Analytical modelling of wintertime coastal jets in the Adriatic Sea     

Martin Lazar  Marko Pavić  Zoran Pasarić  Mirko Orlić 《Continental Shelf Research》2007

Two diagnostic models, reproducing circulation generated in a marginal sea by variable density, have been developed. The models’ domain is a 2D transverse section for which analytical solutions have been obtained. They describe the winter situation in the northern Adriatic, with a strong vertical mixing present and the density maximum dominating the centre of the basin. Both models employ Boussinesq-type parametrisation of friction and linear slip at the bottom. The first model allows for frictional departure from hydrostatic equilibrium and includes vertical friction only. The second one is hydrostatic but allows for lateral friction as well. The results obtained by the two models are similar and to some extent dependent on the vertical and bottom friction. They reproduce several well known characteristics of the Adriatic circulation (cyclonic surface flow, downwelling in the central and larger part of the basin compensated by upwelling in the coastal zone) but also predict some phenomena that are still not well understood. A conspicuous feature of the model results are coastal jets, which were observed in the Adriatic on several occasions. The present models show that the distance of jets from the coasts depends on lateral friction: it is found to vary from 1 up to 10 km on the Italian side and between 2 and 15 km on the Croatian side. Both models reproduce the west–east asymmetry, with the wider current on the east side of the basin. The asymmetry is a subject on which conflicting empirical results exist in the Adriatic. In the two models cyclonic flow occupies the whole water column, which disagrees with some recent theoretical findings of the near-bottom anticyclonic flow and thus leaves the issue open.  相似文献   

An investigation of wind-driven topographically controlled motions in the Northern Adriatic     

Milivoj Kuzmić  Mirko Orlić  Muhamed Karabeg  Ljubomir Jeftić 《Estuarine, Coastal and Shelf Science》1985,21(4):481-499

The present paper describes a three-dimensional hydrodynamical numerical model of the Northern Adriatic. The model is based on the approach of N.S. Heaps in which the integral transformations are used to reproduce the vertical distribution of velocity. The model is applied to reproduce the wind-induced motion in the Northern Adriatic during winter. Hydrographic, sea level and current data collected during the MEDALPEX are used to verify the model predictions. Analysis of the empirical data suggests that the bura wind induces the most pronounced, although transient, contribution to the Northern Adriatic current field. The model predictions clearly show the controlling influence of a shallower bottom along the Italian coast. The model to data comparison suggests for the eddy viscosity coefficient value an order of magnitude lower than expected from literature data. The quadratic law for bottom friction and wind-stress curl have been identified as possible improvements of the model.  相似文献   

Spatio-temporal dynamics of suspended matter properties and bacterial communities in the back-barrier tidal flat system of Spiekeroog Island     

Andreas Lemke  Mirko Lunau  Jana Stone  Olaf Dellwig  Meinhard Simon 《Ocean Dynamics》2009,59(2):277-290

Back-barrier tidal flat systems are characterized by basins and inlets through which water is exchanged with the coastal sea by tidal water movements. The hydrographic and morphometric properties at the inlets and in the basins vary considerably, but there is little information available how biogeochemical properties in the water column at these different sites respond to these differences. Therefore, we investigated tidal dynamics of suspended particulate matter (SPM), particulate and dissolved organic carbon (DOC), chlorophyll a, phaeopigments, numbers of particle-associated (PA) and free-living bacteria (FL), bacterial biomass production, and concentrations of dissolved manganese (Mn). Samples were taken at the surface, a mid-depth and 1 m above the bottom at a fixed station at the inlet and in the basin of the Spiekeroog back-barrier tidal flat system in the German Wadden Sea. Five tidal cycles representative for typical seasonal situations, January (winter), April and May (late spring bloom), July (summer), and November (late fall) were studied in 2005 and 2006. In July, processes related to phytoplankton dynamics and bacterial decomposition were much more enhanced in the basin, whereas in April, these processes were enhanced at the inlet but were particularly low within the basin itself. The low values within the basin were a result of the settled phytoplankton spring bloom and represent a rather short period at the decline of this bloom. In November and January, differences were much less pronounced than during the growing season and restricted mainly to SPM and PA bacteria, exhibiting higher values in the basin. FL bacteria, DOC, and dissolved Mn exhibited different patterns and much less differences between the two stations, indicating that biogeochemical processes in the dissolved phase were controlled by different factors than PA biogeochemical processes. These differences reflect the retentive properties of the basin for particles and PA biogeochemical processes, particularly during the growing season, and in general emphasize the high productivity of back-barrier tidal flat systems.  相似文献   

PP/PS Wavefield separation by independent component analysis   总被引：1，自引：0，他引：1  

Mirko van der Baan 《Geophysical Journal International》2006,166(1):339-348

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The effects of sand extraction on the macrobenthos of a relict sands area (northern Adriatic Sea): results 12 months post-extraction     

Simonini R  Ansaloni I  Bonvicini Pagliai AM  Cavallini F  Iotti M  Mauri M  Montanari G  Preti M  Rinaldi A  Prevedelli D 《Marine pollution bulletin》2005,50(7):768-777

