Topic
Sea breeze
About: Sea breeze is a research topic. Over the lifetime, 2544 publications have been published within this topic receiving 55651 citations.
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TL;DR: In this article, the authors focused their interest on analyzing the basic features of different flow fields and thermal structures developed in a complex area and their relation to air pollution problems in the province of Barcelona (in the northeast of Spain).
Abstract: A variety of programmes and field experiments were carried out in order to develop and evaluate models of transport and diffusion of pollutants in complex terrain areas. As part of this programme, in this study, we have focused our interest on analyzing the basic features of different flow fields and thermal structures developed in a complex area and their relation to air pollution problems. The area is located in the province of Barcelona (in the northeast of Spain) close to a wide industrial zone, thus a pollutant flux could affect this region. In order to carry out the main purpose of this study we have analysed data from a Doppler Sodar (FAS 64) and a network of near surface meteorological and air quality stations. In addition, different dynamical simulations given by a numerical mesoscale model (MM5) are also analyzed. The results show that the main flow fields and thermal structures generated in this area are: sea breeze, slope drainage winds, channelling winds created by terrain constrictions and cool-air accumulation in low-lying regions. This last structure, developed specially in winter time, gives rise to stagnant cold air masses and strong thermic inversions, with average lapse rate of −4 degrees on 100 m, which contribute to increase air pollution concentration, especially SO2. Hourly and daily averaged SO2 concentration can be higher than 350 and 138 µg m−3 respectively. In addition, as “La Plana” is located not far from the Mediterranean Sea, during summertime the sea breeze arrives into this zone via its southern entrance, thereby reaching the whole area. The arrival of the sea breeze in to “La Plana”, which advects pollutants from the nearby industrial area, is the main cause of some of these pollutants, especially ozone and its precursors, attaining high concentrations during afternoon hours. The contribution of the sea breeze is variable, but could represent between a 25% to a 30% of its total value.
25 citations
Journal Article•
TL;DR: In this article, the performance of the modeling system before and after optmization were examined, and diurnal variation of features of urban boundary layer was analyzed, through the numerical study of clear day during 6th and 7th Aug-2010 over Beijing area.
Abstract: Weather Research and Forecasting(WRF) modeling system coupled with Noah land surface model and single layer urban canopy model was improved and optimized.Performances of the modeling system before and after optmization were examined,and diurnal variation of features of urban boundary layer was analyzed,through the numerical study of clear day during 6th and 7th Aug,2010 over Beijing area.Furthermore,the impacts of urban underlying surface in Beijing and Tianjin on sea breeze were studied through two groups of model sensitivity tests using optimized modeling system.The results show that the optimization can evidently improve the performance of modeling system in the case study in the article.The modeling system can simulate the features of diurnal variation of summer boundary layer in Beijing generally well.Accurate geography data,such as land use and land cover classification information,play a very important role in improving the accuracy of model results.Beijing city and Tianjin city have obvious impacts on the evolution of sea breeze.As the sea breeze penetrating inland,the cities can pose an obstacle to the landward advance of sea breeze current,strengthen the horizontal convergence of wind and vertical updraft.The urban underlying surface in Beijing can also produce faster penetration with stronger intensity of sea breeze before it reaching the city,and increase the lifecycle and inland penetration distance of sea breeze after it passing over the city.
25 citations
TL;DR: In this article, a three-dimensional coupled mesoscale meteorological and photochemical model has been applied to the Athens basin in Greece, where high pressure system was situated over Greece and the synoptic forcing was weak.
Abstract: A three-dimensional coupled mesoscale meteorological and photochemical model has been applied to the Athens basin in Greece. The Athens area experiences episodes of very high air pollution levels a few times every year. A severe episode on 25 May 1990 was chosen for this study. On this day a high pressure system was situated over Greece, and the synoptic forcing was weak. A sea breeze developed in the basin during the day, and the pollutants were transported out of the basin through the gaps between the mountains to the north and northeast. A northward gradient in ozone concentration was present both in the observations and the model results. Unhealthily high concentrations of nitric oxides and hydrocarbons built up during the night, when it was stably stratified and the wind speeds were low. Variations in parameters, such as terrain influence and deposition processes, are performed to illustrate the sensitivity of the model results. Deposition is shown to be important for the results, although t...
25 citations
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TL;DR: In this paper, the authors illustrate the different types of foundations used for various depths of the ocean, how the turbines function, as well as environmental considerations and recovery of the electricity in offshore wind farms.
Abstract: In Europe there have been many successes with offshore wind farms, since 1991 the installation begun, and there has been 53 European offshore wind farms constructed since. With another ten offshore wind farms under construction, Europe will continue using this source to generate electricity.
Onshore wind farms are successful and used all over the world; however there are disadvantages, such as noise and visual effects, which are eliminated with offshore wind farms. The use of offshore compared with onshore has proven more successful as the turbines and rotor blades are generally much larger than onshore structures and there are less obstructions offshore. There are also stronger winds off the coast, making offshore wind farms ideal.
Offshore wind farms require large foundations and have multiple types that keep them stable in the ocean to withstand high winds and storms. Different foundations are used for varying depths, as well as a sway concept to account for the wave activity from the ocean. The cost to construct these foundations, as well as the turbines, can be quite large, giving offshore wind farms a disadvantage. [1]
The following paper will illustrate the different types of foundations used for various depths of the ocean, how the turbines function, as well as environmental considerations and recovery of the electricity.
25 citations
TL;DR: In this article, the authors measured the surface energy exchanges above the dominant surface types (savanna, grassland, forest and shallow tidal strait) during the monsoon transition period (October-December) using the Bowen ratio and the aerodynamic techniques.
Abstract: [1] Inputs of heat and moisture through surface energy exchanges are important in the evolution of diurnally modulated thunderstorms. As part of the Maritime Continent Thunderstorm Experiment (MCTEX) conducted on the Tiwi Islands, northern Australia, we measured the surface energy exchanges above the dominant surface types (savanna, grassland, forest and shallow tidal strait). Measurements were made during the monsoon transition period (October–December) using the Bowen ratio and the aerodynamic techniques. A full radiation balance was measured at the Savanna site, where the surface albedo was determined as 0.19. The surface energy exchanges showed broad similarities between the sites, with comparable high net radiation totals averaging 11.8 MJ.m−2.day−1 over the terrestrial sites. The substrate heat fluxes were large at the Tidal strait (4.21 MJ.m−2.day−1) due to the high rates of energy absorption into water. The partitioning of net radiation into sensible and latent heat fluxes was controlled primarily by surface characteristics such as soil moisture and vegetation cover, with Bowen ratios averaging 1.08, 0.65, 0.5 and 0.40 for grassland, forest, savanna and tidal strait sites, respectively. A higher Bowen ratio was recorded at the Grassland site as this was during an earlier period that was much drier. Strong relationships were observed between the total surface convective fluxes and boundary layer development (e.g., the lifting condensation level) and between the magnitude of the daytime surface sensible heat flux and the onset time of thunderstorm convection. Observed terrestrial surface fluxes of moisture (averaging 165–265 W.m−2) were deemed insufficient for observed thunderstorm initiation and suggest that sea breeze advection of moisture is necessary. Tiwi Island thunderstorms were shown to represent a dynamic system where surface fluxes are important in generating a boundary layer sufficient to initiate the thunderstorms but where feedbacks between thunderstorms and surface fluxes eventually help terminate the storms.
25 citations