Regional modeling of carbonaceous aerosols over Europe—focus on secondary organic aerosols     

Bertrand Bessagnet  Laurent Menut  Gabriele Curci  Alma Hodzic  Bruno Guillaume  Catherine Liousse  Sophie Moukhtar  Betty Pun  Christian Seigneur  Michaël Schulz 《Journal of Atmospheric Chemistry》2008,61(3):175-202

In this study, an improved and complete secondary organic aerosols (SOA) chemistry scheme was implemented in the CHIMERE model. The implementation of isoprene chemistry for SOA significantly improves agreement between long series of simulated and observed particulate matter concentrations. While simulated organic carbon concentrations are clearly improved at elevated sites by adding the SOA scheme, time correlation are impaired at low level sites in Portugal, Italy and Slovakia. At several sites a clear underestimation by the CHIMERE model is noticed in wintertime possibly due to missing wood burning emissions as shown in previous modeling studies. In Europe, the CHIMERE model gives yearly average SOA concentrations ranging from 0.5 μg m ^− 3 in the Northern Europe to 4 μg m ^− 3 over forested regions in Spain, France, Germany and Italy. In addition, our work suggests that during the highest fire emission periods, fires can be the dominant source of primary organic carbon over the Mediterranean Basin, but the SOA contribution from fire emissions is low. Isoprene chemistry has a strong impact on SOA formation when using current available kinetic schemes.  相似文献   

Organic matter from the Callovian (Middle Jurassic) deposits of Lithuania: Compositions,sources and depositional environments     

Leszek Marynowski  Michał Zatoń 《Applied Geochemistry》2010

This study presents the first organic geochemical and petrographical investigation of the Callovian deposits of the eastern part of the Central European Basin. It is shown that in both the terrigenous Papil? Formation (Lower Callovian) and shallow- to deeper-marine facies of the Papartin? and Skinija formations (Middle and Upper Callovian, respectively), terrestrial organic matter predominates. This is reflected by the carbon preference index values higher than 1.2 for all samples and in some cases higher than 2, as well as the occurrence of characteristic higher plant biomarkers like cadalene, dehydroabietane, simonellite and retene. Moreover, in the case of the Papil? Formation, sugiol – a natural product terpenoid produced by distinct conifer families, has been detected in clay sediments. The occurrence of such a biomolecule in the Middle Jurassic clays is reported for the first time. Its occurrence is probably connected with the presence of small wood debris in the clay sediments. In samples of the Papil? Formation, charcoal fragments co-occurring with unsubstituted polycyclic aromatic hydrocarbons were detected, indicating that wildfires took place during the Early Callovian of Lithuania and/or neighbouring areas. In the Middle and Upper marine Callovian sediments of Lithuania there is no evidence of anoxic conditions occurring in the water column. However, periodic anoxic or strongly dysoxic episodes may have occurred, most probably below the photic zone, during the deepest phase of the Late Callovian transgression, as is evidenced from pyrite framboid diameter distribution and general impoverishment of benthic fauna. Huminite reflectance (R_r) values for the investigated area are in the range of 0.21–0.31%, suggesting the occurrence of immature organic matter. Such values indicate that these investigated deposits were close to the surface during their whole diagenetic history, and the thickness of younger cover did not exceed ca. 500 m. This is also supported by a biomarker analysis in which less thermally stable ββ-hopanes and hopenes significantly dominated.  相似文献   

Geology,stratigraphy and palaeoenvironmental evolution of the Stephanorhinus kirchbergensis-bearing Quaternary palaeolake(s) of Gorzów Wielkopolski (NW Poland,Central Europe)     

Artur Sobczyk  Ryszard K. Borówka  Janusz Badura  Renata Stachowicz-Rybka  Julita Tomkowiak  Anna Hrynowiecka  Joanna Sławińska  Michał Tomczak  Mateusz Pitura  Mariusz Lamentowicz  Piotr Kołaczek  Monika Karpińska-Kołaczek  Dariusz Tarnawski  Marcin Kadej  Piotr Moska  Marek Krąpiec  Krzysztof Stachowicz  Bartosz Bieniek  Krzysztof Siedlik  Małgorzata Bąk  Jan van der Made  Adam Kotowski  Krzysztof Stefaniak 《第四纪科学杂志》2020,35(4):539-558

