Chlorofluoromethanes in the western Indian sector of the Southern Ocean and their relations with geochemical tracers     

F. Mantisi  C. Beauverger  A. Poisson  N. Metzl 《Marine Chemistry》1991,35(1-4)

The first vertical profiles of chlorofluoromethanes (Freons F11 and F12) measured during the austral summer 1987 (INDIGO-3 cruise) in the region of Enderby Land (30°E) and the Princess Elizabeth Trough (90°E) arc presented in relation to hydrological and geochemical characteristics. In the open ocean, transient tracer penetration reaches 1000 m. Off the West Ice Shelf and Enderby Land, a significant decrease in Freons is found below the cold Winter Water and just above the deep oxygen minimum and temperature maximum of the upper Circumpolar Deep Water (200–400 m). In the region off MacRobertson Land, where the oxygen minimum is deeper (1000 m), the Freon gradients are less abrupt. In deep open ocean waters, no Freons were detected in the core of the Circumpolar Deep Water. However, near the continental shelf, we have encountered Freon minima associated with salinity maxima, indicating significant mixing between deep and (recent) ventilated waters. Over the whole water column, a strong zonal contrast emerges in tracer distributions between stations situated to the east and to the west of MacRobertson Land (65°E), which may be associated with the Weddell Gyre extension. Freon maxima associated with oxygen maxima and temperature and salinity minima that characterize Antarctic Bottom Water (AABW) have been found over all the region studied; the tracers indicate three main bottom waters that are related to Weddell Sea, Ross Sea and local origins. At two stations located on the edge of the continental shelf, Freon measurements suggest that the AABW formation was recent, and the tracers' continuity reveals a preferential westward flow of bottom waters. Although it is clear that bottom water formation takes place around 60–70°E, the information is too sparse to specify the source regions.  相似文献   

Temperature dependence of CO₂ fugacity in seawater     

Catherine Goyet  Frank J. Millero  Alain Poisson  Deborah K. Shafer 《Marine Chemistry》1993,44(2-4)

Ideally, the correction of the measured CO₂ fugacity (fCO₂) at temperature T_m to fCO₂ at the in-situ temperature T_in should be made by using at least 2 known parameters (pH-A_T, C_T-A_T,…) and the reliable constants for carbonic acid. In practice however, a measured CO₂ property pair is not always available. When fCO₂ is measured alone, one must make an estimate of the effect of temperature on seawater fCO₂ from the accurate knowledge of seawater salinity and temperature and the approximate knowledge of the carbonate parameters. In this paper we present an empirical relationship that can be used to estimate the effect of temperature on fCO₂. The equation is of the form: where fCO_2[t] and fCO_2[20] represent fCO₂ at temperatures t°C and 20°C, respectively; the parameters A, B, etc. are functions of the ratio X = C_T/A_T: where the parameters a_i, b_i, etc. are functions of salinity.The 25-parameter equation is fitted by the values of fCO₂ calculated using the constants of Goyet and Poisson (1989), when X varies from 0.8 to 1.0, t varies from −1dgC to 40°C, and S varies from 30 to 40. For T_m - T_in within ± 10°C, direct measurements of fCO₂ as a function of the temperature (from −I to 30°C verify this equation within less than ±5 μatm.  相似文献   

Population Abundances, Tidal Movement, Burrowing Ability and Oxygen Uptake of Emerita analoga (Stimpson) (Crustacea, Anomura) on a Sandy Beach of South-Central Chile     

Mariano Lastra  Eduardo Jaramillo  Jesús López  Heraldo Contreras  Cristián Duarte  & J. Germán Rodríguez 《Marine Ecology》2004,25(1):71-89

Abstract. Field sampling and other experiments were carried out during February 2001 to determine whether different morphodynamic characteristics occurring within an intermediate sandy beach of southern Chile (ca. 39°S) convey differences in population abundance, tidal movement, burrowing ability and oxygen uptake of the anomuran crab Emerita analoga (Stimpson, 1857). Crabs were collected along transects extended between the lowest swash levels and the retention zone above the effluent line of the south and north end of the beach. Burrowing times of nearly 70 crabs collected at each study site were measured in saturated sands collected from the lowest swash level of each site. Oxygen uptake of crabs was measured in incubation glass bottles. The intertidal zone of the north end of the beach was wider (56 m) and flatter (1/14) than that of the south end (45 m and 1/9, respectively). In general, the swash zone of the north end was significantly wider than the south end throughout the sampling period. The frequency of swashes and number of swash crossings above the effluent line, plus up‐wash speed, were usually higher at the steeper south end of the beach. The mean population abundance of E. analoga per linear metre of beach was significantly higher at the north end, whereas density per square metre was significantly higher at the south end. No differences were found in biomass figures. Although the highest abundance of crabs at the north end was usually observed at the lowest swash levels, similar population abundances occurred along all the tidal levels sampled at the south end. Burrowing times of crabs collected from both ends of the beach increased significantly with increasing carapace length and body mass. The mean burrowing time of crabs collected at the south end of the beach was shorter than that of those collected at the north end. Oxygen uptake of E. analoga was positively and exponentially correlated with the size of individuals collected from both ends of the beach. Results of ANCOVA showed no significant difference between the regression lines obtained for the oxygen uptake of crabs collected at both ends of the beach. It is concluded that physical features of each end of the beach seem not to differ enough to produce differences in oxygen uptake of E. analoga, or in the biomass, population structure and body size of crabs, within a single beach of south‐central Chile.  相似文献   

