Showing papers on "Sea breeze published in 2003"

Sea breeze: Structure, forecasting, and impacts

Abstract: [1] The sea breeze system (SBS) occurs at coastal locations throughout the world and consists of many spatially and temporally nested phenomena. Cool marine air propagates inland when a cross-shore mesoscale (2–2000 km) pressure gradient is created by daytime differential heating. The circulation is also characterized by rising currents at the sea breeze front and diffuse sinking currents well out to sea and is usually closed by seaward flow aloft. Coastal impacts include relief from oppressive hot weather, development of thunderstorms, and changes in air quality. This paper provides a review of SBS research extending back 2500 years but focuses primarily on recent discoveries. We address SBS forcing mechanisms, structure and related phenomena, life cycle, forecasting, and impacts on air quality.

Detection of Urban-Induced Rainfall Anomalies in a Major Coastal City

Abstract: There is increasing evidence that large coastal cities, like Houston, Texas, can influence weather through complex urban land use- weather-climate feedbacks. Recent work in the literature establishes the ex- istence of enhanced lightning activity over and downwind of Houston. Since lightning is a signature of convection in the atmosphere, it would seem rea- sonable that urbanized Houston would also impact the distribution of rainfall. This paper presents results using data from the world's first satellite-based precipitation radar (PR) aboard the Tropical Rainfall Measuring Mission (TRMM) and ground-based rain gauges to quantify rainfall anomalies that we hypothesize to be linked to extensive urbanization in the Houston area. It is one of the first rigorous efforts to quantify an urban-induced rainfall anomaly near a major U.S. coastal city and one of the first applications of space-borne radar data to the problem. Quantitative results reveal the presence of annual and warm season rainfall anomalies over and downwind of Houston. Several hypotheses have surfaced to explain how the sea breeze, coastline curvature,

Diurnal patterns of rainfall in northwestern South America. Part III: Diurnal gravity waves and nocturnal convection offshore

Abstract: Afternoon/evening near-coastal convection over land is easily understood as a response to solar heating of the land, turbulent transfer of heat and moisture to the boundary layer, and lifting of air by vigorous sea-breeze fronts. Subtler processes apparently underlie the late night and morning convection that is prevalent over coastal waters throughout the Tropics. Sensitivity tests using the fifth-generation Pennsylvania State University–NCAR Mesoscale Model (MM5), and further diagnoses of the control run described in Part II, are used to explore these processes. Prior studies have speculated that “land-breeze” circulations, analogous but opposite to the sea breeze, drive offshore convection at night. However, nighttime radiative cooling of land and the associated thermal breezes are much weaker than the corresponding daytime processes, especially under humid tropical skies. Analysis of model mean soundings reveals that modest (fractions of a degree Celsius) temperature changes near the 800-hPa ...

Measuring the sea breeze from QuikSCAT Scatterometry

Abstract: [1] Differences between morning and evening winds from QuikSCAT scatterometer measurements are analyzed to diagnose the diurnal variability of the wind over the ocean. A statistically significant signal, associated with the sea breeze, is present along most of the world's coastlines. Significant diurnal variability is also present mid-ocean in the easterly trade wind belts.

Cloud‐to‐ground lightning enhancement over Southern Louisiana

Abstract: [1] Fourteen years (1989–2002) of cloud-to-ground (CG) lightning data show a significant enhancement of lightning associated with Lake Charles and Baton Rouge, Louisiana. A peak density value of 7 flashes km−2 yr−1 exists on the western side of the Lake Charles urban area. A comparison of the Louisiana CG flash density distribution with the locations of PM10 (particulate matter less than 10 μm in diameter) sources strongly suggests that pollution plays a key role in lightning enhancement. Urban and sea breeze effects can be neglected. The values of median peak negative current show a sharp difference between land and the Gulf of Mexico; inland values are near 24 kA, while over the Gulf waters immediately offshore are over 30 kA. This observation, along with a relative minimum of negative peak current from the mouth of the Mississippi River southeastward seems to support the hypothesis that the underlying surface characteristics influence the calculated negative current distribution.

