Breeze Effect Research Articles

Effects of sea-land breeze on air pollutant dispersion in street networks with different distances from coast using WRF-CFD coupling method

A WRF-CFD coupled model with high-temporal resolution is employed to investigate pollutant dispersions during a sea-land breeze (SLB) day in an identical building block configuration at three locations in Shanghai, China, and the blocks are set at the coast (L1), downtown (L2) and inland (L3). The results show that the localized wind speed drops below 1 m/s during the sea-land-breeze collision period (SLBCP), which leads to pollutant accumulation. The closer the block is to the coast, the earlier occurrence and longer duration of SLBCP, and Blocks L1, L2, and L3 experience SLBCPs during the morning peak traffic period (MPTP), low-traffic-volume period (at midday), and evening peak traffic period (EPTP), with durations of 2.5 h, 2 h, and 1 h, respectively. Due to the low wind speeds of both land breezes and sea breezes during the overlap of MPTP and SLBCP, the pollutant concentration in Block L1 is significantly elevated, and the peak concentration is two times higher than that in the non-coastal blocks (L2 and L3). Block L2 shows a peak concentration during the midday low-traffic-volume period, while no evident peak concentration is found in L3 in EPTP. The mean concentrations in Blocks L1, L2, and L3 during EPTP are 72 %, 57 %, and 31 % lower than those during MPTP, respectively. This suggests that SLB has significantly different effects on wind fields and pollutant dispersion in building blocks with different distances from the coast and can provide reference data for transport planning in coastal cities.

Diurnal and seasonal dynamics of the canopy‐layer urban heat island of Kuwait

AbstractThis study examines the temporal and spatial variability of near‐surface air temperature and the canopy layer urban heat island (UHICL) of Kuwait City. Observations collected at 12 locations across the country of Kuwait and for the period 2010–2022 are analysed on an hourly and 3‐hourly basis to provide monthly and diurnal insights of the city's UHICL characteristics. Research on Kuwait's UHICL was first conducted by Nasrallah et al. (International Journal of Climatology, 10, 401–405). Results presented here have been afforded the benefit of additional stations and more extensive data compared with the earlier study. Mean positive UHICL intensities, ranging from 1.1°C to 3.8°C at night, are observed consistently across all months, owing to the prevalence of clear skies from winter to summer. Negative UHICL intensities, indicating a typical daytime urban cool island (UCICL), are most prominent on summer days, exhibiting a mean hourly magnitude range between 0.6°C and 2.6°C that extends into the early parts of the evening. Heat and cool island effects are maintained up to wind speeds approaching 10 m s−1 at the urban periphery. A coastal site near the city demonstrates strong influences of the Arabian Gulf temperatures and associated sea and land breeze effects on UHICL development. The results can be used for comparison with other desert locales, in the evaluation of urban climate models, for urban planning policies and improving local weather forecasts. This study honours in memoriam Dr. Hassan Nasrallah, who produced the first UHICL study in the Arab World.

Effects of Sea Land Breeze on Air‐Sea Turbulent Heat Fluxes in Different Seasons Using Platform Observation in East China Sea

AbstractUsing 2‐year platform observations, this study investigates seasonal characteristics of sea land breeze (SLB) and how it influences air‐sea turbulent heat fluxes (THFs) in the coastal areas of East China Sea (ECS) in different seasons. Unlike other SLB studies, this study uses hourly observation on a sea platform to explore SLB's effect on both air‐sea latent heat and sensible heat transferring. The results show that sea wind (SW) does not have an obvious seasonal variation pattern while land wind (LW) is stronger in autumn and winter. The SLB day number shows a clear seasonal variation pattern, which accounts for 38.04% and 18.23% of summertime and wintertime days, reaching its peak and bottom respectively. The latent heat flux (LHF) and sensible heat flux (SHF) are high in autumn and winter while low in summer. The SLB‐contributed LHF and SHF reach peaks in autumn and winter, which are 61.07 and 7.39 W/m2 respectively. The contribution importance of SLB on air‐sea sensible/latent heat transferring is highest in summer while lowest in winter. On SLB days, the SHF decreases significantly by at least about 50% while LHF decreases moderately in all seasons, among which spring witnesses an inversion of sensible heat transferring direction. The warming effect of SLB is mainly responsible for the slump of SHF on SLB days. Multiple factors including relative humidity (RH), background wind field and in situ radiation cause the LHF decrease together, whose changing range varies with season.