Sands for the nourishment of beaches along the Emilia-Romagna coast (northern Adriatic Sea) were dredged from an offshore area characterised by relict sands formed during the last Adriatic post-glacial transgression. The short-term effects of the sand extraction on macrozoobenthic communities were investigated before, during and 1, 6 and 12 months after dredging at three impacted stations and seven control stations. Sand extraction activities did not significantly influence the granulometry and %TOC in the sediment but caused almost complete defaunation at dredging stations. Yet, just 12 months after the extraction, the recolonisation of communities at the impacted stations was at an advanced stage. Unlike other studies on the effects of extraction of marine sand, no significant settlement of opportunistic species was observed. The limited impact of the sand extraction operation on the physical characteristics of the sediment and hydrological-sedimentary characteristics in the relict sand area should aid its rapid recovery and the restoration of the original community in a short period of time (2-4 years after dredging).  相似文献   

DISCUSSION OF "Vyredox-In Situ Purification of Ground Water," by Rolf O. Hallberg and Rudolf Martinell, March-April 1976 issue, pp. 88–93     

Mirko Riha 《Ground water》1976,14(6):481-481

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Middle Jurassic age of basalts and the post-obduction sedimentary sequence in the Guevgueli Ophiolite Complex (Republic of Macedonia)     

Duje?Kuko?Email author  ?pela?Gori?an  Adrijan?Ko?ir  Mirko?Belak  Josip?Halami?  Hazim?Hrvatovi? 《International Journal of Earth Sciences》2015,104(2):435-447

The Guevgueli Ophiolite Complex near Demir Kapija (Eastern Vardar Ophiolitic Unit) was studied for the age and facies of the overlying sediments. Cherts in direct contact with basalts are dated to late Bathonian–early Callovian with radiolarians. The post-obduction sequence, here informally named the Demir Kapija group, is composed of polymictic conglomerate, probably Kimmeridgian in age, and a more than 350-m thick carbonate succession. The carbonate succession consists of hemipelagic, slope and platform margin facies and contains algae and benthic foraminifers indicative of the Tithonian age. These new data support the previously proposed palaeogeographical connection between the Guevgueli and South Apuseni ophiolite complexes.  相似文献   

Improvements in the integration of remote sensing and rock slope modelling     

Francioni  Mirko  Salvini  Riccardo  Stead  Doug  Coggan  John 《Natural Hazards》2018,94(2):975-977

Natural Hazards - Forests are always dangerous to fire in China’s forested regions, and forest fire hazard has long been a serious issue in China. Zhejiang province is one of the key forest...  相似文献   

On the combination of global and local data in collocation theory     

Roland Pail  Mirko Reguzzoni  Fernando Sansó  Norbert Kühtreiber 《Studia Geophysica et Geodaetica》2010,54(2):195-218

Due to the successful operation of dedicated satellite gravity missions, nowadays high-accuracy global gravity field models have become available. This triggers the challenge to optimally combine this long to medium wavelength gravity field information derived from space-borne data with high-resolution terrestrial gravity data. In this paper, the least squares collocation concept is revised with the attempt to consistently unify the combination procedure in such a way that the full information contained in both data sets is merged. For example, in local or regional geoid determination the remove-restore method is usually applied only partially taking into account the accuracy of the global model coefficients used for the long-wavelength reduction. The key advantage of the extended formulation is the fact that it automatically accounts for the error covariance of all data types involved. The applicability, feasibility and performance of the proposed method is investigated in the frame of numerical closed-loop simulations. The two main fields of application, i.e., the improvement of a global gravity field model by terrestrial gravity field data, and, vice versa, the support to a regional geoid solution by the incorporation of a global gravity field model, have been analyzed and assessed. Although applied under simplified conditions, it could be shown that the method works and is practically applicable.  相似文献   

Approximate seismic risk assessment of building structures with explicit consideration of uncertainties          下载免费PDF全文

Mirko Kosič  Peter Fajfar  Matjaž Dolšek 《地震工程与结构动力学》2014,43(10):1483-1502

An approximate seismic risk assessment procedure for building structures, which involves pushover analysis that is performed utilizing a deterministic structural model and uncertainty analysis at the level of the equivalent SDOF model, is introduced. Such an approach is computationally significantly less demanding in comparison with procedures based on uncertainty analysis at the level of the entire structure, but still allows for explicit consideration of the effect of record‐to‐record variability and modelling uncertainties. A new feature of the proposed pushover‐based method is the so‐called probabilistic SDOF model. Herein, the proposed methodology is illustrated only for reinforced concrete (RC) frames, although it could be implemented in the case of any building structure, provided that an appropriate probabilistic SDOF model is available. An extensive parametric analysis has been performed within the scope of this study in order to develop a probabilistic SDOF model, which could be used for the seismic risk assessment of both code‐conforming and old, that is, non code‐conforming RC frames. Based on the results of risk analysis for the four selected examples, it is shown that the proposed procedure can provide conservative estimates of seismic risk with reasonable accuracy, in spite of the employed simplifications and the relatively small number of Monte Carlo simulations with Latin hypercube sampling, which are performed at the level of the SDOF model. An indication of the possible default values of dispersion measures for limit‐state intensities in the case of low to medium‐height RC frames is also presented. Copyright © 2014 John Wiley & Sons, Ltd.  相似文献