Interaction between an Inland Urban Heat Island and a Sea-Breeze Flow: A Laboratory Study

Abstract: Using laboratory experimental data taken from a temperature-controlled water tank, the basic features of the circulation associated with an inland urban heat island (UHI) of diameter D and surface heating rate H0 and its interaction with a sea-breeze current were investigated. When the environment was stably stratified with a buoyancy frequency N (nocturnal UHIs) and the sea breeze was absent, the UHI circulation was mainly governed by the Froude number [Fr = U/(ND)], in agreement with theoretical predictions found in literature (U was the horizontal velocity scale of the flow based on H0 and D). Furthermore, the results were in agreement with other laboratory studies and with nighttime field observations conducted in large cities. It was found that U, when calculated with H0 + HL (where HL was the surface heat flux associated with the land temperature growth occurring after sunrise), could also be employed as the velocity scale for UHI circulations that develop in statically unstable environment...

Impacts of topography and land degradation on the sea breeze over eastern Spain

Abstract: A three-dimensional non-hydrostatic atmospheric model RAMS, version3b, is used to examine the impact of complex topography on the sea breeze under heterogeneous and degradation land use characteristics. In the study, it is shown that topography plays an important role in the sea-breeze circulation by aligning the sea breeze front to the coastline and locating the convergence zones close to the mountain range. When the sea breeze is coupled with the upslope wind, the sea-breeze circulation is strengthened by the topography. Sensitivity analyses are carried out to determine the influence of vegetation and soil moisture, i.e., land surface modifications, to this thermally driven flow. Land degradation results in an enhanced sea-breeze circulation which is characterized by a stronger onshore flow, a stronger return current, a larger updraft velocity associated with the sea-breeze front and further inland penetration. Other important features are a deeper sea-breeze depth, a larger downdraft velocity behind the sea-breeze front, and a longer offshore extent. The results also show how land changes modify the sea breeze temporal evolution resulting in an earlier onset and later end. The study stresses the convenience of using three-dimensional models with detailed land surface information to model the sea breeze in complex terrain where land use is rapidly modified.

Urban Photochemical Pollution in the Iberian Peninsula: Lisbon and Barcelona Airsheds

Abstract: Numerical simulations with photochemical transport models were independently performed for two domains situated in the Iberian Peninsula covering the Lisbon and Barcelona airsheds. Although the days chosen for simulation of the two cities are not the same, the synoptic situations in both cases, known as typical summertime situations, were similar, which allowed the development of typical mesoscale circulations, such as sea breezes and mountain and valley winds dominated by the Azores anticyclone. Emission inventories for the two areas were developed. The O3 concentrations recorded in both cities have a similar level. Nevertheless, Ox values in Barcelona are higher than in Lisbon, which may, at a first glance, indicate an apparently more oxidant atmosphere in Barcelona. Photochemical modeling for the two cities has shown that the behavior of the circulatory patterns in both urban areas is rather different, which mainly has to do with the different strengths of the sea breeze and the topography, ind...

Multiseason Verification of the MM5. Part I: Comparison with the Eta Model over the Central and Eastern United States and Impact of MM5 Resolution

Abstract: This paper describes the multiseason verification of the fifth-generation Pennsylvania State University–National Center for Atmospheric Research Mesoscale Model (MM5) and the National Centers for Environmental Prediction (NCEP) Eta Model over the eastern two-thirds of the United States and surrounding coastal waters during the cool (1 November–31 March) and warm (1 May–30 September) seasons from the autumn of 1999 through the summer of 2001. Verification statistics are calculated by interpolating model forecasts to the observation sites. The horizontal and vertical distributions of model errors are presented as are the diurnal and intraseasonal trends. During the cool season, both the MM5 and Eta have a low-level cool and moist bias over land, a significant surface warm bias over water, and surface winds that are too strong over land to the east of the Rockies and too weak over water. The low-level cool and moist bias is maximized during the day, and the cool bias is largest during late winter. D...