The sedimentary succession exposed in the Gorzów Wielkopolski area includes Eemian Interglacial (MIS 5e) or Early Weichselian (MIS 5d–e) deposits. The sedimentary sequence has been the object of intense interdisciplinary study, which has resulted in the identification of at least two palaeolake horizons. Both yielded fossil remains of large mammals, alongside pollen and plant macrofossils. All these proxies have been used to reconstruct the environmental conditions prevailing at the time of deposition, as well as to define the geological context and the biochronological position of the fauna. Optically stimulated luminescence dating of the glaciofluvial layers of the GS3 succession to 123.6 ± 10.1 (below the lower palaeolake) and 72.0 ± 5.2 ka (above the upper palaeolake) indicate that the site formed during the Middle–Late Pleistocene (MIS 6 – MIS 5). Radiocarbon-dating of the lacustrine organic matter revealed a tight cluster of Middle Pleniglacial Period (MIS 3) ages in the range of ~41–32 ka cal bp (Hengelo – Denekamp Interstadials). Holocene organic layers have also been found, with ¹⁴C ages within a range of 4330–4280 cal bp (Neolithic). Pollen and plant macrofossil records, together with sedimentological and geochemical data, confirm the dating to the Eemian Interglacial.  相似文献   

Toward very high horizontal resolution NWP over the alps: Influence of increasing model resolution on the flow pattern   总被引：1，自引：0，他引：1  

Michał Z. Ziemiański  Marcin J. Kurowski  Zbigniew P. Piotrowski  Bogdan Rosa  Oliver Fuhrer 《Acta Geophysica》2011,59(6):1205-1235

The increasing resolution of contemporary regional numerical weather prediction (NWP) models, reaching horizontal grid sizes of O(1 km), requires robust and reliable dynamical cores, working well beyond the approximation of quasi-horizontal flows. That stimulates an interest in an application for NWP purposes of dynamical cores based on the anelastic, or — more generally — sound-proof flow equations, and characterized by appropriate robustness and reliability. The paper presents results from testing the dynamical core of EULAG, the anelastic research model for multi-scale flows, as a prospective NWP dynamical core. The model simulates the semi-realistic frictionless and adiabatic flow over realistic steep Alpine topographies, employing horizontal grid sizes of 2.2, 1.1, and 0.55 km. The paper demonstrates not only the numerical robustness of EULAG, but also studies the influence of the varying horizontal resolution on the simulated flow. Results show that the increased horizontal resolution increases orographic drag on the flow. While the general flow pattern remains the same, increased resolution influences the flow on scales from hundreds of kilometers to meso-gamma scales. The differences are especially apparent in the near-surface layer of 1.5 to 3 km deep, and in the distribution and amplitudes of the orographically-induced gravity waves.  相似文献   

Testing the anelastic nonhydrostatic model EULAG as a prospective dynamical core of a numerical weather prediction model Part I: Dry benchmarks     

Bogdan Rosa  Marcin J. Kurowski  Michał Z. Ziemiański 《Acta Geophysica》2011,59(6):1236-1266

In this paper, a feasibility of anelastic approach for numerical weather prediction (NWP) is examined. The study concerns the anelastic nonhydrostatic model EULAG as a prospective candidate for the new dynamical core of a high-resolution NWP model. Such an application requires a series of benchmark tests to be performed. The study presents the results of dry idealized two-dimensional linear and non-linear tests. They include evolution of cold and warm density currents in neutrally stratified atmosphere, inertia-gravity waves in short and long channels, as well as mountain gravity waves for a set of different flow regimes. Detailed comparison of the results with the reference solutions, based mainly on the results of compressible models, indicates a high level of conformity for all of the experiments. It verifies the anelastic approach as strongly consistent with the compressible one for a broad class of atmospheric problems. It also corroborates the robustness of EULAG numerics, an essential requirement of dynamical core of NWP model.  相似文献   

A New Aerodynamic Parametrization for Real Urban Surfaces   总被引：7，自引：5，他引：2  

Manabu Kanda  Atsushi Inagaki  Takashi Miyamoto  Micha Gryschka  Siegfried Raasch 《Boundary-Layer Meteorology》2013,148(2):357-377

This study conducted large-eddy simulations (LES) of fully developed turbulent flow within and above explicitly resolved buildings in Tokyo and Nagoya, Japan. The more than 100 LES results, each covering a 1,000 $\times $ 1,000 m $^{2}$ area with 2-m resolution, provide a database of the horizontally-averaged turbulent statistics and surface drag corresponding to various urban morphologies. The vertical profiles of horizontally-averaged wind velocity mostly follow a logarithmic law even for districts with high-rise buildings, allowing estimates of aerodynamic parameters such as displacement height and roughness length using the von Karman constant $=$ 0.4. As an alternative derivation of the aerodynamic parameters, a regression of roughness length and variable Karman constant was also attempted, using a displacement height physically determined as the central height of drag action. Although both the regression methods worked, the former gives larger (smaller) values of displacement height (roughness length) by 20–25 % than the latter. The LES database clearly illustrates the essential difference in bulk flow properties between real urban surfaces and simplified arrays. The vertical profiles of horizontally-averaged momentum flux were influenced by the maximum building height and the standard deviation of building height, as well as conventional geometric parameters such as the average building height, frontal area index, and plane area index. On the basis of these investigations, a new aerodynamic parametrization of roughness length and displacement height in terms of the five geometric parameters described above was empirically proposed. The new parametrizations work well for both real urban morphologies and simplified model geometries.  相似文献   

