Characteristics of sea breeze in a complex terrain island seen by CERRA

Effect of the sea breeze on the durability of pumice-based supersulfated pastes under accelerated conditions

Influences of sea breeze circulation and atmospheric stability on PM2.5 levels in an inland city of Taiwan

Aerosols are often hypothesized to invigorate deep convective clouds (DCCs), but observational evidence remains limited and inconclusive. Clarifying this hypothesis is critical for regions vulnerable to thunderstorms and flooding, particularly highly polluted coastal cities. Leveraging a novel causal discovery–inference pipeline and high-resolution observations near Houston, TX, we identify multiple causal pathways among aerosols (mostly organic and sulfate), DCCs, and meteorological factors. However, a direct causal link from aerosols to DCCs is found to be uncommon, occurring in less than 35% of analyzed scenarios, and is characterized by strong conditionality and nonlinearity. When aerosol impacts on DCCs do occur, they can be substantial, enhancing DCC core heights by approximately 1.7 km, with 92% of this effect concentrated in warmer-phase cloud regions. Notably, the presence of sea breezes and the inclusion of all measured aerosol particles each enhance DCCs in over 95% of aerosol-sensitive cases.

Abstract This study examines the genesis of atmospheric bores near sunset and their role in initiating and maintaining late‐afternoon mesoscale convective systems (MCSs) over the Southern North China Plain. A key finding is that 20% of documented bore occur during the sunset period. These bores form in the local environment preconditioned by the convective outflows from late afternoon MCSs, or by sea breezes that peak at this time. These bores aid in initiating and maintaining afternoon convection, subsequently favoring the development of nocturnal MCSs and associated bores. While bore research often concentrates on their impact on nocturnal MCSs, this study highlights that accurately predicting the diurnal cycle of MCSs requires properly representing bores. Thus, it helps address the long‐standing challenge of simulating the diurnal cycle of convective rainfall in weather and climate models.

The intensification of urban heat islands in high-density coastal slope areas poses significant challenges to sustainable development. From the perspective of sustainable urban design, this study investigates adaptive greening strategies to mitigate thermal stress, aiming to elucidate the key microclimate mechanisms under the combined influence of sea breezes and complex terrain to develop sustainable solutions that synergistically improve the thermal environment and energy efficiency. Combining field measurements with ENVI-met numerical simulations, this research systematically evaluates the thermal impacts of various greening strategies, including current conditions, lawns, shrubs, and tree configurations with different canopy coverages and leaf area indexes. During summer afternoon heat episodes, the highest temperatures within the building-dense sites were recorded in unshaded open areas, reaching 31.6 °C with a UTCI of 43.95 °C. While green shading provided some cooling, the contribution of natural ventilation was more significant (shrubs and lawns reduced temperatures by 0.23 °C and 0.15 °C on average, respectively, whereas various tree planting schemes yielded minimal reductions of only 0.012–0.015 °C). Consequently, this study proposes a climate-adaptive sustainable design paradigm: in areas aligned with the prevailing sea breeze, lower tree coverage should be maintained to create ventilation corridors that maximize passive cooling through natural wind resources; conversely, in densely built areas with continuous urban interfaces, higher tree coverage is essential to enhance shading and reduce solar radiant heat loads.

Abstract This research introduces a new approach for studying the clear-air boundary layer using high-spatial-resolution three-dimensional wind and thermodynamic fields which can be constantly produced by combining Doppler scanning wind lidars with two advanced retrieval schemes. Two experiments are conducted to highlight the benefits of this approach. In the first field experiment held in a rural area, it is shown that the structure and temporal variation of the boundary layer, including the land–sea breeze, the occurrence of a nocturnal low-level wind maximum, the diurnal cycle in the temperature field, and a semidiurnal cycle in the pressure field, can be accurately captured. In the second field experiment held in an airport, instead of using the lidar-observed radial velocity along the aircraft approach and departure glide paths to detect the low-level wind shear, the regions of horizontal as well as vertical wind shear can be identified within a three-dimensional space by directly computing the difference in the total wind speed between adjacent points. The approach proposed in this research can be efficiently executed in a round-the-clock manner with minimal human effort. Such synthesis methods and high-quality datasets could be applied for various purposes, including the study of boundary layer development, initiation of afternoon thunderstorms, air pollutant dispersion, numerical model verification, and real-time monitoring of aviation safety in airports. Significance Statement This work introduces a new way of studying the clear-air boundary layer characteristics using high-spatial-resolution three-dimensional wind and thermodynamic fields obtained through the combined use of advanced retrieval schemes and scanning wind lidars. The proposed approach can be conducted continuously with minimal human effort to operate observational instruments. The potential applications of such synthesis methods and high-quality datasets include the investigation of convection initiation, air pollutant dispersion, and the detection of low-level wind shear in airports.