Annual and Diurnal Wind Patterns in the City of São Paulo

Abstract: The major topographic, mesoscale, and urban influences on the wind patterns of the City of Sao Paulo are characterized using one year of surface wind velocity data observed at 11 surface stations within its urban limits. The data was used to study the diurnal and annual variations of wind velocity and horizontal wind divergence within the city. Results showed that the circulation over the investigated area is dominated by three major factors: sea breeze; mountain-valley circulations; and urban effects, such as roughness, building-barrier, and urban heat island. The sea breeze was found to be the dominant feature of the monthly-averaged diurnal variation of Sao Paulo surface winds during the eight warmest months of the year. The sea breeze front induces a velocity minimum at the time of its passage and a post-frontal afternoon velocity maximum. Mountain-valley thermal effects on the flow can be seen in the temporal divergence/convergence patterns. These thermal effects tend to be more important during colder months, at night, and when the wind velocities are low. Nighttime downslope convergent flows are present over the city during winter and spring and daytime upslope divergent flows are present over the city during summer months.

A Two-Dimensional Numerical Study of the Impact of a City on Atmospheric Circulation and Pollutant Dispersion in a Coastal Environment

Abstract: The urban impact on the sea breeze is studied by means of a mesoscale model with a detailed urban parameterisation. Four simulations are carried out on an idealised two-dimensional flat domain. In the base case, half of the domain is characterised by sea and the other half by rural land. In the urban case, an urban area 10 km wide is added near the shoreline. Simulations are performed for a moist rural soil (weak sea breeze) and for a dry rural soil (strong sea breeze). Results are analysed in order to evaluate the impact of the city on the wind, temperature and turbulent kinetic energy fields. The dispersion of a passive tracer emitted near the coastline is, also, used in the comparison. Results show that the city accelerates the sea-breeze formation inthe morning (combinations of urban circulation and sea breeze), but it slows the sea-breeze front penetration. Moreover, the presence of the city enhances the recirculation processes and strongly modifies the pollutant dispersion. These effects are enhanced for a moist rural soil.

Influence of changes in the prevailing synoptic conditions on the response of aerosol characteristics to land- and sea-breeze circulations at a coastal station

Abstract: The changes in the response of near surfaceaerosol properties to land- and sea-breezecirculations, associated with the changes in the prevailing synoptic meteorological conditions, are examined for a tropical coastal station Aerosol properties are nearly similar in both the breeze regimes (land and sea) during seasons of marine airmass while they are distinct during seasons of continental airmass As the prevailing winds shift from continental to marine and the ambient weather changes from winter conditions to the humid monsoon season, the submicron mode, which dominated the aerosol mass-size distribution, is largely suppressed and the dominance of the super micron mode increases During periods of continental air mass (winter), the aerosol loading is significantly higher in the land-breeze regime, (particularly in the submicron range) but as the winds shift to marine, the loading initially becomes insensitive to the breeze regimes and later becomes higher in the sea-breeze regime, particularly in the super micron range

Dry deposition of airborne trace metals on the Los Angeles Basin and adjacent coastal waters

Abstract: [1] We present an assessment of the deposition rates of airborne trace metals onto the Los Angeles Basin and adjacent coastal waters. For this purpose, the UCLA Surface Meteorology and Ozone Generation (SMOG) air pollution modeling system has been used to simulate the geographical distributions of trace metals and their deposition fluxes. Calculations were performed for average summer and winter conditions, as well as for extreme meteorological events, in particular, for Santa Ana winds. Thus, a series of simulations were carried out that define the range of meteorological conditions contributing to dry deposition in the region. These predictions have been calibrated and validated using measurements collected in the LA area. Significant spatial and temporal variability are found in trace metal concentrations and deposition rates. Large spatial gradients occur near the coast as well as at the mountainous boundaries of the airshed. Considerable diurnal and seasonal variations in trace metal deposition are also noted. For example, the development of a daytime sea breeze, particularly in the warmer months, leads to greater deposition in the northern and eastern basin as well as in the high desert. A nighttime land breeze, especially in the colder months, enhances deposition onto coastal ocean surfaces. Large particles dominate local trace metal deposition in central urban (and adjacent) areas, while fine particles export metals over regional scales through long-range advection. Since the majority of urban metal deposition occurs on particles larger than 10-mm diameter, routine measurements of PM10 or PM2.5 concentrations for air quality characterization may not be reliable indicators of local sources. Some 35–45% of all trace metal emissions are deposited locally within the Los Angeles Basin on an annual basis. Santa Monica Bay and its watersheds receive about 6% of this amount, which can have a significant impact on trace metal concentrations in the surface waters of the bay, primarily through land runoff following storms. INDEX TERMS: 0345 Atmospheric Composition and Structure: Pollution—urban and regional (0305); 0305 Atmospheric Composition and Structure: Aerosols and particles (0345, 4801); 0368 Atmospheric Composition and Structure: Troposphere—constituent transport and chemistry; 0312 Atmospheric Composition and Structure: Air/sea constituent fluxes (3339, 4504)

