scholarly journals Different approaches to model the nearshore circulation in the south shore of O'ahu, Hawaii

Ocean Science ◽  
2017 ◽  
Vol 13 (1) ◽  
pp. 31-46
Author(s):  
Joao Marcos Azevedo Correia de Souza ◽  
Brian Powell
Keyword(s):  
Circulation Model ◽  
Trade Wind ◽  
The South ◽  
Regional Ocean Modeling System ◽  
Forced Circulation ◽  
Dynamical Interaction ◽  
Nearshore Circulation ◽  
South Shore ◽  
Circulation Modeling ◽  
The Waves

Abstract. The dynamical interaction between currents, bathymetry, waves, and estuarine outflow has significant impacts on the surf zone. We investigate the impacts of two strategies to include the effect of surface gravity waves on an ocean circulation model of the south shore of O'ahu, Hawaii. This area provides an ideal laboratory for the development of nearshore circulation modeling systems for reef-protected coastlines. We use two numerical models for circulation and waves: Regional Ocean Modeling System (ROMS) and Simulating Waves Nearshore (SWAN) model, respectively. The circulation model is nested within larger-scale models that capture the tidal, regional, and wind-forced circulation of the Hawaiian archipelago. Two strategies are explored for circulation modeling: forcing by the output of the wave model and online, two-way coupling of the circulation and wave models. In addition, the circulation model alone provides the reference for the circulation without the effect of the waves. These strategies are applied to two experiments: (1) typical trade-wind conditions that are frequent during summer months, and (2) the arrival of a large winter swell that wraps around the island. The results show the importance of considering the effect of the waves on the circulation and, particularly, the circulation–wave coupled processes. Both approaches show a similar nearshore circulation pattern, with the presence of an offshore current in the middle beaches of Waikiki. Although the pattern of the offshore circulation remains the same, the coupled waves and circulation produce larger significant wave heights ( ≈  10 %) and the formation of strong alongshore and cross-shore currents ( ≈  1 m s−1).

scholarly journals Different approaches to model the nearshore circulation in the south shore of Oahu, Hawaii

2016 ◽  
Author(s):  
Joao Marcos Azevedo Correia de Souza ◽  
Brian Powell
Keyword(s):  
Circulation Model ◽  
Trade Wind ◽  
The South ◽  
Regional Ocean Modeling System ◽  
Forced Circulation ◽  
Dynamical Interaction ◽  
Nearshore Circulation ◽  
South Shore ◽  
Circulation Modeling ◽  
The Waves

Abstract. The dynamical interaction between currents, bathymetry, waves, and estuarian outflow have significant impacts on the surf-zone. We investigate the impacts of two strategies to include the effect of surface gravity waves on an ocean circulation model of the south shore of O'ahu, Hawaii. This area provides an ideal laboratory for the development of nearshore circulation modeling systems for reef protected coastlines. We use two numerical models for circulation and waves: Regional Ocean Modeling System (ROMS) and Simulating Waves Nearshore (SWAN), respectively. The circulation model is nested within larger-scale models that capture the tidal, regional, and wind-forced circulation of the Hawaiian archipelago. Two strategies are explored for circulation modeling: forcing by the output of the wave model and online, two-way coupling of the circulation and wave models. In addition, the circulation model alone provides the reference for the circulation without the effect of the waves. These strategies are applied to two experiments: (1) typical trade-wind conditions that are frequent during summer months, and (2) the arrival of a large winter swell that wraps around the island. The results show the importance of considering the effect of the waves on the circulation and, particularly, the circulation-wave coupled processes. Both approaches show a similar nearshore circulation pattern, with the presence of an offshore current in the middle beaches of Waikiki. Although the pattern of the offshore circulation remains the same, the coupled waves and circulation produce larger significant wave heights (10 % to 20 %) and the formation of strong along- and cross-shore currents (~ 1 m s−1).