Effects of the river breeze on the transport of gases in Central Amazonia

River breezes occur regularly along the Amazonia river but little is known about their effects on air pollution. During the first week of August 2014, river breeze events were observed on two days on the banks of the Negro River, central Amazonia. The WRF-Chem model was used to analyze this period to understand the formation mechanism and the influence of the river breeze on the transport of pollutants such as ozone (O3) and carbon monoxide (CO). We show that the river breeze occurred due to a reduction of the easterly winds associated with the cooling of the waters of the Negro River. The river breeze was responsible for inhibiting the transport of pollutants to the East, increasing its concentrations while breeze circulation is observed, as well as a re-circulation of these gases on the riverbank where the breeze was associated. The strongest breeze occurred in a forest region which maintained the highest concentrations of CO and O3 on the East bank of the Negro River. In the Urban region, the breeze was less intense and had a shorter duration, however, it was still able to maintain higher concentrations of CO and O3 in the western region of the city of Manaus, which is a predominantly residential region and therefore, the population of this region lives in a more polluted environment during the occurrence of breezes.

Does size matter? Modelling the cooling effect of green infrastructures in a megacity during a heat wave

The vulnerability of urban ecosystems to global climate change becomes a key issue in research and political agendas. Urban green infrastructures (UGIs) are widely considered as a nature-based solution to mitigate climate change and adapt to local urban climate anomalies in cities. However, UGI-induced cooling effect depends on the size, location and geometry of green spaces, and such dependencies remain overlooked. This research aimed to investigate the cooling effect of UGIs of different size under extreme conditions of 2021 summer heat wave for the case of Moscow megacity (Russia) using a numerical mesoclimatic model COSMO. UGIs objects were assigned to one of the four size categories (S, M, L and XL) based on their area. Their cooling effects at the local, non-local and city scales were evaluated based on comparison between the model outcomes for the realistic land cover and simulations for which UGI of a particular size category were replaced by the built-up areas typical for their surroundings. The highest cooling effect was observed for XL size UGIs, which reduced the local heat-wave-averaged air temperatures by up to 3.4 °C, whereas for the S size UGIs it did not exceed 2 °C. The cooling effectiveness for XL category was higher than for S category by 23 % inside the green spaces (locally), by 40–90 % in the buffer zones around the green space (non-locally) and by 35 % for the whole city. More effective cooling of large UGIs is partially explained by their stronger park breeze effect, i.e., impact on the airflow increasing the divergence over green spaces. However, when standardized to the population affected by cooling, the M size UGIs made the strongest contribution to the thermal environment where people live and work. The stronger non-local cooling induced by the largest UGI objects cannot compensate for their remoteness from the built environment.

Decoupling in the vertical shape of HCHO during a sea breeze event: The effect on trace gas satellite retrievals and column-to-surface translation

