A Surface-Layer Study of the Transport and Dissipation of Turbulent Kinetic Energy and the Variances of Temperature,Humidity and CO$$_$$     

João A. Hackerott  Mostafa Bakhoday Paskyabi  Joachim Reuder  Amauri P. de Oliveira  Stephan T. Kral  Edson P. Marques Filho  Michel dos Santos Mesquita  Ricardo de Camargo 《Boundary-Layer Meteorology》2017,165(2):211-231

We discuss scalar similarities and dissimilarities based on analysis of the dissipation terms in the variance budget equations, considering the turbulent kinetic energy and the variances of temperature, specific humidity and specific CO\(_2\) content. For this purpose, 124 high-frequency sampled segments are selected from the Boundary Layer Late Afternoon and Sunset Turbulence experiment. The consequences of dissipation similarity in the variance transport are also discussed and quantified. The results show that, for the convective atmospheric surface layer, the non-dimensional dissipation terms can be expressed in the framework of Monin–Obukhov similarity theory and are independent of whether the variable is temperature or moisture. The scalar similarity in the dissipation term implies that the characteristic scales of the atmospheric surface layer can be estimated from the respective rate of variance dissipation, the characteristic scale of temperature, and the dissipation rate of temperature variance.  相似文献   

Provenance and tectonic implications of Orán Group foreland basin sediments,Río Iruya canyon,NW Argentina (23° S)          下载免费PDF全文

William H. Amidon  Lisa V. Luna  G. Burch Fisher  Douglas W. Burbank  Andrew R. C. Kylander‐Clark  Ricardo Alonso 《Basin Research》2017,29(Z1):96-112

Foreland basins are important recorders of tectonic and climatic processes in evolving mountain ranges. The Río Iruya canyon of NW Argentina (23° S) exposes ca. 7500 m of Orán Group foreland basin sediments, spanning over 8 Myr of near continuous deposition in the Central Andes. This study presents a record of sedimentary provenance for the Iruya Section in the context of a revised stratigraphic chronology. We use U‐Pb zircon ages from six interbedded ash layers and new magnetostratigraphy to constrain depositional ages in the section between 1.94 and 6.49 Ma, giving an average sedimentation rate of 0.93 ± 0.02 (2σ) km Myr^?1. We then pair U‐Pb detrital zircon dating with quartz trace‐element analysis to track changes in sedimentary provenance from ca. 7.6 to 1.8 Ma. Results suggest that from ca. 7.6 to ca. 6.3 Ma, the Iruya watershed did not tap the Salta Group or Neogene volcanics that are currently exposed in the eastern Cordillera and Puna margin. One explanation is that a long‐lived topographic barrier separated the eastern Puna from the foreland for much of the mid‐late Miocene, and that the arrival of Jurassic‐Neogene zircons records regional tectonic reactivation at ca. 6.3 Ma. A second major provenance shift at ca. 4 Ma is marked by changes in the zircon and quartz populations, which appear to be derived from a restricted source region in Proterozoic‐Ordovician meta‐sediments. Considered in conjunction with the onset of coarse conglomerate deposition, we attribute this shift to accelerated uplift of the Santa Victoria range, which currently defines the catchment's western limit. A third shift at ca. 2.3 Ma records an apparent disconnection of the Iruya with the eastern Puna, perhaps due to defeat of the proto Rio‐Iruya by the rising Santa Victoria range. This study is one of the first applications of quartz trace‐element provenance analysis, which we show to be an effective complement to U‐Pb detrital zircon dating when appropriate statistical methods are applied.  相似文献   

Hydrodynamic behaviour of compacted granite sawdust from the dimension stone industry of Pontevedra (Spain): experimental and modelling     

Ismael Falcon-Suarez  Ricardo Juncosa-Rivera  Phil Vardon  Dieter Rammlmair  Thomas Günter  Ulla Noell  Jordi Delgado-Martín 《Environmental Earth Sciences》2016,75(5):421

  相似文献   

Assessment of two techniques to merge ground-based and TRMM rainfall measurements: a case study about Brazilian Amazon Rainforest     

Pedro Mateus  Laura S. Borma  Ricardo D. da Silva  Giovanni Nico  João Catalão 《地理信息系统科学与遥感》2016,53(6):689-706

The availability of accurate rainfall data with high spatial resolution, especially in vast watersheds with low density of ground-measurements, is critical for planning and management of water resources and can increase the quality of the hydrological modeling predictions. In this study, we used two classical methods: the optimal interpolation and the successive correction method (SCM), for merging ground-measurements and satellite rainfall estimates. Cressman and Barnes schemes have been used in the SCM in order to define the error covariance matrices. The correction of bias in satellite rainfall data has been assessed by using four different algorithms: (1) the mean bias correction, (2) the regression equation, (3) the distribution transformation, and (4) the spatial transformation. The satellite rainfall data were provided by the Tropical Rainfall Measuring Mission, over the Brazilian Amazon Rainforest. Performances of the two merging data techniques are compared, qualitatively, by visual inspection and quantitatively, by a statistical analysis, collected from January 1999 to December 2010. The computation of the statistical indices shows that the SCM, with the Cressman scheme, provides slightly better results.  相似文献   

Heterogeneous deformation and texture development in halite polycrystals: comparison of different modeling approaches and experimental data     

Ricardo A. Lebensohn  Paul R. Dawson  Hartmut M. Kern  Hans-Rudolf Wenk   《Tectonophysics》2003,370(1-4):287-311