Combining gliders and models to understand mesoscale biogeochemical patterns at the Angola-Benguela front

2021 ◽  
Author(s):  
Elisa Lovecchio ◽  
Stephanie Henson ◽  
Filipa Carvalho ◽  
Nathan Briggs
Keyword(s):  
Organic Carbon ◽  
Circulation Model ◽  
Biological Data ◽  
Ocean Modeling ◽  
Biogeochemical Model ◽  
Identification Algorithm ◽  
Low Oxygen ◽  
The South ◽  
Regional Ocean Modeling System ◽  
Wide Range

<p>The Angola-Benguela frontal region represents an extremely dynamic portion of the ocean located along the south-western African coast, at the northern edge of the South Atlantic gyre. At this boundary, the northern warm and saline waters of the Angola Basin mix with the southern colder and fresher waters carried by the Benguela current through a combination of processes that span a wide range of spatio-temporal scales. This study combines the use of underwater glider data collected between February and June 2018 with a high resolution 3D physical-biogeochemical model to investigate how these lateral exchanges impact the oxygen and organic carbon distributions in the proximity of the front. From the glider data, we identify a set of salinity, oxygen and organic carbon anomalies impacting the first 500 m of the water column during February-June 2018. Using satellite images of physical and biological data and an eddy identification algorithm, we discuss these anomalies in the context of the surrounding physical and biological setting at the time of measurement and identify key processes that may be responsible for the observed tracer patterns. We employ the Regional Ocean Modeling System (ROMS) coupled with the Biogeochemistry Ecosystem Circulation model (BEC) to further explain and upscale our findings. We study the dynamics of cross-frontal exchanges of oxygen and organic carbon in the first 500 m depth. We show how the coupling between long filaments and intense anticyclonic eddies forming at the front generates a complex pattern of recirculation of Angola Basin-derived saline and low-oxygen waters into the oxygenated Benguela region. Finally, we quantify the oxygen lateral transport coupled with these dynamics, and discuss the implications for the biological activity in the region.</p>

WATER QUALITY MONITORING IN THE SOUTH SHORE ESTUARIES OF LONG ISLAND, NEW YORK

2018 ◽  
Author(s):  
Rebeka Smith ◽  
◽  
Thomas Badamo ◽  
David J. Barclay ◽  
Devorah Crupar ◽  
...  
Keyword(s):  
Water Quality ◽  
New York ◽  
Long Island ◽  
Water Quality Monitoring ◽  
Quality Monitoring ◽  
The South ◽  
South Shore

scholarly journals ENSO impact on simulated South American hydro-climatology

2006 ◽  
Vol 6 ◽  
pp. 227-236 ◽  
Author(s):  
J. Stuck ◽  
A. Güntner ◽  
B. Merz
Keyword(s):  
Climate Model ◽  
Initial Conditions ◽  
Circulation Model ◽  
Empirical Orthogonal Functions ◽  
South American ◽  
The South ◽  
Time Space ◽  
The Pacific ◽  
Hydro Climatology ◽  
The Impact

Abstract. The variability of the simulated hydro-climatology of the WaterGAP Global Hydrology Model (WGHM) is analysed. Main object of this study is the ENSO-driven variability of the water storage of South America. The horizontal model resolution amounts to 0.5 degree and it is forced with monthly climate variables for 1961-1995 of the Tyndall Centre Climate Research Unit dataset (CRU TS 2.0) as a representation of the observed climate state. Secondly, the model is also forced by the model output of a global circulation model, the ECHAM4-T42 GCM. This model itself is driven by observed monthly means of the global Sea Surface Temperatures (SST) and the sea ice coverage for the period of 1903 to 1994 (GISST). Thus, the climate model and the hydrological model represent a realistic simulated realisation of the hydro-climatologic state of the last century. Since four simulations of the ECHAM4 model with the same forcing, but with different initial conditions are carried out, an analysis of variance (ANOVA) gives an impression of the impact of the varying SST on the hydro-climatology, because the variance can be separated into a SST-explained and a model internal variability (noise). Also regional multivariate analyses, like Empirical Orthogonal Functions (EOF) and Canonical Correlation Analysis (CCA) provide information of the complex time-space variability. In particular the Amazon region and the South of Brazil are significantly influenced by the ENSO-variability, but also the Pacific coastal areas of Ecuador and Peru are affected. Additionally, different ENSO-indices, based on SST anomalies (e.g. NINO3.4, NINO1+2), and its influence on the South American hydro-climatology are analysed. Especially, the Pacific coast regions of Ecuador, Peru and Chile show a very different behaviour dependant on those indices.

scholarly journals Controls on the water vapor isotopic composition near the surface of tropical oceans and role of boundary layer mixing processes