The effect of sea breeze circulation on stratification of the vertical formaldehyde (HCHO) concentration vertical profiles is explored using a regional atmospheric chemical transport model (CTM) for three synoptically stagnant days focused on the east coast of the U.S in June 2018. During this event, a significant thermal contrast between the Atlantic Ocean and the terrestrial regions (12–17 °C), observed by moderate resolution imaging spectroradiometer (MODIS) and well-captured by the WRF-CMAQ model (15–18 °C), is conducive to monsoon-like flow, perpendicular to the shorelines, carrying clean marine air masses over the land within a few hundreds of meters above the surface. In contrast, the westerly continental polluted air masses prevail in higher altitudes. These two conflicting flows result in atypical vertical shapes of HCHO concentrations increasing with altitude. This decoupling pattern is so pronounced that we observe total column HCHO negatively correlate with surface concentrations. Comparisons of an accredited global model, GEOS-CF, to surface wind measurements and MODIS skin temperature indicate its poor representation of the sea breeze timing and strength, resulting in GEOS-CF HCHO vertical shapes being drastically different from the WRF-CMAQ. Based on radiative transfer calculations, the differences in the vertical distribution of HCHO between the WRF-CMAQ and that of GEOS-CF in the first 3 km are sufficient to induce a 20–30% error in air mass factors (thus total vertical HCHO column abundances). Through an experiment involving converting HCHO total columns to surface mixing ratios, we demonstrate that GEOS-CF allocates noticeably more HCHO molecules (40–150%) to the surface layer due to the misrepresentation of the vertical shape of HCHO during the sea breeze event. It is known that a significant fraction of the human population lives in coastal areas prone to detrimental effects caused by air pollution, and elevated pollutant concentrations usually occur in synoptically stagnant atmospheric conditions when local circulation patterns come into play; accordingly, our experiments emphasize the importance of the effect a priori profiles can have on satellite-derived applications under such conditions. To ensure that the quantitative representation of satellite-based trace gas retrievals on a daily basis is trustworthy and useable for air quality applications, atmospheric models providing a priori profiles for satellite retrievals should be well-tuned to reproduce complex local circulation such as sea-land breezes.

Study on the Combustion Performance and Industrial Tests of Coke Breeze in Shougang Jingtang Blast Furnace

In this study, the feasibility indicators of the injection of coke breeze for blast furnaces (BFs) were tested. Experiments were conducted on the combustion behavior of coke breeze at different particle sizes, and the effects of ratio of coke breeze in pulverized coal on the combustion performance of blends were studied. On the basis of the above experiments, industrial tests involving injecting coke breeze after milling were carried out in 3# BF of Shougang Jingtang. The results show that most of the coke breeze particle sizes were distributed above 1 mm. The grindability and combustion performance are poor, so the material needs to be ground before mixing with pulverized coal. The best combustibility can be obtained by using a particle size of less than 8.74 μm of coke breeze in the injection. With the increase in the coke breeze ratio, the combustion performance of blended coal worsened; the negative effects of coke breeze can be improved by increasing the proportion of bituminous coal. According to the results of industrial tests, 8% coke breeze in blends had no negative effect on the smelting state, and the output of the BF increased slightly. Industrial tests proved that coke breeze can partly replace anthracite for BF injecting, which reduced the cost of hot metal while realizing the high value-added resource utilization of coke breeze.

Bat bio-assisted sampling (BAS) for monitoring urban heat island

In this study, we demonstrate how urban-dwelling bats can be used to reconstruct Urban Heat Islands (UHI). We term this approach biologically-assisted sampling (BAS). We used Egyptian fruit bats to map the spatial air temperature (Tair) profile. To demonstrate the feasibility of using biologically-assisted sampled data set, we run mixed effects and Geographically Weighted Regression (GWR) models to estimate the impact of urban environment on Tair distribution. Our results suggest that vegetation is a very important mitigating factor in Tair. In the winter, we found an average Tair difference of 2–5 °C between densely urban and nearby vegetative/open areas. A distinct UHI spot was identified in the winter, centered on the Ayalon highway. These differences were lower during the summer night, probably due to a pronounced cooling sea breeze effect along the coastline. Our preliminary results also indicate that BAS sampling provide a 3D view of the UHI phenomenon: the change in Tair above the dense urban area was smaller than above the vegetative area. Since the differences in Tair between densely urban and open/green areas are the largest during the night hours, bats can serve as efficient agents to monitor UHI effects, despite the method limitations.