The issue of climate change in the world has become a serious problem until now. The excessive use of artificial air conditioning systems is one of the main contributors to climate problems in the world. Design solutions to help the world's climate problems through a design approach that creates optimal natural air conditioning performance. One of the things that affects the performance of natural ventilation is the placement of the opening position based on the Velocity of the airflow. Soori Bali designed by SCDA Architects was chosen as the object of study because the orientation of the building is designed to take advantage of the potential of the sea breeze as a natural ventilation strategy in its resort units. The method used is the simulation method using Autodesk CFD by evaluating several variations in the position and size of the openings placed horizontally from the left side to the right side of the building. The data collected included the airflow velocity (m/s), flow direction, and turbulence position to the layout of the room in each variation. The results of the simulation were compared to determine the most effective opening and furniture configuration configuration in supporting natural ventilation in tropical buildings. The results of the study showed that the 3 × 3 meter openings placed in the middle position of the room were able to produce an air flow of 1–3 m/s with a temperature distribution of 25–27°C, thus creating optimal passive thermal comfort in tropical buildings in accordance with the SNI 03-6572-2001 standard.

Abstract Cold water coastal upwelling is a regional phenomenon observed during the warm season along the New Jersey and Long Island (New York) coastlines and can be associated with the New York Bight sea breeze and low-level jet (LLJ). With persistent south-westerly flow, common during sea breeze conditions, cold water upwells along the New Jersey coastline, cooling sea surface temperatures (SSTs) and resulting in the development of an internal boundary layer. Using the Weather Research and Forecasting modeling system on select summertime sea breeze and LLJ events, we measure the influence of cold water coastal upwelling on the sea breeze strength, onset time, and LLJ structure. A problem in understanding cold water coastal upwelling is that satellite datasets have temporal and spatial resolution limitations that make it difficult to detect localized and episodic pockets of relatively cold water along the coastlines. To isolate the influence of upwelling on the sea breeze, we edit the input Operational Sea Surface Temperature and Ice Analysis along the New Jersey coastline to perform three experiments: 1) “GradientUpwell”, characterized by extreme cold water upwelling along coastline; 2) “NoUpwell”, where any upwelling is removed; and 3) “WarmAll”, SSTs are uniformly increased based on current SST anomalies and trends. Results show that cold water upwelling can increase the strength of the sea breeze and associated LLJ, leading to an earlier sea breeze onset and further inland sea breeze propagation. Reducing the air-sea temperature gradient by warming surface waters is demonstrated to weaken the strength of the sea breeze.

Abstract Air temperature, humidity, wind, and cloudiness are influenced by sea and land breezes (SLB). They are also the main environmental determinants of human thermal comfort or lack thereof in coastal regions, leading to heat stress. This study evaluates, for the first time, the relief from or aggravation of heat stress in the context of SLB, and it does so by introducing a novel sea breeze identification method that combines meteorologically-based criteria with changes in a comfort-related index. Considering quality-controlled observations from a coastal station near Nice (France) in 31 summer seasons from 1993 to 2023, 590 sea breeze events are identified, which occur on 54% of summer days. The majority of the events (423) are associated with increases in humidity and wind speed and provide heat relief on their onset, which is mostly in the morning, by favouring the body’s evaporative cooling, especially when air temperature decreases. In 167 events, heat aggravation is observed instead. Whether reducing or increasing air temperature, these events are characterised by increased humidity and weaker winds than the sea breezes in which relief occurs. The net result discourages the body’s convective cooling mechanisms, favouring heat stress. Results confirm the relieving value of onshore over offshore winds, especially at the beginning of the summer season in June, unveiling the complexity of SLB in the thermal comfort domain and drawing attention to a more refined vision on heat in areas affected by local winds. Graphical Abstract Graphical abstract describing the data, methodology and results of a novel sea-land breeze identification method. Applied to quality-controlled observations made at a coastal station in Nice (France) for 31 summer seasons between 1993 and 2023 ( left panel ), the method merges meteorologically-based criteria with changes in a comfort-related index (Universal Thermal Climate Index) to assess the relief and aggravation of human heat stress caused by sea-land breezes ( middle panel ). Breezes are identified as heat-relieving events when they primarily occur in the morning and at the start of summer, whereas heat aggravation occurs with events characterised by increased humidity and weaker winds ( right panel ).

