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Search Results: 1 - 10 of 241485 matches for " Alberto R. Piola "
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ANALYSIS OF SPACE-TIME VARIABILITY OF THE PLATA RIVER PLUME
Piola,Alberto R.; Romero,Silvia I.;
Gayana (Concepción) , 2004, DOI: 10.4067/S0717-65382004000300030
Abstract: satellite ocean colour data from the sea-viewing wide field-of-view sensor are analyzed to monitor the space-time variability of the plata river plume over the continental shelf and slope. seawifs chlorophyll-a (csat) product is used to understand the nature of changes in the colour of waters and how this relates to variations in wind direction and river outflow. we use a 5-year data set (1998-2002) of global area coverage monthly mean composites. the analysis of csat data reveals strong seasonal variability over the continental shelf with maximum northeastward penetrations in the austral winter (june to august). the plume may reach ~27s, about 1000 km northeast of the plata estuary. in summer the plume is confined to south of 32°s and the plata waters are frequently exported to the open ocean through the brazil/malvinas confluence. this seasonal shift is similar to the variation of surface salinity observed in historical hydrographic data and is presumably associated to the variable influence of the along-shore wind stress. interannually, 2002 showed the maximum northeastward penetration and the strongest anomalies (6mg/m3). from late 1999 to early 2000, a strong negative csat anomaly (<6mg/m3) within the estuary could be linked to a period of very low plata outflow (<12,000m3/seg). results suggest that csat geophysical product is a good indicator of the presence of the plata diluted waters. other case ii ocean colour products are being explored (cdom)
ANALYSIS OF SPACE-TIME VARIABILITY OF THE PLATA RIVER PLUME
Alberto R. Piola,Silvia I. Romero
Gayana (Concepción) , 2004,
Abstract: Satellite ocean colour data from the Sea-Viewing Wide Field-of-View Sensor are analyzed to monitor the space-time variability of the Plata river plume over the continental shelf and slope. SeaWiFS Chlorophyll-a (CSAT) product is used to understand the nature of changes in the colour of waters and how this relates to variations in wind direction and river outflow. We use a 5-year data set (1998-2002) of Global Area Coverage monthly mean composites. The analysis of CSAT data reveals strong seasonal variability over the continental shelf with maximum northeastward penetrations in the austral winter (June to August). The plume may reach ~27S, about 1000 km northeast of the Plata estuary. In summer the plume is confined to south of 32°S and the Plata waters are frequently exported to the open ocean through the Brazil/Malvinas Confluence. This seasonal shift is similar to the variation of surface salinity observed in historical hydrographic data and is presumably associated to the variable influence of the along-shore wind stress. Interannually, 2002 showed the maximum northeastward penetration and the strongest anomalies (6mg/m3). From late 1999 to early 2000, a strong negative CSAT anomaly (<6mg/m3) within the estuary could be linked to a period of very low Plata outflow (<12,000m3/seg). Results suggest that CSAT geophysical product is a good indicator of the presence of the Plata diluted waters. Other Case II ocean colour products are being explored (CDOM)
A numerical study of the Plata River plume along the southeastern South American continental shelf
Pimenta, Felipe M.;Campos, Edmo José Dias;Miller, Jerry L.;Piola, Alberto R.;
Brazilian Journal of Oceanography , 2005, DOI: 10.1590/S1679-87592005000200004
Abstract: the rio de la plata, one of the largest rivers on earth, discharges into the ocean waters from basin that covers a large area of south america. its plume extends along northern argentina, uruguay, and southern brazil shelves strongly influencing the ecosystems. in spite of this, little is known about the mechanisms that control it. here we report results of simulations with pom carried out to investigate the roles of wind and river discharge in plata plume dynamics. different outflows were explored, including an average climatological value and magnitudes representative of la ni?a and el ni?o. forcing the model with river discharge the average plume speed was directly related to the outflow intensity. the plata northward extension varied from 850 to 1550 km and for average discharge a band of low salinity waters formed from the estuary up to 30on of south brazilian shelf. upwelling and downwelling winds were applied after 130 days. the distribution of low salinity waters over the shelf was more sensitive to the wind direction than to the river outflow variability. downwelling winds were very capable of advecting the low salinity signal downshelf. upwelling winds were efficient in eroding the plume, which was basically detached from the coast by ekman drift. abnormal plume intrusions toward low latitudes may be a result of the original plume position coupled with events of persistent strong downwelling favorable winds.
