来改善剥蚀行为;当剥蚀深度大于1.5倍束斑直径时,剥蚀速率随剥蚀深度的增加而逐渐减小,剥蚀深度最多可达束斑直径的两倍左右(RESOlution M-50型号激光系统,3.0 J/cm2激光能量密度);剥蚀速率随激光能量密度的增加而增大,但基本不受剥蚀频率(2~20 Hz)影响。不同基体具有特征的剥蚀速率,本文报道了43种基体的剥蚀速率参数,总体而言,NIST系列玻璃的剥蚀速率大于地质样品玻璃,碳酸盐矿物和硫化物矿物大于硅酸岩矿物,粉末压片大于玻璃和常见矿物。  相似文献   

A. BEER (Ed.): Vistas in Astronomy. Volume 15. Perganion Press,Oxford, New York,Toronto, Sidney,Braunschweig, 1973. VII + 192 Seiten,Preis E 9.00     

Klaus Frilae 《Astronomische Nachrichten》1975,296(1):46-47

  相似文献   

PATRICK MOORE: The Planet Neptun. Elis Horwood Ltd., Chichester; John Wiley & Sons,New York—Chichester—Brisbane—Toronto, 1988. 144 Seiten,Preis: £ 19,95. ISBN 0-7458-0606     

Klaus Fritze 《Astronomische Nachrichten》1989,310(6):444-444

  相似文献   

S. Böhme et al. (eds.): Astronomy and Astrophysics Abstracs. Volume 34. Literature 1983, Part 2. Published for Astronomi- sches Rechen-Institut by Springer-Verlag,Berlin-Heidelberg- New York-Tokyo. 1984. × + 921 Seitcn,Preis DM 148.-. ISBN 3-540-13485-9. ISBN 0-387-13485-9     

Klaus Frilze 《Astronomische Nachrichten》1985,306(4):261-262

  相似文献