scholarly journals The effect of coastal upwelling on the sea-breeze circulation at Cabo Frio, Brazil: a numerical experiment

1998 ◽  
Vol 16 (7) ◽  
pp. 866-871 ◽  
Author(s):  
S. H. Franchito ◽  
V. B. Rao ◽  
J. L. Stech ◽  
J. A. Lorenzzetti
Keyword(s):  
Coastal Upwelling ◽  
Surface Wind ◽  
Three Dimensional ◽  
Sea Breeze ◽  
Atmospheric Model ◽  
Ocean Model ◽  
Breeze Circulation ◽  
Mesoscale Meteorology ◽  
Forcing Function ◽  
Cabo Frio

Abstract. The effect of coastal upwelling on sea-breeze circulation in Cabo Frio (Brazil) and the feedback of sea-breeze on the upwelling signal in this region are investigated. In order to study the effect of coastal upwelling on sea-breeze a non-linear, three-dimensional, primitive equation atmospheric model is employed. The model considers only dry air and employs boundary layer formulation. The surface temperature is determined by a forcing function applied to the Earth's surface. In order to investigate the seasonal variations of the circulation, numerical experiments considering three-month means are conducted: January-February-March (JFM), April-May-June (AMJ), July-August-September (JAS) and October-November-December (OND). The model results show that the sea-breeze is most intense near the coast at all the seasons. The sea-breeze is stronger in OND and JFM, when the upwelling occurs, and weaker in AMJ and JAS, when there is no upwelling. Numerical simulations also show that when the upwelling occurs the sea-breeze develops and attains maximum intensity earlier than when it does not occur. Observations show a similar behavior. In order to verify the effect of the sea-breeze surface wind on the upwelling, a two-layer finite element ocean model is also implemented. The results of simulations using this model, forced by the wind generated in the sea-breeze model, show that the sea-breeze effectively enhances the upwelling signal.Key words. Meteorology and atmospheric dynamics (mesoscale meteorology; ocean-atmosphere interactions) · Oceanography (numerical modeling)

scholarly journals The co-influence of the sea breeze and the coastal upwelling at Cabo Frio: a numerical investigation using coupled models

2011 ◽  
Vol 59 (2) ◽  
pp. 131-144 ◽  
Author(s):  
Flávia Noronha Dutra Ribeiro ◽  
Jacyra Soares ◽  
Amauri Pereira de Oliveira
Keyword(s):  
Positive Feedback ◽  
Coastal Upwelling ◽  
Coupled Model ◽  
Sea Breeze ◽  
Atmospheric Model ◽  
Breeze Circulation ◽  
Coupled Models ◽  
Initial Field ◽  
Oceanic Model ◽  
Cabo Frio

A coupled atmospheric-oceanic model was used to investigate whether there is a positive feedback between the coastal upwelling and the sea breeze at Cabo Frio - RJ (Brazil). Two experiments were performed to ascertain the influence of the sea breeze on the coastal upwelling: the first one used the coupled model forced with synoptic NE winds of 8 m s-1 and the sign of the sea breeze circulation was set by the atmospheric model; the second experiment used only the oceanic model with constant 8 m s-1 NE winds. Then, to study the influence of the coastal upwelling on the sea breeze, two more experiments were performed: one using a coastal upwelling representative SST initial field and the other one using a constant and homogeneous SST field of 26°C. Finally, two more experiments were conducted to verify the influence of the topography and the spatial distribution of the sea surface temperature on the previous results. The results showed that the sea breeze can intensify the coastal upwelling, but the coastal upwelling does not intensify the sea breeze circulation, suggesting that there is no positive feedback between these two phenomena at Cabo Frio.

scholarly journals Interaction between Coastal Upwelling and Local Winds at Cabo Frio, Brazil: An Observational Study

2008 ◽  
Vol 47 (6) ◽  
pp. 1590-1598 ◽  
Author(s):  
Sergio H. Franchito ◽  
Tania O. Oda ◽  
V. Brahmananda Rao ◽  
Mary T. Kayano
Keyword(s):  
El Niño ◽  
Coastal Upwelling ◽  
Cold Water ◽  
El Nino ◽  
Surface Wind ◽  
Sea Breeze ◽  
Time Frequency ◽  
El Niño Event ◽  
Local Winds ◽  
Cabo Frio