Impacts of Urban Development between 2002 and 2022 on the Effects of Sea Breezes in Sendai, Japan—Analyzing Heat Balance Mechanism in Urban Space

Sea breezes are important in a coastal urban climate; however, the impact of urban development on the effects of sea breezes, which decrease air temperature and increase humidity, has not been understood quantitatively. To quantitatively evaluate this impact in Sendai, Japan over the past twenty years, this study analyzed the heat balance mechanisms in urban spaces based on the simulation results of the Weather Research and Forecasting (WRF) model coupled with Local Climate Zone (LCZ) maps. Compared to the observation data on air temperature, specific humidity, and wind in August 2002, results of the numerical simulation, using the 2002 LCZ map and the meteorological conditions of August 2002, confirmed that the WRF model could reproduce meteorological factors well. Thereafter, two numerical simulations using the LCZ maps from 2002 and 2022 were conducted based on the same meteorological condition, from 25 July to 1 September 2008, to extract the impact of urban development on the effects of sea breeze. Consequently, when land use changed from urban built-up land to natural land cover, both the effects of sea breeze—decreasing air temperature and increasing humidity—decreased. Additionally, increases in LCZ 3 (compact low rise), mainly from LCZ 6 (open low rise) and LCZ 9 (sparsely built), decreased the effects of sea breeze (decreasing air temperature and increasing humidity) by 5% and 10%, respectively, in areas around Sendai Station. This was because the consumption of the sea breeze’s potential to decrease air temperature and increase humidity increased and the wind speed of sea breezes decreased in the windward areas of Sendai Station. These results provide new insights into the impact of urban development on the effects of sea breeze and quantitatively reveal changes in the effects of sea breeze.

Contrasting effects of lake breeze and urbanization on heat stress in Chicago metropolitan area

This study used the latest Weather Research and Forecasting (WRF) model coupled with multilayer urban canopy models to investigate contrasting effects from urbanization and lake breeze on summer heat stress over the Chicago metropolitan area (CMA). Comparisons between the model and in situ observations show that this coupled modeling system better captures urban locations' diurnal pattern of surface air temperature, skin temperature and relative humidity, with root mean square error reduced from 1.58 to 1.80 °C to 1.14–1.31 °C, 3.11–3.55 °C to 1.81–2.21 °C, and 10.73–11.35% to 7.84–8.60%, respectively, compared to WRF without coupling the urban canopy models. Two sensitivity experiments were conducted to isolate the influence of lake breeze and urbanization: one replaced the urban land use with cropland over the CMA, and the other filled all of Lake Michigan with cropland. Three different heat stress indices were computed to assess the uncertainties of heat stress response to changes in air temperature, relative humidity, and wind conditions. Results show that, when the lake has the largest cooling effect on air temperature, it also increases the relative humidity the most, and vice versa for urban warming and drying effects. Urbanization intensifies heat stress at night, and extends the heat caution period by up to 4 h over inland urban grids; the lake breeze relieves heat stress during afternoon (when the heat stress is the worst), and shortens the heat caution period by 1–3 h over inland urban grids and 3–4 h over coastal urban grids. The intensification of heat stress over the CMA due to urbanization is more than four times greater than the reduction from the lake breeze in the late afternoon and evening.

Analysis of the wind regime at high spatial-temporal resolution in the itacaiúnas river watershed, eastern amazon

In the present study, hourly wind direction and speed data from six subregions along the Itacaiúnas River watershed (IRW), Eastern Amazon, are analyzed over a 1-year period. The data are acquired from six hydrometeorological stations located in areas of the IRW with different characteristics of land use and plant cover. Among the stations studied, Serra Leste (mine to pasture transition) stands out, with prevailing winds from the Southeast and the East-Southeast, in addition to higher wind speeds. In contrast, at the Salobo (forest) station, the lowest wind speeds are observed, and this station presents the highest percentage of calm winds (60%) in the series. In the analysis of the daytime (from 6 a.m. to 5 p.m.) and nighttime (from 6 p.m. to 5 a.m.) wind cycles, the breeze and mesoscale circulation system are identified. Predominantly northerly winds are observed acting on the Abadia Farm and IFPA Rural (Federal Institute of Education, Science and Technology of Pará) stations, both during the day and at night, overlapping with the local breeze effects. Daily (24 h) and associated breeze circulation (12 h) cycle frequency signals are identified through wavelet transform analyses of the wind for all stations. The interference from large-scale phenomena, such as the Intertropical Convergence Zone (ITCZ) and the South Atlantic Convergence Zone (SACZ), which operate in the region, is evident. Finally, the data show that the differences in wind patterns are also due to environmental aspects such as plant cover, land use, and topography.

