Showing papers on "Sea breeze published in 1970"

A Numerical Study of the Effect of a Coastal Irregularity on the Sea Breeze

Abstract: The modification of the sea breeze circulation by irregular coastlines is examined by integrating a three-dimensional nonlinear numerical sea breeze model with a large bay incorporated into the surface boundary conditions. The results show that the presence of a bay produces a landward distortion of the sea breeze convergence zone and that within the zone there develop definite extrema of vertical motion, the positions of which are closely related to the bay. Furthermore, the intensity of convergence and upward motion within the zone are distributed asymmetrically with respect to the bay. This is a result of the Coriolis acceleration and the bay-induced component of the pressure-gradient force acting in concert on one side of the bay and in opposition on the other.

Coastal air-circulation system: observations and empirical model 1,, 2

Abstract: Three consecutive early summer studies on the upper Texas coast have produced data that afford a much clearer view of the land and sea breeze system than was previously held. Networks of surface observations, pibal and radiosonde ascents, and aircraft flights have produced observations that are integrated to give a synthesized model of the coastal air-circulation system as a function of space and time.

A Spatial Model of an Urban Heat Island

Abstract: Mean temperatures obtained from 28 midday motor traverses in the Durban area during the summer of,1968–69 show the center of the heat island to be displaced away from the central business district by the sea breeze. The spatial temperature wave across the center of the heat island is described by a simple harmonic model.

Diurnal Variation of Onshore Wind Speed Near a Coastline

Abstract: Surface wind data taken from 19 km offshore to 14 km inland during several days of onshore wind occurrence were reduced and analysed. The mean kinetic enemy per unit mass and its changes normal to the coastline were computed directly from the wind data. Analysis of these data shows two well defined regimes of diurnal variation in wind speed. The marine air has a nighttime speed maximum and a daytime minimum. As the air moves inland, the speed distribution becomes bimodal with the primary maximum occurring in the daytime and the secondary maximum at night. As expected Intuitively and predicted by theory, the speed changes most abruptly near the change in surface roughness (the coastline). Also as predicted by theory, complete dynamic equilibrium with the new lower boundary is not achieved until the air is ∼5–12 km downwind from the coastline.

The shear steess of sea breeze on a swash zone

Abstract: Measurements of shear stress under the effect of a sea hreeze were made by simultaneous wind and temperature profiles over a shore near Fort Walton Beach, Florida It was found that the sea breeze In the surface boundary layer is in the atmospheric free-convection, regime The measured shear stress coefficient is in conformity with that obtained by other investigators by the sea surface tilt method under the unstable condition For coastal applications, the result is found to be more reliable than those assumed coefficients obtained under neutral stability for this localized coastal wind system.

Land Breezes And Rainfall on the Natal Coast

Abstract: The diurnal rainfall at Durban shows highest rainfall frequencies and totals at 2100 with sharp decreases thereafter. A high proportion of this nocturnal precipitation is of low intensity producing less than 1.0 mm/hr. It is suggested that the light nocturnal showers over the coast are produced by undercutting of moist sea air by the cool land breeze. The showers cease with, the arrival of the mountain-plain wind from the interior and subsequent deepening of the cool air layer.

Transport And Distribution Of Air PollutantsIn Athens (Greece): Aircraft MeasurementsDuring MEDCAPHOT - TRACE

Abstract: A series of flights was conducted within the MEDCAPHOT TRACE project between 06 and 15 September, 1994. The goals were to help understand the distribution, transport, and chemical reaction rates of pollutant gases emitted in the large urban agglomeration of the city of Athens. The flight routes covered the Greater Athens Area (about 60 x 60 km), including the inner basin, with low level (50 150 m above water or ground) flight legs. Additionally, vertical profiles were flown southwest and northeast of the city in order to characterize the physical and chemical structure of the boundary layer upwind and downwind of the city. In some cases, a relatively strong northeasterly synoptic flow guaranteed good ventilation in most parts of the Athens basin and thus made an intense build-up of pollution impossible. In other cases, when a strong sea breeze developed during the day, the near-surface flow direction was into the basin from all sides. Therefore, pollutants could escape the basin only vertically, and high concentrations of primary and secondary pollutants built up in layers which were located NE of the city in altitudes of several 100's of meters. From these layers, pollutants were probably incorporated into long range transport towards S.

Modelling The Dispersion Of CO Over Barcelona Area With The Mesoscale Model PROMETEO

Abstract: The mesoscale prognostic model PROMETEO, extended with an equation that describes the evolution of a non reactive pollutant (i.e. a mass conservation equation), has been applied to simulate the dispersion of carbon monoxide over the Barcelona Area, for a typical summer scenario. Both simulated meteorological and concentration data have been compared with measured data. The concentration fields have been analyzed in detail: the horizontal ones show the inland transport due to the sea breeze; while the vertical ones show the influence of the mixing layer on the concentrations and the importance of taking into account the returning flow generated by the breeze cell.

Plume Dispersion Modelling During ASea-breeze Event

Abstract: The Lagrangian Adaptative Volume Plume Model (AVP) was used to simulate the dynamics of a power plant plume during a typical sea breeze period at the east coast of Spain. Data collected during the MECAPIP project around a power plant were used to reproduce the shapes and general behavior of plumes observed by an instrumented aircraft. Results from these simulations show that the model can predict the temporal plume pathway and plume shapes that are frequently observed during sea-breeze events. Concentration patterns were well simulated during fumigation conditions.

Photochemical Modelling Of The Barcelona AreaUnder Weak Pressure Synoptic SummerConditions

Abstract: The city of Barcelona and its surrounding area, located in the western Mediterranean basin, can reach high levels of Og in summertime under weak pressure synoptic conditions. To study the origin of this photochemical pollution, the episode that took place between the 3 and 5 August 1990 was chosen. The main meteorological mesoscale flows that take place in the region, such as sea and land breeze, convection cells and topographic injections, were reproduced with the meteorological non-hydrostatic mesoscale model MEMO for 5 August 1990. Industrial and commercial activity on 5 August 1990 was very low because it was a Sunday in the summer holiday period. Therefore, the emissions inventory calculated for this day in an area of 80x80 knf around Barcelona showed that the main sources of VOC were traffic (51%) and vegetation (34%), while NOx were mostly emitted by traffic (88%). Photochemical simulation with the MARS model has shown that the combination of mesoscale circulations and local emissions is crucial in the production of Og. For instance, NO* inland transport towards regions where biogenic VOC are emitted causes the formation of Os, while topographic injections cause the formation of elevated O] air layers. The synoptic wind, coming from the northeast in this case, also played an important role in advecting the air masses with local generated Os away from their precursor emission sources. Evaluation of the model simulations is also performed and discussed by means of comparison of meteorological measurements in 9 surface stations and concentration measurements in 5 surface stations. Transactions on Ecology and the Environment vol 29 © 1999 WIT Press, www.witpress.com, ISSN 1743-3541