Abstract The characteristics of the land and sea breeze near the west coast of Sumatra are studied using hourly 10-m wind observations from the Bengkulu Airport for the year 2018, with an emphasis on the properties of the land breeze. Spectral analysis shows that the land–sea breeze cycle is a dominant part of the overall circulation in the region, with disturbances at the diurnal frequency accounting for roughly half the overall disturbance kinetic energy. A method is presented for isolating the near-diurnal parts of the flow through a combination of high- and low-pass filtering, with land and sea breezes defined in terms of the shore-perpendicular component of the filtered winds. By this definition, a land breeze occurs each day, with a median onset time of 1900 LT, a median duration of 15 h, and a median maximum speed of 1.8 m s−1 occurring near 0200 LT. The characteristics of the land breeze are found to depend strongly on the phase of the Madden–Julian oscillation. A dependence was also found during the Asian and Australian monsoons, particularly for the onset time and maximum speed. Sea breezes occur almost every day but are much shorter (about 8.5 h) and stronger (>3 m s−1) than land breezes. Comparisons between airport observations and ERA5 surface winds show that while ERA5 accurately captures the onset time, duration, and timing of the maximum speed for sea breezes, it only captures the onset time and duration for land breezes. For both, the maximum speed is significantly underestimated. Significance Statement Detailed characteristics of tropical land and sea breezes are lacking in the literature. Utilizing 1 year of hourly wind observations from the west coast of Sumatra and a newly developed detection algorithm, we found that land and sea breezes occur essentially every day. Land breezes start just after sunset but last many hours after sunrise and reach their maximum speed almost halfway through their median 15-h duration. These properties vary intraseasonally and seasonally. Sea breezes begin around 1000 LT and are much shorter and stronger than land breezes. ERA5 does a reasonable job capturing many characteristics of the land–sea breeze circulation but underestimates the maximum wind speed in both cases.

Abstract Aerosols serve as cloud condensation nuclei, shaping the microphysical properties of cloud droplets. Aerosol effects on convective clouds are complex and remain controversial. The debate centers around the process of aerosol-induced invigoration of deep convection, a phenomenon that could significantly affect convective cloud properties but lacks robust evidence due to methodological limitations in observational approaches and questions about the robustness of modeling studies. Resolving these discrepancies is crucial for understanding how aerosols affect the atmosphere. This study examines the effects of meteorological and aerosol parameters in a weakly synoptic-driven convective environment, where the influence of aerosols may be more pronounced and observable. Daily atmospheric soundings and aerosol concentrations from several ground instruments collected during the summer of 2022 in Houston, Texas, as part of the Tracking Aerosol Convection interactions Experiment (TRACER) and Experiment of Sea Breeze Convection, Aerosols, Precipitation, and Environment (ESCAPE) field campaigns are analyzed. Statistical learning methods are applied to uncover the complex relationships between aerosols, meteorology, and convective cloud characteristics, such as cell area and echo-top height. The findings reveal that higher aerosol concentrations are associated with narrower convective cells, which we argue contradicts the idea of stronger convection with increased aerosol loading. However, once the data are clustered by the synoptic environment, the relationship between aerosol loading and convective cell area diminishes, indicating that the covariablity between synoptic-scale weather patterns, local thermodynamics, and aerosol loading makes it challenging to draw definitive conclusions about the specific impacts of aerosols on convective cloud properties.

A pilot investigation of PM10-bound atmospheric microplastics over a protected mangrove ecosystem: Role of land-sea breeze circulation in marine and terrestrial inputs.

This study aims to analyze the differences in thermal conditions between coastal and riverside settlements, focusing on variations in temperature, humidity, and wind speed during day and night. The research sites include the coastal area of Dusun Karama Tengah (seaside) and Desa Salotengnga (riverside). Measurements indicate that the coastal area experiences more extreme daytime temperature fluctuations, reaching nearly 39 °C, with nighttime temperatures remaining warm and showing noticeable variation among points. In contrast, the riverside area displays more stable temperature patterns, with nighttime temperatures ranging between 28–30 °C. Relative humidity along the coast increases consistently at night, whereas in the riverside area it is heterogeneous, varying from saturated to very dry conditions. Wind speed serves as a key differentiating factor: the coastal area is still influenced by land–sea breezes, while the riverside environment tends to be stagnant with weak natural ventilation. These findings highlight distinct thermal comfort challenges in both settings—coastal areas are prone to daytime heat stress, whereas riverside areas face nighttime discomfort due to humidity and air stagnation. The results provide a foundation for adaptive architectural and spatial design strategies responsive to local microclimatic contexts.