Abstract The relationships between coastal upwelling and local winds at Cabo Frio (Brazil) are studied using SST and time series of surface wind for a 10-yr period (1971–80). The results show that the seasonal variations of SST and local winds are closely related. Sea-breeze circulation is intensified by the enhancement of the land–sea temperature gradient due to cold water upwelling near the coast; coastal upwelling, in turn, is associated with strong northeasterlies. This result confirms the conclusions of earlier modeling studies. Interannual variability is also apparent in the results. During the period from 1971 to 1980, the highest SST values occur during the years 1972–73 (strong El Niño event) and the lowest occur in 1977 (moderate El Niño event). This suggests some possible effects of atmospheric teleconnections on South Atlantic SSTs. However, a record longer than 10 yr is needed to confirm the connection with El Niño and La Niña events. Time–frequency analyses of the SST and zonal wind series for 1975–77 are done using Morlet wavelet analysis. The global wavelet spectra for these variables show strong peaks at 24 and 157 h (approximately 6.6 days). These analyses also indicate that the sea breeze occurs at Cabo Frio almost year-round and confirm the relationships with the coastal upwelling in the region.

scholarly journals An observational study of the evolution of the atmospheric boundary-layer over Cabo Frio, Brazil

2007 ◽  
Vol 25 (8) ◽  
pp. 1735-1744 ◽  
Author(s):  
S. H. Franchito ◽  
V. Brahmananda Rao ◽  
T. O. Oda ◽  
J. C. Conforte
Keyword(s):  
Boundary Layer ◽  
Atmospheric Boundary Layer ◽  
Mixed Layer ◽  
Coastal Upwelling ◽  
Vertical Mixing ◽  
Austral Summer ◽  
Sea Breeze ◽  
Austral Winter ◽  
Atmospheric Mixed Layer ◽  
Cabo Frio

Abstract. The effect of coastal upwelling on the evolution of the atmospheric boundary layer (ABL) in Cabo Frio (Brazil) is investigated. For this purpose, radiosounding data collected in two experiments made during the austral summer (upwelling case) and austral winter (no upwelling case) are analysed. The results show that during the austral summer, cold waters that crop up near the Cabo Frio coast favour the formation of an atmospheric stable layer, which persists during the upwelling episode. Due to the low SSTs, the descending branch of the sea-breeze circulation is located close to the coast, inhibiting the development of a mixed layer mainly during the day. At night, with the reduction of the land-sea thermal contrast the descending motion is weaker, allowing a vertical mixing. The stable ABL favours the formation of a low level jet, which may also contribute to the development of a nocturnal atmospheric mixed layer. During the austral winter, due to the higher SSTs observed near the coast, the ABL is less stable compared with that in the austral summer. Due to warming, a mixed layer is observed during the day. The observed vertical profiles of the zonal winds show that the easterlies at low levels are stronger in the austral summer, indicating that the upwelling modulates the sea-breeze signal, thus confirming model simulations.

scholarly journals See breeze like cloud-free zones during Monsoon months

MAUSAM ◽  
2021 ◽  
Vol 43 (2) ◽  
pp. 163-168
Author(s):  
J. C. MANDAL ◽  
S. R. HALDER
Keyword(s):  
Surface Wind ◽  
Sea Breeze ◽  
Early Morning ◽  
Southwest Monsoon ◽  
Sea Surface ◽  
Clear Zone ◽  
Breeze Circulation ◽  
Clear Area ◽  
Air Temperatures ◽  
Characteristic Features

Characteristic features of district cloud-free zones and their day to day evolution along Indian coasts as observed in INSAT cloud imageries during southwest monsoon months  have been analysed and discussed along with sea surface and surface air temperatures and monsoon condition situation. It was a weak or break monsoon condition. Appearance of early morning clear zone just off shore along Indian Peninsula coasts is attributed to the gradual lowering of sea surface temperate due to upwelling caused by persistent favorable surface wind and slow-setting of air above colder water. With the advance of the day, wide extension of clear area over water where it ends abruptly and propagation of front-like zone inland manifest as a typical sea breeze. It is postulated that this is the effect of sea breeze circulation and shrinking of air above colder water. It is inferred that time-to-time appearance of such phenomenon may be an Indication of longer weak or break monsoon over the Peninsula.