The influence of the Brazil and Malvinas Currents on the southwestern Atlantic shelf circulation
R. P. Matano,E. D. Palma,A. R. Piola
Ocean Science Discussions (OSD) , 2010, DOI: 10.5194/osd-7-837-2010
Abstract: The oceanic circulation over the southwestern Atlantic shelf is influenced by large tidal amplitudes, substantial freshwater discharges, high wind speeds and – most importantly – by its proximity to two of the largest western boundary currents of the world ocean: the Brazil and Malvinas currents. This review article aims to describe the dynamical processes controlling the interaction between the shelf and the deep-ocean. The discussion is focused on two broad regions: the South Brazil Bight to the north, and Patagonia to the south. The exchanges between the Brazil Current and the South Brazil Bight are characterized by the intermittent development of eddies and meanders of the Brazil Current at the shelfbreak. However, it is argued that this is not the only – nor the most important – influence of the Brazil Current on the shelf. Numerical simulations show that the thermohaline structure of the South Brazil Bight can be entirely ascribed to steady state, bottom boundary layer interactions between the shelf and the Brazil Current. The Malvinas Current does not show the development of eddies and meanders, but its influence on the Patagonian shelf is no less important. Models and observations indicate that the Malvinas Current not only controls the shelfbreak dynamics and cross-shelf exchanges but also the circulation in the shelf's interior.
The influence of the Brazil and Malvinas Currents on the Southwestern Atlantic Shelf circulation
R. P. Matano,E. D. Palma,A. R. Piola
Ocean Science (OS) & Discussions (OSD) , 2010, DOI: 10.5194/os-6-983-2010
Abstract: The oceanic circulation over the southwestern Atlantic shelf is influenced by large tidal amplitudes, substantial freshwater discharges, high wind speeds and – most importantly – by its proximity to two of the largest western boundary currents of the world ocean: the Brazil and Malvinas currents. This review article aims to discriminate the dynamical processes controlling the interaction between this extensive shelf region and the deep-ocean. The discussion is focused on two broad regions: the South Brazil Bight to the north, and Patagonia to the south. The exchanges between the Brazil Current and the South Brazil Bight are characterized by the intermittent development of eddies and meanders of the Brazil Current at the shelfbreak. However, it is argued that this is not the only – nor the most important – influence of the Brazil Current on the shelf. Numerical simulations show that the thermohaline structure of the South Brazil Bight can be entirely ascribed to steady state, bottom boundary layer interactions between the shelf and the Brazil Current. The Malvinas Current does not show the development of eddies and meanders, but its influence on the Patagonian shelf is not less important. Models and observations indicate that the Malvinas Current not only controls the shelfbreak dynamics and cross-shelf exchanges but also influences the circulation in the shelf's interior.
Deliberate self poisoning'profiles in Rosario
Piola JC
RETEL : Revista de Toxicología en Línea , 2005,
Abstract: 3365 suicide attempts with toxic (or deliberate self poisoning) cases registrations attended in Sertox, Rosario, Argentina, between 1990 and 1999 are analyzed, stored in electronic format with an own software. These data are processed with a package dedicated to the exploratory analysis of numerical multidimensional data (SPAD Version 4.51). The hypothesis is that some schedules and days of occurrence of the deliberate self poisoning presented are associates with the categories of clinical pictures 'with or without symptoms'. The factorial analysis destined to study the structure of the information in their assembly is shown in a graphic and in another the classification adapts itself or cluster on factorials coordinates, cutting the tree in 7 classes or profiles. The women represent the 75.5% of the total and they are in two classes associate with asymptomatic pictures or with light symptoms. The remainder of the classes corresponds to men associate with light symptoms, moderates and serious, except in a class (without symptoms). It is confirmed that symptomatic pictures in men and women are associates to Friday, Saturday and Sunday and the asymptomatic pictures with Monday in women and Wednesday in men. Also some hours of the day, and other categories of variables, associates with pictures with or without symptoms are presented. Diverse recommendations arise, included the need to validate in a new investigation if the identifying categories could be considered as forecasts factors.