Sea-Breeze Front Research Based on Remote Sensing Methods in Coastal Baltic Sea Climate: Case of Lithuania

Sea breezes, as one of the most important local varieties of daily wind dynamics, are responsible for the formation of the climate by coasts of large bodies of water. In recent decades, due to climate change, the air temperature is rising, causing larger temperature gradients to form and the dynamics of the atmosphere to change globally and locally. This research investigated the spread of sea breezes in the years 2018–2019 during the warm period of the year (June, July, and August) to the mainland territory of the southeastern Baltic and coastal Lithuania by applying in situ and remote methods. The results of the study showed that sea-breeze fronts are better identified by the formation line of convective clouds in the continental part seen in remote images. During the first half of the day (until noon), the effect of sea breezes extends on average about 20–30 km from the coast of the sea. However, maximum extension of the breeze fronts can penetrate the continent much further than previously thought. During the summer, when the westward movement of air masses prevails, the band of cumulus (Cu) clouds formed by the sea breeze marks the front of the sea breeze, and at the time of the most extended spread (around 5 pm) in the continental part of Lithuania, the sea-breeze front is an average of around 60 km away from the seacoast. Until noon, the area covered by sea breezes in the western part of Lithuania extends over 1886.2 km2. During the second half of the day, the spatial spread of the breeze impacts an average area of about 6445.2 km2 by around 5 pm. Hence, the sea breeze affects not only the coastal climate region of Lithuania, as previously recognized, but it also affects the climate of part of the region of the Samogitian (Žemaitijos) Uplands of Lithuania. Remote-sensing methods helped to identify sea-breeze fronts and evaluate the limits of marine climate expansion along the seashore. The methods used in this work can play a role in answering the question of how climate change can affect the coastal climate.

Surface atmospheric electric field variability at a desert site

Measurements of atmospheric electrical variables in arid desert environments provide a route to assessing dust charging, which affects dust lofting; satellite remote sensing of dust particles; long range transport of elevated dust layers; and may also influence rain droplet size. This paper analyses a new dataset of atmospheric electric field (or Potential Gradient, PG) measurements from an arid site, at Al Ain in the United Arab Emirates (UAE), to investigate the influence of local meteorological and dust processes on the PG, and assess whether global atmospheric electric signals are detectable. With no data selection applied, the diurnal PG variation has a single maximum around 14UT (18LT), which is likely to be associated with the sea breeze, present on 77% of days in the central UAE. Despite the abundance of apparently fine days meteorologically, conventional atmospheric electricity fair weather selection criteria are not effective at removing all locally generated PG variability. Even applying much stricter selection criteria (10 m wind speed(U10 )between 1 and 5 m/s, visual range >25 km, and no present weather), a diurnal variation in PG with a single maximum at 07UT (11LT) remains, likely due to local convection at sunrise. Although the stricter criteria can remove the sea breeze effect – associated with a visual range change - the PG measurements remain dominated by local meteorological and dust processes. This obscures the usual behaviour of the Global Electric Circuit. Exceptionally large PG values (∼kV/m, even for U10 < 8 m/s when no dust events are detectable visually) indicate that such desert regions can be a highly electrified environment, at least during daytime and during the summer convective months. The regular generation of highly charged dust observed is relevant to evaluating charge effects on large range transport of dust, preferential scavenging of charged dust by water droplets and obtaining accurate satellite retrievals of dust concentration.