scholarly journals Variability of three-dimensional sea breeze structure in southern France: observations and evaluation of empirical scaling laws

2006 ◽  
Vol 24 (7) ◽  
pp. 1783-1799 ◽  
Author(s):  
P. Drobinski ◽  
S. Bastin ◽  
A. Dabas ◽  
P. Delville ◽  
O. Reitebuch
Keyword(s):  
Scaling Laws ◽  
Three Dimensional ◽  
Surface Friction ◽  
Sea Breeze ◽  
Return Flow ◽  
Doppler Lidar ◽  
Breeze Circulation ◽  
Southern France ◽  
Surface Station ◽  
The Impact

Abstract. Sea-breeze dynamics in southern France is investigated using an airborne Doppler lidar, a meteorological surface station network and radiosoundings, in the framework of the ESCOMPTE experiment conducted during summer 2001 in order to evaluate the role of thermal circulations on pollutant transport and ventilation. The airborne Doppler lidar WIND contributed to three-dimensional (3-D) mapping of the sea breeze circulation in an unprecedented way. The data allow access to the onshore and offshore sea breeze extents (xsb), and to the sea breeze depth (zsb) and intensity (usb). They also show that the return flow of the sea breeze circulation is very seldom seen in this area due to (i) the presence of a systematic non zero background wind, and (ii) the 3-D structure of the sea breeze caused by the complex coastline shape and topography. A thorough analysis is conducted on the impact of the two main valleys (Rhône and Durance valleys) affecting the sea breeze circulation in the area. Finally, this dataset also allows an evaluation of the existing scaling laws used to derive the sea breeze intensity, depth and horizontal extent. The main results of this study are that (i) latitude, cumulative heating and surface friction are key parameters of the sea breeze dynamics; (ii) in presence of strong synoptic flow, all scaling laws fail in predicting the sea breeze characteristics (the sea breeze depth, however being the most accurately predicted); and (iii) the ratio zsb/usb is approximately constant in the sea breeze flow.

scholarly journals Toward a Fully Lagrangian Atmospheric Modeling System

2008 ◽  
Vol 136 (12) ◽  
pp. 4653-4667 ◽  
Author(s):  
Jahrul M. Alam ◽  
John C. Lin
Keyword(s):  
Atmospheric Transport ◽  
Sea Breeze ◽  
Atmospheric Model ◽  
Atmospheric Modeling ◽  
Lagrangian Model ◽  
Staggered Grid ◽  
Breeze Circulation ◽  
Eulerian Model ◽  
Lagrangian Models ◽  
The Cost

Abstract An improved treatment of advection is essential for atmospheric transport and chemistry models. Eulerian treatments are generally plagued with instabilities, unrealistic negative constituent values, diffusion, and dispersion errors. A higher-order Eulerian model improves one error at significant cost but magnifies another error. The cost of semi-Lagrangian models is too high for many applications. Furthermore, traditional trajectory “Lagrangian” models do not solve both the dynamical and tracer equations simultaneously in the Lagrangian frame. A fully Lagrangian numerical model is, therefore, presented for calculating atmospheric flows. The model employs a Lagrangian mesh of particles to approximate the nonlinear advection processes for all dependent variables simultaneously. Verification results for simulating sea-breeze circulations in a dry atmosphere are presented. Comparison with Defant’s analytical solution for the sea-breeze system enabled quantitative assessment of the model’s convergence and stability. An average of 20 particles in each cell of an 11 × 20 staggered grid system are required to predict the two-dimensional sea-breeze circulation, which accounts for a total of about 4400 particles in the Lagrangian mesh. Comparison with Eulerian and semi-Lagrangian models shows that the proposed fully Lagrangian model is more accurate for the sea-breeze circulation problem. Furthermore, the Lagrangian model is about 20 times as fast as the semi-Lagrangian model and about 2 times as fast as the Eulerian model. These results point toward the value of constructing an atmospheric model based on the fully Lagrangian approach.

scholarly journals Sensitivity studies on the air flow characteristics In Kharagpur using a meso-scale model

MAUSAM ◽  
2022 ◽  
Vol 44 (4) ◽  
pp. 329-336
Author(s):  
D LOHAR ◽  
B CHAKRAVARTY ◽  
B. Pal
Keyword(s):  
West Bengal ◽  
Surface Wind ◽  
Three Dimensional ◽  
Flow Characteristics ◽  
Sea Breeze ◽  
Scale Model ◽  
Monsoon Period ◽  
Sea Breezes ◽  
Differential Heating ◽  
South West