Re–Os geochronology on sulfides from the Tudun Cu–Ni sulfide deposit,Eastern Tianshan,and its geological significance     

Minfang?WangEmail author  Wei?Wang  Jens?Gutzmer  Kun?Liu  Chao?Li  Przemys?aw?P.?Micha?ak  Qinlin?Xia  Xiaonan?Guo 《International Journal of Earth Sciences》2015,104(8):2241-2252

The Tudun deposit is a medium-sized Cu–Ni sulfide deposit, located at the westernmost edge of the Huangshan–Jing’erquan Belt in the northern part of Eastern Tianshan, NW China. Sulfide separates including pentlandite, pyrrhotite and chalcopyrite from the Tudun deposit, contain Re, common Os and ¹⁸⁷Os ranging from 40.46 to 201.2, 0.8048 to 6.246 and 0.1709 to 0.9977 ppb, respectively. They have very low ¹⁸⁷Os/¹⁸⁸Os ratios of 1.224–2.352. The sulfides yield a Re–Os isochron age of 270.0 ± 7.5 Ma (MSWD = 1.3), consistent within uncertainty with the SHRIMP zircon U–Pb age for the Tudun mafic intrusion (gabbro) of 280.0 ± 3.0 Ma. The calculated initial ¹⁸⁷Os/¹⁸⁸Os ratio is 0.533 ± 0.022, and γOs values range from 283 to 307, with a mean of 297, indicating significant crustal contamination of the parent melt prior to sulfide saturation. The Tudun deposit shares the same age and Re–Os isotopic compositions with other orthomagmatic Cu–Ni sulfide deposits in Huangshan–Jing’erquan Belt, suggesting that they have formed in Early Permian.  相似文献   

Geology,permafrost, and lake level changes as factors initiating landslides on Olkhon Island (Lake Baikal,Siberia)     

Sebastian Tyszkowski  Halina Kaczmarek  Michał Słowiński  Elena Kozyreva  Dariusz Brykała  Artiom Rybchenko  Viktoria A. Babicheva 《Landslides》2015,12(3):573-583

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Spatially distributed observations in constraining inundation modelling uncertainties     

Micha Werner  Sarka Blazkova  Jiri Petr 《水文研究》2005,19(16):3081-3096

The performance of two modelling approaches for predicting floodplain inundation is tested using observed flood extent and 26 distributed floodplain level observations for the 1997 flood event in the town of Usti nad Orlici in the Czech Republic. Although the one‐dimensional hydrodynamic model and the integrated one‐ and two‐dimensional model are shown to perform comparably against the flood extent data, the latter shows better performance against the distributed level observations. Comparable performance in predicting the extent of inundation is found to be primarily as a result of the urban reach considered, with flood extent constrained by road and railway embankments. Uncertainty in the elevation model used in both approaches is shown to have little effect on the reliability in predicting flood extent, with a greater impact on the ability in predicting the distributed level observations. These results show that reliability of flood inundation modelling in urban reaches, where flood risk assessment is of more interest than in more rural reaches, can be improved greatly if distributed observations of levels in the floodplain are used in constraining model uncertainties. Copyright © 2005 John Wiley & Sons, Ltd.  相似文献   

The Younger Dryas climatic conditions in the Za Mnichem Valley (Polish High Tatra Mountains) based on exposure‐age dating and glacier‐climate modelling     

Michał Makos  Jerzy Nitychoruk  Marek Zreda 《Boreas: An International Journal of Quaternary Research》2013,42(3):745-761

Cosmogenic ³⁶Cl was measured in bedrock and moraine boulders in the Za Mnichem Valley (High Tatra Mountains). The post‐LGM deglaciation of the study area occurred about 15.9 ka ago. The northernmost part of the valley slopes was ice‐free around 15 ka ago. The terminal moraine on the valley threshold was finally stabilized 12.5 ka ago during the Younger Dryas cold event (Greenland Stadial 1). At that time, the Za Mnichem glacier was 1.3 km long and had an area of 0.57 km². The AAR equilibrium line of the glacier was located at 1990 m a.s.l., which corresponds to an ELA depression of ～500 m compared to today. The mean summer temperature was colder by 4°–4.5°C than the present‐day temperature. The mean annual temperature was colder by 6°C than today. Such conditions suggest a decrease of the annual precipitation by ～15–25% compared with the present‐day annual average. These data indicate a probable uniform temperature change across central and western Europe, with the precipitation being the most significant factor affecting the mass balance of mountain glaciers. The spatial distribution of balance data suggests increasing continentality towards the east during the Younger Dryas.  相似文献