Deep Western Boundary Current transport variability in the South Atlantic: preliminary results from a pilot array at 34.5° S
C. S. Meinen,A. R. Piola,R. C. Perez,S. L. Garzoli
Ocean Science Discussions (OSD) , 2012, DOI: 10.5194/osd-9-977-2012
Abstract: The first direct estimates of the temporal variability of the absolute transport of the Deep Western Boundary Current (DWBC) at 34.5° S in the South Atlantic Ocean are obtained using just under one year of data from a line of four pressure-equipped inverted echo sounders. Hydrographic sections collected in 2009 and 2010 confirm the presence of the DWBC, one of the main deep pathways of the Meridional Overturning Circulation, based on neutral density, temperature, salinity, and oxygen values. Both observations confirm that the DWBC reconstitutes itself after breaking into eddies in the western sub-tropical Atlantic near 8° S. The amplitude and spectral character of the DWBC transport variability are comparable with those observed at 26.5° N, where longer records exist, with the DWBC at 34.5° S exhibiting a transport standard deviation of 25 Sv and variations of ~40 Sv occurring within periods as short as a few days. There is little indication of an annual cycle in the DWBC transports, although the observation record is too short to be definitive, and the dominant time scale during the first year of the experiment was about 9–10 days. A "Monte Carlo-style" analysis using 27 yr of model output from the same location as the observations indicates that another 48–60 months of data will be required to encompass a fairly complete span of deep transport variability. The model suggests the presence of an annual cycle in DWBC transport, however the statistical significance of the annual cycle with even 27 yr of model output is low, suggesting that annual period variations in the model are weak as well.
Deep Western Boundary Current transport variability in the South Atlantic: preliminary results from a pilot array at 34.5° S
C. S. Meinen,A. R. Piola,R. C. Perez,S. L. Garzoli
Ocean Science (OS) & Discussions (OSD) , 2012, DOI: 10.5194/os-8-1041-2012
Abstract: The first direct estimates of the temporal variability of the absolute transport in the Deep Western Boundary Current (DWBC) at 34.5° S in the South Atlantic Ocean are obtained using just under one year of data from a line of four pressure-equipped inverted echo sounders. Hydrographic sections collected in 2009 and 2010 confirm, based on neutral density, temperature, salinity, and oxygen values, the presence of the DWBC, one of the main deep pathways of the Meridional Overturning Circulation. Both data sets indicate that the DWBC reconstitutes itself after breaking into eddies in the western sub-tropical Atlantic near 8° S. The amplitude and spectral character of the DWBC transport variability are comparable with those observed in the North Atlantic, where longer records exist, with the DWBC at 34.5° S exhibiting a transport standard deviation of 25 Sv and variations of ~ 40 Sv occurring within periods as short as a few days. There is little indication of an annual cycle in the DWBC transports, although the observational records are too short to be definitive. A Monte Carlo-style analysis using 27 yr of model output from the same location as the observations indicates that about 48–60 months of data will be required to fully assess the deep transport variability. The model suggests the presence of an annual cycle in DWBC transport, however its statistical significance with even 27 yr of model output is low, suggesting that seasonal variations in the model are weak.
Malvinas-slope water intrusions on the northern Patagonia continental shelf
A. R. Piola,N. M. Avellaneda,R. A. Guerrero,F. P. Jardón
Ocean Science Discussions (OSD) , 2009,
Abstract: The Patagonia continental shelf located off southeastern South America is bounded offshore by the Malvinas Current, which extends northward from northern Drake Passage (~55° S) to nearly 38° S. The transition between relatively warm-fresh shelf waters and Subantarctic Waters from the western boundary current is characterized by a thermohaline front extending nearly 2500 km. We use satellite derived sea surface temperature, and chlorophyll-a data combined with hydrographic and surface drifter data to document the intrusions of slope waters onto the continental shelf near 41° S. These intrusions create vertically coherent localized negative temperature and positive salinity anomalies extending onshore about 150 km from the shelf break. The region is associated with a center of action of the first mode of non-seasonal sea surface temperature variability and also relatively high chlorophyll-a variability, suggesting that the intrusions are important in promoting the local development of phytoplankton. The generation of slope water penetrations at this location may be triggered by the inshore excursion of the 100 m isobath, which appears to steer the Malvinas Current waters over the outer shelf.
Political Change in Jalisco, Mexico  [PDF]
Alberto Arellano Ríos
Open Journal of Political Science (OJPS) , 2015, DOI: 10.4236/ojps.2015.51004
Abstract: This paper analyzes the political change in Jalisco, Mexico. It is a panoramic work that evaluates a democratic transition at the subnational level. The work focuses on the structures of authority of the local political regime. The analytical framework used is the one proposed by Leonardo Morlino. It analyzes the document and describes the political and institutional framework of the governments divided and unified, the relationship between the powers, among other aspects.
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