2019 ◽  
Author(s):  
Camille Risi ◽  
Joseph Galewsky ◽  
Gilles Reverdin ◽  
Florent Brient
Keyword(s):  
Water Vapor ◽  
Isotopic Composition ◽  
General Circulation ◽  
Model Simulation ◽  
Circulation Model ◽  
Sea Surface ◽  
Trade Wind ◽  
Mixing Processes ◽  
Tropical Oceans ◽  
Air Mixing

Abstract. Understanding what controls the water vapor isotopic composition of the sub-cloud layer (SCL) over tropical oceans (δD0) is a first step towards understanding the water vapor isotopic composition everywhere in the troposphere. We propose an analytical model to predict δD0 as a function of sea surface conditions, humidity and temperature profiles, and the altitude from which the free tropospheric air originates (zorig). To do so, we extend previous studies by (1) prescribing the shape of δD0 vertical profiles, and (2) linking δD0 to zorig. The model relies on the hypotheses that δD0 profiles are steeper than mixing lines and no clouds are precipitating. We show that δD0 does not depend on the intensity of entrainment, dampening hope that δD0 measurements could help constrain this long-searched quantity. Based on an isotope-enabled general circulation model simulation, we show that δD0 variations are mainly controlled by mid-tropospheric depletion and rain evaporation in ascending regions, and by sea surface temperature and zorig in subsiding regions. When the air mixing into the SCL is lower in altitude, it is moister, and thus it depletes more efficiently the SCL. In turn, could δD0 measurements help estimate zorig and thus discriminate between different mixing processes? Estimates that are accurate enough to be useful would be difficult to achieve in practice, requiring measuring daily δD profiles, and measuring δD0 with an accuracy of 0.1 ‰ and 0.4 ‰ in trade-wind cumulus and strato-cumulus clouds respectively.

The Second Crusade as Seen by Contemporaries

Traditio ◽  
1953 ◽  
Vol 9 ◽  
pp. 213-279 ◽  
Author(s):  
Giles Constable
Keyword(s):  
North Coast ◽  
Holy Land ◽  
The South ◽  
The West ◽  
The Balkans ◽  
The North ◽  
River Elbe ◽  
Medieval Europe ◽  
South Shore ◽  
Naval Force

The years between 1146 and 1148 were signalized in the annals and chronicles of Medieval Europe by Christian campaigns on all fronts against the surrounding pagans and Moslems. The most important of these was directed towards the Holy Land, against the Moslems, who had recently seized Edessa. It consisted of no less than five expeditions. The two largest armies, commanded by the Emperor Conrad III and King Louis VII of France, followed the same route overland across the Balkans to Constantinople; both met with crushing defeats in Asia Minor and finally reached the Holy Land, as best they could, by land and sea. A third force, under Amadeus III of Savoy, moved down Italy, crossed from Brindisi to Durazzo, and joined the army of Louis at Constantinople late in 1147. In August of the same year a naval expedition led by Alfonso of Toulouse left the South of France and arrived in Palestine probably in the spring of 1148. At the same time, a joint Anglo-Flemish naval force sailed along the north coast of Europe, assisted the King of Portugal in the capture of Lisbon, proceeded around the peninsula early in 1148, attacked Faro, and presumably reached the Holy Land later that year. Meanwhile, in the northeast, four armies co-operated in a campaign against the pagan Wends across the river Elbe: a Danish army joined the Saxons under Henry the Lion and Archbishop Adalbero of Bremen in an attack on Dubin; another, larger, army led by Albert the Bear of Brandenburg and many other temporal and spiritual lords advanced against Demmin and Stettin; a fourth expedition, finally, under a brother of the Duke of Poland attacked from the southeast. In 1148, on the south shore of the Mediterranean, a powerful fleet under George of Antioch extended the control of Roger II of Sicily over the entire littoral from Tripoli to Tunis. In the West, four campaigns were directed against the crumbling power of the Almoravides. The Genoese in 1146 sacked Minorca and besieged Almeria. During the following year, the Emperor Alfonso VII of Castile advanced south through Andalusia and captured Almeria with the aid of a strong Genoese fleet, which in 1148 sailed north and joined the Count of Barcelona in his campaign against Tortosa. In the previous year, Alfonso Henriques of Portugal had captured Santarem and secured the assistance of the Anglo-Flemish fleet for an attack on Lisbon, which fell late in 1147.

Sign in / Sign up

Export Citation Format

Share Document