Recruitment indices of European hake, Merluccius merluccius (Linnaeus 1758), in the Northwest Mediterranean based on landings from bottom-trawl multispecies fisheries     

Goni  Raquel; Adlerstein  Sara; Alvarez  Federico; Garcia  Mariano; Sanchez  Pilar; Sbrana  Mario; Maynou  Francesc; Viva  Claudio 《ICES Journal of Marine Science》2004,61(5):760-773

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A note on the SG(<Emphasis Type="Italic">m</Emphasis>) test     

Fernando A. López  Mariano Matilla-García  Jesús Mur  Antonio Páez  Manuel Ruiz 《Journal of Geographical Systems》2016,18(1):87-96

López et al. (Reg Sci Urban Econ 40(2–3):106–115, 2010) introduce a nonparametric test of spatial dependence, called SG(m). The test is claimed to be consistent and asymptotically Chi-square distributed. Elsinger (Reg Sci Urban Econ 43(5):838–840, 2013) raises doubts about the two properties. Using a particular counterexample, he shows that the asymptotic distribution of the SG(m) test may be far from the Chi-square family; the property of consistency is also questioned. In this note, the authors want to clarify the properties of the SG(m) test. We argue that the cause of the conflict is in the specification of the symbolization map. The discrepancies can be solved by adjusting some of the definitions made in the original paper. Moreover, we introduce a permutational bootstrapped version of the SG(m) test, which is powerful and robust to the underlying statistical assumptions. This bootstrapped version may be very useful in an applied context.  相似文献   

Heat-producing Elements-enriched Continental Mantle Lithosphere and Proterozoic Intracontinental Orogens: Insights from Brasiliano/Pan-African Belts     

Srgio Pacheco Neves  Gorki Mariano 《Gondwana Research》2004,7(2):427-436

Collisional and accretionary processes have been recognized in several Precambrian orogens, but the formation of intracontinental (ensialic) orogens has remained elusive. The recognition that modern orogenic belts (as, for example, the mountain belts of central Asia) may form in response to far-field stresses transmitted to the interior of continental plates removed much of the objection against Proterozoic intracontinental deformation. However, the causes responsible for the localization of contractional deformation are still uncertain. Due to the strong dependence of lithosphere rheology on temperature, lithospheric thermal weakening prior to contraction must be a required condition. Studies of dioritic rocks from Borborema Province, northeastern Brazil, and Damara belt, southern Africa, indicate that they are derived from ancient, incompatible elements-enriched subcontinental lithosphere. The concentrations of the heat-producing elements K (0.6 wt %), U (0.02–0.2 ppm) and Th (0.15–1.5 ppm) estimated for this source allow calculations of heat production between 0.09 and 0.25 mW m⁻³. These high values of heat generation may cause increases in temperature of several tens to three hundred degrees Celsius with respect to cratonic mantle lithosphere, leading to great reductions in lithosphere strength. Consequently, continental domains underlain by hot and weak continental mantle may thicken under the action of relatively feeble tectonic forces. High rheological contrasts between these domains and adjacent stiff and cold blocks provide an explanation for formation of intracontinental orogens.  相似文献   

Flood Events of Selected European Rivers in the Sixteenth Century     

Rudolf Brázdil  Rüdiger Glaser  Christian Pfister  Petr Dobrovolný  Jean-Marc Antoine  Mariano Barriendos  Dario Camuffo  Mathias Deutsch  Silvia Enzi  Emanuela Guidoboni  Oldřich Kotyza  Fernando Sanchez Rodrigo 《Climatic change》1999,43(1):239-285

The severity and frequency of sixteenth-century floods of the Rhine, the Main, the middle and upper Elbe with its tributaries, rivers of northern and central Italy, the Garonne and rivers in Catalonia and Andalusia are analyzed using documentary evidence. The basic topographical and hydrological characteristics of the rivers investigated as well as the synoptic causes of their flooding during the instrumental period are presented. Different examples of modifications of the run-off process due to anthropogenic activity are discussed. Prevalence in flood occurrence during the second half of the sixteenth century in comparison to the first half is typical for central European and Andalusian rivers (mainly in the 1560s and 1590s) and agrees with the evolution of precipitation patterns. On the other hand, Italian and Catalonian rivers, in part, had a higher occurrence of floods during the first half of the century. Changes in the flooding seasons in both halves of the century are not unambiguous. Results of an analysis on a broader European scale show floods to be a random natural phenomena with limited areal extent defined by the spatial influence of forcing meteorological factors (continuous heavy rains, sudden melting of thick snow cover, etc.). Despite some limitations of documentary evidence, series of reconstructed historical floods are valuable sources of proxy data which can be utilized for the study of the flooding fluctuations in the pre-instrumental period.  相似文献   