Analysis and Mapping of Sea Breeze Event Time in Coastal Cities: A Case Study of Sendai

Due to global warming and urbanization, high-temperature events—which frequently occur in cities—are presenting an increasing threat to the daily lives of human beings. In coastal cities, sea breezes can cool the near surface and improve the urban environment to some extent. Understanding the cooling characteristics of sea breeze on the urban environment is informative for improving and mitigating the urban heat island (UHI) effect. In this paper, we analyze the basic characteristics of the timing of the cooling effect of sea breeze in urban summer based on the long-term multi-point measurements of air temperatures. Additionally, the Weather Research and Forecasting (WRF) model is used to show the influence of sea breeze on cities in terms of the cooling action time. The whole process is reproduced based on a time distribution map created using the results of the WRF simulation. The measured temperature and WRF simulation results are also evaluated with observations. The results show little difference between the two. The analysis of the distribution map shows that the sea breeze gradually penetrates inland from coastal areas. It can therefore be concluded that the sea breeze blows at different speeds in different areas. Our results show that the sea breeze is weak in places near the coast, while it is significantly stronger around inland rivers. Moreover, in urban areas that are far from inland rivers, the speed of the sea breeze is evenly distributed in space. The spatial pattern of sea breeze retreat time and arrival time is reversed: retreats happen earlier in inland areas. The duration of the sea breeze shows a significantly decreasing trend from the coast to inland, with the longest duration at the southern end of the urban area near the coast.

Study of the convergence of low cloudiness by the effect of ocean breeze using the regional climate model

This work sought to analyze in high resolution the downscaling of the global model Climate Forecast System Version 2 (CFSv2) by using the regional climate model RegCM-4.9. The precipitation fields were generated in two different domains and spatial resolution with 10 km and 3 km, for August to October 2020. The equatorial region of Northeast Brazil can be characterized by the complex dynamics that encompass atmospheric movements such as the existence of convergence at low levels of convective cloudiness and its diurnal effect on low cloud cover and its influence on evident precipitation. However, for meteorological scales with a daytime circle, the land-ocean breeze effect in the Gulf of Maranhão in this theoretical model of night convergence shows a peak between 6 to 9 am local time. This work seeks to recognize the existence of land-ocean breeze in Alcântara and its influence on the daytime precipitation cycle, its dynamics can influence aerospace activities by increasing convergence and, depending on its intensity, generating more intense rainfall in the coastal region even in the dry period, which corresponds to the most suitable period for the operational activities of the Alcântara Launch Center.

Assessing Spatial Variation of PBL Height and Aerosol Layer Aloft in São Paulo Megacity Using Simultaneously Two Lidar during Winter 2019

This work presents the use of two elastic lidar systems to assess the horizontal variation of the PBL height (PBLH) and aerosol layer aloft in the São Paulo Megacity. These two lidars performed simultaneous measurements 10.7 km apart in a highly urbanized and relatively flat area of São Paulo for two winter months of 2019. The results showed that the PBLH differences display diurnal variation that depends on the PBL during daytime growth phases. Cloud and sea breeze effects control most of PBLH variation. In the absence of cloud and sea breeze, the maximum difference (~300 m) occurs in the rapid development stage and is due to topographic effects. When the PBL approaches its maximum daily value, it tends to level off with respect to the topography. In addition, it was presented a method that combines elastic lidar (to detect an aerosol layer) and satellite data (to classify such a layer from Aerosol Optical Depth (AOD) and Aerosol Index (AI) information) for the detection of biomass burning events. This methodology demonstrated that the variations caused by Biomass Burning in AOD and AI enable both the detection of aerosol plumes originating from biomass burning and the identification of their origin.

Detecting and characterizing simulated sea breezes over the US northeastern coast with implications for offshore wind energy

Abstract. With the planned construction of vast offshore wind farms along the US East Coast, identifying and understanding key coastal processes, such as sea breezes, has become a critical need for the sustainability and development of US offshore wind energy. In this study, a new two-step identification method is proposed to detect and characterize three types of sea breezes (pure, corkscrew and backdoor) over the US northeastern coast from a year-long WRF (Weather Research and Forecasting) simulation. The results suggest that the proposed detection method can identify the three different types of sea breezes in the model simulation. Key sea breeze features, such as the calm zone associated with pure sea breezes and coastal jets associated with corkscrew sea breezes, are evident in the sea breeze composite imagery. In addition, the simulated sea breeze events indicate a seasonal transition from pure to corkscrew sea breeze between March and August as the land–sea thermal contrast increases. Furthermore, the location and extension of the sea breeze front are different for each type of sea breeze, suggesting that the coastal impact of sea breeze varies with sea breeze type. From the wind energy perspective, the power production associated with a 10 MW offshore wind turbine would be approximately 3 to 4 times larger during a corkscrew sea breeze event than the other two types of sea breezes. This highlights the importance of identifying the correct type of sea breeze in numerical weather/wind energy forecasting.