Evaluation of the High-Resolution Model Forecasts over the Taiwan Area during GIMEX

Abstract: During the 2001 Green Island Mesoscale Experiment (GIMEX), the fifth-generation Pennsylvania State University–NCAR Mesoscale Model (MM5) was run at a horizontal resolution of 5 km twice a day and forced by initial and boundary conditions from the operational models of the Central Weather Bureau of Taiwan. The purpose of the paper is to evaluate the performance of the surface forecasts of the high-resolution numerical model and to verify quantitative precipitation forecasts (QPFs) over Taiwan Island within the 2-month period. The major errors in the forecasts are surface warm and dry biases. The model also tends to predict a stronger surface wind speed and an inland wind component, which suggest that the model overpredicted the sea breeze, a result that is consistent with the surface warm bias. The underprediction of the precipitation and poor skill scores are possibly due to the inadequate description of the humidity in the initial condition, and a spinup problem due to the steep Central Mountain...

Synoptic-Scale Controls on the Sea Breeze of the Central New England Coast

Abstract: Using routinely available hourly surface observations and United States surface analyses for 2001, a method was developed for predicting sea-breeze events. The method is adaptable to any coastal region in the world where surface data are available. Specific prediction guidelines have been developed using Portsmouth, New Hampshire, as the forecast site. Using Portsmouth METARs (translated roughly from the French as aviation routine weather report), 167 days were determined to have conditions favorable for the occurrence of a sea breeze. Each of these 167 days are classified as either sea-breeze, marginal, or non-sea-breeze events. Sea breezes were defined as insolation-driven local onshore winds. Marginal events were weak sea breezes. Non-sea-breeze events were those days on which sufficient insolation was present but failed to produce a sea breeze at Portsmouth. The surface analyses for these 167 days were used to define a set of synoptic classes based on the arrangement of large-scale pressure s...

A model-aided investigation of winter thermally driven circulation on the Italian Tyrrhenian coast: A case study

Abstract: [1] Data collected during a campaign carried out in and around Rome in February 1996 using sodars, tethered balloon, and surface data suggest the development of a winter sea breeze that could not be detected by conventional data and analyses. A model-aided study is performed to verify the development of thermally driven local circulation and to prove the onset of a winter sea breeze regime, propagating inland and interacting with the urban heat island (UHI). The area of interest for the study is the central part of Italy (latitude 41– 43N, longitude 10–16E). The MM5 mesoscale model was used at high resolution: three nested domains with up to 3 km of grid resolution were used in the area where the sea breeze was observed. To highlight the effect of the sea breeze, a simulation with a thick cloud layer in the innermost domain was performed. By removing the cloud layer the diurnal evolutionofthehorizontaltemperature gradientledtothedevelopmentoftheseabreezeand the UHI circulation, in agreement with the data. Sensitivity tests were carried out to evaluate the effect of land use resolution and of satellite-retrieved/climatological sea surface temperatureonthesimulationresults.Doppler-sodardatarecordedatthreesites,tethersonde profiles, and surface data were used to verify the results. As expected, using high-resolution land use and the daily sea surface temperature retrieved by satellite observations led to improvementsinthelocalcirculationproducedbythemodel.However,themodelfallsshort in reproducing some of the sea breeze characteristics. It finds that the sea breeze starts too early and lasts for a shorter time than the observed one does, and the wind direction shows a too strong northerly component. Also, it slightly underestimates the daily temperature pattern. The interaction of the urban heat islands of Rome and Ostia with the sea breeze flow is analyzed to explain the causes of these discrepancies. INDEX TERMS: 3307 Meteorology and Atmospheric Dynamics: Boundary layer processes; 3322 Meteorology and Atmospheric Dynamics: Land/ atmosphere interactions; 3329 Meteorology and Atmospheric Dynamics: Mesoscale meteorology; KEYWORDS: sea breeze, modeling, urban heat island Citation: Ferretti, R., G. Mastrantonio, S. Argentini, R. Santoleri, and A. Viola, A model-aided investigation of winter thermally driven circulation on the Italian Tyrrhenian coast: A case study, J. Geophys. Res., 108(D24), 4777, doi:10.1029/2003JD003424, 2003.