A method for solving the planetary boundary-layer equations   总被引：1，自引：0，他引：1  

Mariano A. Estoque  Chandrakant M. Bhumralkar 《Boundary-Layer Meteorology》1970,1(2):169-194

A method for solving the nonlinear three-dimensional steady-state equations which govern planetary boundary layer flow is described. The method is applicable to air motions over terrain with horizontally varying surface roughness, temperature and moisture. It can also be applied to a physical system consisting of the air and the sea (or earth) boundary layers taken together. Examples of calculations for selected cases of terrain variations are presented. Convergence of the method has been assessed by determining the degree to which the solutions satisfy the set of equations.The results of the calculations show that the method produces qualitatively realistic distributions of the different meteorological variables.Contribution No. 1251 from the University of Miami, Rosenstiel School of Marine and Atmospheric Sciences.  相似文献   

Probabilistic seismic hazard assessment in SE-Spain based on macroseismic site histories     

Maria-Jose Jiménez  Dario Albarello  Mariano García-Fernández 《Bulletin of Earthquake Engineering》2016,14(7):1849-1867

In many countries such as Spain earthquake databases still mainly comprise macroseismic data from felt effects. The full exploit of this information is of basic importance for seismic risk assessment and emergency planning, given the strict link between macroseismic intensity and damage. A probabilistic procedure specifically developed to handle macroseismic data, mostly relying on site information and seismogenic-source free, has been applied to evaluate seismic hazard in SE-Spain (Alicante-Murcia region). Present seismicity is moderate-low with largest magnitudes slightly over Mw5.0. The historical record includes very destructive earthquakes, maximum EMS98 intensities reaching IX–X and X in the nineteenth century (e.g., Torrevieja 1829 earthquake). Very recently, two events in the area on 11 May 2011 (Mw4.5, Mw5.2) killed nine people, injured 300, and produced important damage in the city of Lorca. Regional hazard maps for the area together with specific hazard curves at selected localities are obtained. Results are compared with the maximum observed intensities in the period 1300–2012, and with the values in the seismic hazard map from the Spanish Building Code in force. In general, the maximum felt intensity values are closer to the hazard values calculated for 2 % probability of exceedance in 50 years, using felt and expected intensity. The intensity-based probabilistic hazard maps obtained through the applied approach reduce the inherent smoothing of those based on standard probabilistic seismic hazard assessment approaches for the region, allowing identifying possible over- or sub-estimates of site hazard values, providing very valuable information for risk reduction strategies or for future updates of the building code hazard maps.  相似文献   

Uptake of hazardous elements by spring onion (<Emphasis Type="Italic">Allium fistulosum</Emphasis> L.) from soil irrigated with different types of water and possible health risk     

Kafeel Ahmad  Zafar Iqbal Khan  Asma Ashfaq  Muhammad Ashraf  Nudrat Aisha Akram  Muhammad Sher  Hazoor Ahmad Shad  Vincenzo Tufarelli  Antonio Lonigro  Mariano Fracchiolla  Eugenio Cazzato 《Environmental Earth Sciences》2017,76(8):322

Bio-concentration of elements such as Mo, As, Se, Fe, Cu, Zn, Ni and Pb was analyzed in spring onion (Allium fistulosum L.) in three different locations of central Punjab, Pakistan. At location GW, relatively low level of hazardous elements was found in spring onion, suggesting that groundwater is a safe source of water for irrigating food crops. The pH of soil at wastewater irrigation was found less acidic (pH 7.4) than the other sites. The range of concentration in the different samples of spring onion was as follows: 6.15–8.16 mg kg^?1 for Mo, 2.77–4.28 mg kg^?1 for As, 0.395–0.705 mg kg^?1 for Se, 36.73–48.17 mg kg^?1 for Fe, 10.58–16.26 mg kg^?1 for Cu, 28.87–39.79 mg kg^?1 for Zn, 6.66–8.75 mg kg^?1 for Ni and 4.33–6.09 mg kg^?1 for Pb, respectively. High bio-concentration of Zn (15.37) from soil to spring onion was found at canal water irrigated location. The estimated daily intake of metal for spring onion was less, but the health risk index was higher than 1 for Mo, As, Cu, Pb and Ni, respectively. This was due to higher proportion of spring onion in diet, which consequently increased the health risk index for metals. Therefore, it is recommended to avoid growing vegetables in untreated urban and rural wastewater containing elevated amounts of metals.  相似文献