  A three-dimensional hydrostatic model has been employed for the study of sea breeze circulations over south West Bengal with special reference to an inland station Kharagpur (22°.21' N, 87° 19'E). A series of sensitivity experiments have been performed to stress the Importance of differential heating on circulation over south West Bengal during pre-monsoon period. It is found that due to differential heating rate between land and sea surfaces, sea breezes can penetrate to the inland station Kharagpur and beyond even in case of moderate gradient wind. Surface observations at Kharagpur and pilot balloon observation at nearby station Kalaikunda are used to compare the model results. The onset of sea breezes, variation of the air temperature and humidity are In fairly good agreement whereas It over estimates the depth of the circulation and cannot predict the variation  of the late morning hours surface wind.

scholarly journals ICONGETM v1.0 – Flexible two-way coupling via exchange grids between the unstructured-grid atmospheric model ICON and the structured-grid coastal ocean model GETM

2020 ◽  
Author(s):  
Tobias Peter Bauer ◽  
Knut Klingbeil ◽  
Peter Holtermann ◽  
Bernd Heinold ◽  
Hagen Radtke ◽  
...  
Keyword(s):  
Data Exchange ◽  
Coastal Upwelling ◽  
Atmospheric Model ◽  
Ocean Model ◽  
Coupled Models ◽  
Structured Grid ◽  
Process Understanding ◽  
Regional Ocean Model ◽  
Coastal Ocean Model

Abstract. Coupled atmosphere-ocean models are developed for process understanding at the air-sea interface. Over the last 20 years, there have been studies involving simulations in the range of sub-annual simulations to climate scenarios. The development of coupled models highly depends on the kind and quality of the required data exchange between the model interfaces. This work achieved the development of a two-way coupled atmosphere-ocean model ICONGETM with flexible data exchange via exchange grids provided by the widely used ESMF regridding package. The regridding of flux data between the unstructured atmosphere model ICON and the structured regional ocean model GETM is conducted via these exchange grids. The newly developed model ICONGETM has been demonstrated for a coastal upwelling scenario in the Central Baltic Sea.

scholarly journals Impact of Ocean–Atmosphere Current Feedback on Ocean Mesoscale Activity: Regional Variations and Sensitivity to Model Resolution

2020 ◽  
Vol 33 (7) ◽  
pp. 2585-2602 ◽  
Author(s):  
Swen Jullien ◽  
Sébastien Masson ◽  
Véra Oerder ◽  
Guillaume Samson ◽  
François Colas ◽  
...  
Keyword(s):  
General Circulation ◽  
Surface Wind ◽  
General Circulation Models ◽  
Atmospheric Model ◽  
Ocean Model ◽  
Model Resolution ◽  
Coupled Models ◽  
Current Feedback ◽  
Regional Variations ◽  
Ocean Atmosphere

AbstractOcean mesoscale eddies are characterized by rotating-like and meandering currents that imprint the low-level atmosphere. Such a current feedback (CFB) has been shown to induce a sink of energy from the ocean to the atmosphere, and consequently to damp the eddy kinetic energy (EKE), with an apparent regional disparity. In a context of increasing model resolution, the importance of this feedback and its dependence on oceanic and atmospheric model resolution arise. Using a hierarchy of quasi-global coupled models with spatial resolutions varying from 1/4° to 1/12°, the present study shows that the CFB induces a negative wind work at scales ranging from 100 to 1000 km, and a subsequent damping of the mesoscale activity by ~30% on average, independently of the model resolution. Regional variations of this damping range from ~20% in very rich eddying regions to ~40% in poor eddying regions. This regional modulation is associated with a different balance between the sink of energy by eddy wind work and the source of EKE by ocean intrinsic instabilities. The efficiency of the CFB is also shown to be a function of the surface wind magnitude: the larger the wind, the larger the sink of energy. The CFB impact is thus related to both wind and EKE. Its correct representation requires both an ocean model that resolves the mesoscale field adequately and an atmospheric model resolution that matches the ocean effective resolution and allows a realistic representation of wind patterns. These results are crucial for including adequately mesoscale ocean–atmosphere interactions in coupled general circulation models and have strong implications in climate research.

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