Synoptic survey on dissolved trace metal levels in Baltic surface waters     

Klaus Kremling  Harald Petersen 《Marine pollution bulletin》1984,15(9):329-334

A total of 95 surface water samples (6 m depth) was collected during a transect from the Bothnian Bay to Kiel between 28 August and 5 September 1982. This report presents the dissolved trace metal (<0.4 μm) and the associated hydrographic and nutrient data. Except for aluminium, all other metals determined (Zn, Cd, Cu, Ni, Fe, Mn) showed a rather homogeneous distribution within the subregions, with highest values in the Bothnian Bay (except for Mn) and net variations of the individual samples of about 20%. Cadmium, copper and nickel reveal conservative behaviour when values from this study and literature data from the Kattegat and North Sea area are plotted against salinity.  相似文献   

Book reviews     

Peter Halbach  Klaus Germann  D. D. Klemm  H. Borchert 《Mineralium Deposita》1982,17(2):307-311

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A New Method for Simultaneous Measurement of Cl⁻, Br⁻, NO₃⁻, SCN⁻, and I⁻ at Sub-ppm Levels in Ground Water     

Klaus J. Stetzenbach  Glenn M. Thompson 《Ground water》1983,21(1):36-41

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Interdecadal variability of winter precipitation in Southeast China     

Ling Zhang  Xiuhua Zhu  Klaus Fraedrich  Frank Sielmann  Xiefei Zhi 《Climate Dynamics》2014,43(7-8):2239-2248

Interdecadal variability of observed winter precipitation in Southeast China (1961–2010) is characterized by the first empirical orthogonal function of the three-monthly Standardized Precipitation Index (SPI) subjected to a 9-year running mean. For interdecadal time scales the dominating spatial modes represent monopole features involving the Arctic Oscillation (AO) and the sea surface temperature (SST) anomalies. Dynamic composite analysis (based on NCEP/NCAR reanalyzes) reveals the following results: (1) Interdecadal SPI-variations show a trend from a dryer state in the 1970s via an increase during the 1980s towards stabilization on wetter conditions commencing with the 1990s. (2) Increasing wetness in Southeast China is attributed to an abnormal anticyclone over south Japan, with northward transport of warm and humid air from the tropical Pacific to South China. (3) In mid-to-high latitudes the weakened southward flow of polar airmasses induces low-level warming over Eurasia due to stronger AO by warmer zonal temperature advection. This indicates that AO is attributed to the Southeast China precipitation increase influenced by circulation anomalies over the mid-to-high latitudes. (4) The abnormal moisture transport along the southwestern boundary of the abnormal anticyclone over south Japan is related to anomalous south-easterlies modulated by the SST anomalies over Western Pacific Ocean; a positive (negative) SST anomaly will strengthen (weaken) warm and humid air transport, leading to abundant (reduced) precipitation in Southeast China. That is both AO and SST anomalies determine the nonlinear trend observed in winter precipitation over Southeast China.  相似文献   

Low-frequency climate variability of an aquaplanet     

Eileen Hertwig  Frank Lunkeit  Klaus Fraedrich 《Theoretical and Applied Climatology》2015,121(3-4):459-478

The long-term variability of an aquaplanet climate is analyzed with a coupled atmosphere–ocean–sea ice general circulation model. The main result of the 20,000 years simulation is a very dominant low-frequency oscillation with a period of approximately 700 years. All compartments of the aquaplanet (atmosphere, ocean, and sea ice) are involved as the climate alternates between warmer and colder states. Comprehensive time series analyses, as well as a comparison between mean states of cold and warm phases, give a detailed picture of the life cycle of the low-frequency oscillation. The warm phases are characterized by ice-free polar waters and a weaker meridional overturning circulation. During cold phases, the poles are completely covered by sea ice (down to 65^° N/S) and the overturning cells in the ocean are stronger. The climate state changes throughout atmosphere and ocean; however, surface areas in high latitudes are especially affected due to the changing sea ice cover. The meridional energy transport in atmosphere and ocean alternates with the climate regime, since the ocean is more efficient in transporting heat poleward when the poles are ice-free.  相似文献   

Cyclones and their possible changes in the Arctic by the end of the twenty first century from regional climate model simulations     

Mirseid Akperov  Igor Mokhov  Annette Rinke  Klaus Dethloff  Heidrun Matthes 《Theoretical and Applied Climatology》2015,122(1-2):85-96

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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