Conditional Wavelet Technique Applied to Aircraft Data Measured in the Thermal Internal Boundary Layer During Sea-Breeze Events

Abstract: We describe a wavelet-based technique to determine the spectral turbulentcontribution to the vertical flux of sensible heat in a position-wavelength representation. This technique combines awavelet transform (Morlet wavelet) with conditional sampling. We apply this methodto aircraft datacollected during a sea-breeze circulation (BEMA97 experiment) with heterogeneousturbulence conditions horizontally and vertically as well. The turbulent fluxes are analysed with the conditional wavelet techniqueas a function of the wavelength and the horizontal distance.The turbulent processes within the thermal internal boundary layer associatedwith the sea breeze are clearly identified. The results exhibit the wavelength bands through which the upward flux (originating fromthe surface) and the downward flux (originating from the top of theboundary layer) are important.

Sea breeze modulated volatilization of polycyclic aromatic hydrocarbons from the Masnou Harbor (NW Mediterranean Sea).

Abstract: Harbors, marinas, and coastal environments are impacted by important pollutant loadings, particularly of polycyclic aromatic hydrocarbons (PAHs). Air-water exchange is an important process driving the environmental fate of organic pollutants in aquatic environments. However, its relevance as a factor affecting the environmental fate of pollutants from harbor sediments and waters has not been properly assessed, so far, except for few coastal environments. The objective of this study is to quantify the importance of volatilization losses of PAHs from harbor sediments and waters and to study the potential role of sea breeze as a modulator of air-water exchange in coastal environments. The results show that volatilization fluxes from a medium size marina located in the NW Mediterranean sea are relatively high in comparison to those observed in other aquatic systems, particularly for the low molecular weight (MW) compounds. This is consistent with PAHs profiles observed in harbor sediments, which are depleted by the lower MW hydrocarbons. Therefore, volatilization is an important loss of low MW PAHs such as phenanthrene, methyl phenanthrene, dibenzothiophene, etc. Indeed, these PAHs have a residence time of few days in the harbor waters and sediments. Finally, the diurnal trends in volatilization fluxes mimics that of the sea breeze influenced wind speed. These results show the important role that the diurnal sea breeze exerts on the environmental fate of pollutants such as PAHs in coastal environments as a modulator of air-water exchange and as a potential driver of transport of pollutants between adjacent coastal and terrestrial environments.

Estimating Wind Energy Potential Offshore in Mediterranean Areas

Abstract: Relatively few studies have been performed on the evaluation of offshore wind resources, and these have been conducted mostly in Northern Europe. In Mediterranean areas the lack of such studies is mainly linked to (1) the difficulty of meteorological monitoring in deeper waters, (2) the complex orography, frequently extending down to the coasts, (3) the sea breeze wind regimes and (4) local winds such as the Bora, Mistral and Sciroc. In the North Adriatic Sea, a shallow basin of the Mediterranean, the first reason is not applicable, but the others are sufficient to make the evaluation of wind speed methods challenging. In this article we estimate the wind climatology at a platform located 15 km offshore of Venice based on 7 years of data and compare it with the wind climatology obtained by five different methods using the long-term data from four coastal meteorological stations, Venezia Tessera, Venezia San Nicolo, Ronchi and Rimini. We discuss the applicability of these methods and find that the WAsP® model of Riso National Laboratory is still the best tool for wind climate estimates. The results of two new methods are promising, but the methods still require some development. Copyright © 2003 John Wiley & Sons, Ltd.

Identification and characterization of sea breeze days in Northern France using Singular Value Decomposition.