Modeling the plastic deformation and texture evolution in halite is challenging due to its high plastic anisotropy at the single crystal level and to the influence this exerts on the heterogeneity of deformation over halite polycrystals. Three different assumptions for averaging the single crystal responses over the polycrystal were used: a Taylor hypothesis, a self-consistent viscoplastic model, and a finite element methodology. The three modeling approaches employ the same single crystal relations, but construct the polycrystal response differently. The results are compared with experimental data for extension at two temperatures: 20 and 100 °C. These comparisons provide new insights of how the interplay of compatibility and local equilibrium affects the overall plastic behavior and the texture development in highly anisotropic polycrystalline materials. Neither formulation is able to completely simulate the texture development of halite polycrystals while, at the same time, giving sound predictions of microstructural evolution. Results obtained using the finite element methodology are promising, although they point to the need for greater resolution of the individual crystals to capture the full impact of deformation heterogeneities.  相似文献   

Theoretical model for the formation of ion-pairs in seawater     

Dana R. Kester  Ricardo M. Pytkowicz   《Marine Chemistry》1975,3(4):365-374

Predictions of association constants for ion-pair formation in seawater were compared to measured constants as a test for the existence of ion-pairs. A fair agreement was obtained in most cases, although the theoretical electrostatic calculations indicate that significant chloride ion-pairing should occur which has not been observed in most experimental investigations.  相似文献   

Metal distributions and their fluxes at the coastal boundary of a semi-enclosed ria     

Antonio Cobelo-García  Ricardo Prego  Maite DeCastro 《Marine Chemistry》2005,97(3-4):277-292

Water column samples have been collected in the outer channel of the Ferrol Ria (NW Spain) during four occasions over a tidal cycle. The objective was to study the exchange of dissolved and particulate Cd, Cu, Pb and Zn and particulate Al, Fe and Si between the ria and the adjacent coastal waters. This study provides the first extensive dataset on dissolved and particulate metal concentrations in the water column of a Galician ria. Typical concentrations of dissolved Cd (96 ± 31 pM), Cu (8 ± 4 nM), Pb (270 ± 170 pM) and Zn (21 ± 10 nM) were similar than in other European Atlantic shelf and coastal waters. The fraction of metals in the particulate phase followed the trend: Pb > Cu Zn > Cd. The outgoing water from the ria was enriched in dissolved and particulate Cu, Pb and Zn compared with incoming waters, whereas Cd concentrations were similar for both waters. The suspended particulate matter was composed of a mixture of marine and continental material. The latter end-member was found to arise from the metal-rich ria bed sediments, which is diluted by the dominant metal-poor marine end-member. The net output flux of Cu from the channel is balanced by the freshwater inputs to the ria, and the net Zn flux gave a positive output to coastal waters. For Pb, the net flux to the coastal waters is less than that input from the rivers, as a result of its particle reactivity and deposition in sediments. On the contrary, a net input flux of dissolved Cd from coastal waters was observed, highlighting the oceanic source of this metal in the Galician rias. Results from the budget calculations are in agreement with the differential geochemical behavior of these elements in coastal waters.  相似文献   

Free vibration of rectangular plates with circular openings     

Ricardo O. Grossi  Blanca del V. Arenas  P.A.A. Laura 《Ocean Engineering》1997,24(1):19-24

The optimized Rayleigh-Ritz method is applied to generate values of the fundamental frequency coefficient and the one corresponding to the first fully antisymmetric mode for rectangular plates elastically restrained against rotation and with located circular holes. The results of this study are compared with existing data and the agreement is quite good.  相似文献   

Living macromolluscs from a paleo-reef region on the northeastern Venezuelan continental shelf     

Joaquín Buitrago  Juan Capelo  Javier Gutirrez  Martín Rada  Ricardo Hernndez  Sylvia Grune 《Estuarine, Coastal and Shelf Science》2006,66(3-4):634-642

Drowned reefs, fossil reefs or paleo-reefs, are important ecologically as areas of high biodiversity, foraging, shelter environment, and as areas supporting the spawning aggregations of economically important reef fish species. This is particularly significant when the structures are situated in a wide soft-bottom continental shelf. The presence of limestone structures, fossil reefs and pinnacles dating from circa 8 to 9 ka, to the north of the Paria Peninsula in north-eastern Venezuela, has been known to local fishermen for decades. Using echograms obtained during acoustic fisheries evaluations and the scarce previously available information, an improved location map of hard-bottom structures was made. Benthic samples to study macromolluscs were taken at depths between 54 and 93 m using an unmodified 2-m beam trawl. Four trawl samples were located over fossil reef areas while another four were situated in soft-bottom valleys between limestone structures. Fossil reefs in the area showed a highly patchy distribution. A total of 91 species from 43 Bivalvia, Gastropoda and Scaphopoda families were found, Gastropoda being the dominant class with 49 species. Paleo-reef-covered areas showed higher species richness and only 21% of the species found were common to both substrates. Gastropods Tonna maculosa and Polystira albida were the most abundant species and occurred in both substrate types. Bivalve life habits, a mixture of organism–substrate relationships, shell fixation, mobility and feeding type, differed significantly according to bottom type. Six species are recorded for the first time for eastern Venezuelan waters. Bottom heterogeneity plays an important role in marine ecosystems, providing shelter to fish populations and may be significant as breeding and nursery areas. Its presence in a region with biogeographical interest, situated in the confluence of three major provinces and with oceanographic conditions varying seasonally from upwelling dominated to Orinoco River discharges, makes this the area of interest and it should be evaluated as a possible Marine Protected Area.  相似文献   

Sulphate complexation in seawater — a short comment     

Ricardo M. Pytkowicz 《Marine Chemistry》1975,3(1):79-80

  相似文献