Effects of Sea Breeze on Urban Areas Using Computation Fluid Dynamic—A Case Study of the Range of Cooling and Humidity Effects in Sendai, Japan

Sea breezes have a significant influence on the urban environment of coastal cities. Therefore, the study of the sea breeze cooling range and its relationship with specific humidity is of great significance for improving the urban environment of coastal cities. This study aims to reproduce the climate of Sendai using the regional Weather Research and Forecasting (WRF) model, clarify the influence range of sea breezes in Sendai, and create an urban environmental climate map. The results revealed a strong correlation between the measured temperatures and the calculated results, and that the cooling effect range of sea breezes was mainly concentrated in the coastal area. In addition, the temperature rise mitigation effect changed over time, and although the maximum mitigation effect range affected a part of the urban area, it did not reach the inland area. In comparison, the specific humidity increased over time from the coastal area to the inland area. It was found that sea breezes mainly affected a part of the urban area and coastal areas in terms of temperature, but affected inland areas in terms of specific humidity. The results show that the range of the cooling effect of sea breezes on temperature was only concentrated within 5 km of the coast; in terms of moderating the temperature rise, there was an effect within the area ~7 km from the coast. In terms of humidity, the effect of sea breezes occurred approximately 1 h later than the effect of temperature.

Impact of a sea breeze event on geochemical behavior of aerosols at a Mediterranean coast (Northern Tunisia)

The aim of this study is to identify the impact of a sea-land breeze circulation on the ventilation of air masses over the Mediterranean Tunisian coast (Boukornine area) during the summer period. Our results show the Mediterranean Sea has an important effect on the chemical characteristics of atmospheric aerosols by the advection of particles from the sea to the coastal site. Indeed, the daytime sea breeze as well the nighttime land breeze limit the ventilation of air masses by the redistribution of aerosols. Besides, it was found that higher concentrations of sodium, chlorine and sulfur over the examined area are associated with the sea-land breeze recirculation while the crustal constituents stay practically constant with some fluctuations due to local effect. The contribution of sea-breeze in Boukornine area was more important than those recorded in other sites in Tunisia. This study proves the high influence of topography which increases the effect of sea-breeze.

Effects of the sea-land breeze on coastal ozone pollution in the Yangtze River Delta, China

Aim at the effects of the coastal characteristic on ozone pollution in the Yangtze River Delta (YRD), a campaign was launched at the Ningbo, China in the summer of 2020, which mainly covered the monitoring of the vertical profiles of ozone (O3) concentration, three-dimensional wind field, temperature and humidity profiles and parameters of boundary layer dynamic-thermodynamic structure. At the coastal research station, a sea-land breeze (SLB) circulation accompanied by a concurrent coastal low-level jets (CLLJ) structure was observed and identified during 11–12 May 2020. The sea breeze first formed at 10:00 LT on 11 May, turned to land breeze at night, and returned to sea breeze again at 10:00 LT the next morning, prevailing at altitudes of 0–0.5 km and 0–0.3 km respectively. Land breeze at night carries O3 from the inland to the sea forming high ozone levels over the sea, and the shift of the sea breeze during daytime further blew pollution back to the land. Additionally, the conversion of SLB contributed to the occurrence of CLLJ at the altitudes of ~0.3–0.7 km by 02:00 and 06:00 LT, of which the center of wind speed reached ~13 m s−1. The CLLJ-induced turbulent activity decoupled the residual layer (RL) and stable boundary layer, leading to a reduction of RL-O3 levels and an increase of ~50 μg m−3 in surface-O3 concentration. The YRD's unique coastal characteristics make O3 pollution causes in coastal areas more complicated.