Abstract: Days subject to the development of sea breeze circulations are shown for the months of June and July 2000 in the north of France using an algebraic analysis, the singular value decomposition (SVD). The analysis is performed upon the NOAA-AVHRR radiometric data (with the surface temperature data from the 22 available stations located in the study area). The geostatistical results show the characteristics of a sea breeze blowing from the English Channel and the North Sea. Meteorological situations with a sea breeze are not the prevailing mode in summer over the northern coast of France, but the sea breeze effect can be shown more than 40 km inland. In addition, the results of the SVD allow one to discriminate different weather systems associated with the thermo-topographic winds. Copyright © 2003 Royal Meteorological Society

A note on sea-breeze-induced seasonal variability in the K1 tidal constants in Cádiz Bay, Spain

Abstract: The response of Cadiz Bay to sea-breeze wind stress and tidal boundary forcing—individually and in combination—is studied using a 2D depth-averaged, non-linear, high-resolution hydrodynamic model. Linear superposition of the solution for the K 1 and S 1 constituents, like the solution obtained with an allowance for both the input functions together, is shown to give rise to a modulation of the K1 tidal dynamics. It is precisely this modulation which is responsible for the observed seasonal variations in the K 1 tidal constants in Cadiz Bay.

Main characteristics of sea/land breezes along the eastern coast of the Northern Adriatic

Abstract: An average daily wind regime along the Northern Adriatic eastern coast has been examined at 10 meteorological stations for summertime sea/ land breeze circulation. The stations considered are Pula-Airport, Opatija, Rijeka, Senj, Malinska, Omi{alj, Mali Lo{inj, Rab, Zadar and Zadar-Airport. The aim was to examine the frequency, the times of onset and cessation, the average duration of sea/land breezes, and the impact of the Coriolis force on the wind vector rotation at chosen stations. The results are comparable with corresponding studies of mid-latitude locations. For two stations, an anticlockwise rotation has been discovered (Malinska and Senj), while the remaining stations showed a clockwise rotation, which prevails on the northern hemisphere coasts.

A Statistical Sea-Breeze Prediction Algorithm for Charleston, South Carolina

Abstract: A simple and useful technique for prediction of sea breezes, based on readily available wind vector and air temperature predictions from synoptic models in conjunction with observed coastal sea surface temperatures, is presented for evaluation by coastal forecasters. A statistical prediction scheme using the sea-breeze index has been devised and was found to possess significant nowcasting skill, when used with observed synoptic wind vectors and temperatures and with observed coastal sea surface temperatures. The ready availability of data for these variables and the simplicity of the scheme give it the potential of being useful to many coastal forecast offices, once tuned to the area in which it is applied. The technique can be used on simple workstations or even by manual calculation and thus provides a simple method for local tuning of general-area forecasts to coastal areas. For the 1998 sea-breeze season tested, the algorithm, which was built on June data and tested by nowcasting on data from July through October, had a skill score of 31.3% over climatology.

Systematic observation of westward propagating cloud bands over the Arabian Sea during Indian Ocean Experiment (INDOEX) from Meteosat-5 data

Abstract: [1] During the field experiment phase of the Indian Ocean Experiment (INDOEX), linear cloud formations parallel to the West Indian coast and propagating westward have been observed. Meteosat-5 images are used for the description of the life cycle of these events. Single cloud bands, or main cloud bands followed by (up to 10) secondary parallel cloud lines with a wavelike pattern, have been observed daily during four periods in the dry season of 1999 (15 January, 16–19 February, 27 February to 7 March, and 1–3 April 1999). During these four periods, one single cloud band or a packet of cloud bands is generated every day at nighttime. Their length reaches several hundreds of kilometers, their width lies below 40 km, and their duration in some cases exceeds 24 hours. The smaller cloud lines observed behind the leading cloud line are narrower and are separated by a distance of 2–10 km. Cloud tops are about 3–8°C colder than the Arabian Sea, corresponding to an altitude between 500 and 1200 m during the night and below 2500 m during daytime. Cloud bands travel westward over the Arabian Sea at a speed around 13 m/s, greater than the wind speed measured in the surrounding area. The motion of the cloud band presents similarities with the wavelike propagation of atmospheric phenomena such as the Australian morning glories. Common elements to the different cases are the following: weak low-level winds close to the southwestern Indian coast when the cloud bands appear, winds with a northerly component in the vicinity of the northwestern Indian coast, the presence of a sea-land breeze circulation along the West Indian coast, and the presence of high concentrations of pollutants over the northeastern Arabian Sea. However, existing physical links between these elements (if any) still have to be investigated.