Abstract Current understanding of the position of nighttime convection initiation (CI) center over Hainan Island remains significantly limited. This study comprehensively clarifies what locks the position of the nighttime CI center in Hainan Island. The nighttime CI occurrence over Hainan Island requires warm and moist environmental winds, which primarily generate strong convergence in the southwestern‐to‐eastern offshore region, where nighttime CI occurrence is first locked. Concurrently, the intrinsically phase‐locked inertial oscillation of sea breezes over the South China Sea causes strong convergence between sea breezes and land breezes in the southern‐to‐eastern offshore region, where nighttime CI occurrence is second locked. Ultimately, the coupling between upper‐level easterlies and low‐level environmental winds induces strong vertical wind shear over the southwestern and southern sides of the island, where CI development is highly suppressed. These triple mechanisms collectively lock the nighttime CI center into the southeastern offshore region of Hainan Island.

This study analyzes winds over the Red Sea (17 N, 39.5 E) and consequences for the northeast African climate in early summer (May–July). As the Indian SW monsoon commences, NNW winds > 6 m/s are channeled over the Red Sea between 2000 m highlands, forming a low-level jet. Although sea surface temperatures of 30C instill evaporation of 8 mm/day and surface humidity of 20 g/kg, the air mass above the marine layer is dry and dusty (6 g/kg, 100 µg/m3). Land–sea temperature gradients drive afternoon sea breezes and orographic rainfall (~4 mm/day) that accumulate soil moisture in support of short-cycle crops such as teff. Statistical analyses of satellite and reanalysis datasets are employed to reveal the mesoscale structure and temporal response of NE African climate to marine winds via air chemistry data alongside the meteorological elements. The annual cycle of dewpoint temperature often declines from 12C to 4C during the Indian SW monsoon onset, followed by dusty NNW winds over the Red Sea. Consequences of a 14 m/s wind surge in June 2015 are documented via analysis of satellite and meteorological products. Moist convection was stunted, according to Cloudsat reflectivity, creating a dry-east/moist-west gradient over NE Africa (13–14.5 N, 38.5–40 E). Diurnal cycles are studied via hourly data and reveal little change for advected dust and moisture but large amplitude for local heat fluxes. Inter-annual fluctuations of early summer rainfall depend on airflows from the Red Sea in response to regional gradients in air pressure and temperature and the SW monsoon over the Arabian Sea. Lag correlation suggests that stronger NNW winds herald the onset of Pacific El Nino.

Understanding the variability of turbulence intensity (TI) under different wind regimes is essential for the design and safety of offshore wind turbines. The IEC Normal Turbulence Model (NTM), though widely adopted in industry, does not incorporate directional dependence or account for extreme wind events such as typhoons, which can lead to substantial underestimation of turbulence in complex offshore environments. In this study, field measurements from two coastal sites in China, Huilai and Pingtan, were analyzed. At Pingtan, two months of observations captured both normal and typhoon-affected winds, providing a unique dataset for assessing turbulence under typhoon-affected conditions. The results show that wind speeds during the typhoon-affected period were approximately 14% higher than those during normal periods. At Huilai, TI was evaluated under northeasterly and southeasterly sea breezes, revealing that the IEC NTM underestimated TI by 15–42%, with more pronounced discrepancies under northeasterly winds. Based on these findings, revised NTM parameters and correction factors are proposed for different wind conditions, enhancing the applicability of the model to offshore wind turbine design. This work underscores the importance of incorporating directional and event-specific modifications into IEC turbulence standards to ensure reliable structural assessment across diverse wind regimes.

Abstract The sea-breeze front (SBF) intruding into coastal cities can lead to sudden changes in local weather and air quality. Its structures and disturbances over the urban surface with dense tall buildings have been a challenge for numerical modeling. In this study, we present the fine-scale structures of an actual SBF simulated by mesoscale-to–large-eddy simulation (LES) models at 3-m resolution in a 15-km domain of Sendai City, Japan. The head of SBF is shown to develop remarkable three-dimensional structures in the downtown area, where it interacts strongly with the microscale turbulent flows induced by buildings. Localized strong updrafts form at the lees of high-rise buildings within a few minutes just after the passing of the SBF, as ejections emerge in urban warm air mass surrounded by the cool air mass of the sea breeze. Downdrafts in the sea breeze are seen at the windward sides of high-rise buildings and help to increase wind speed in adjacent streamwise streets. After the passage of SBF, near-surface wind speeds exhibit high-frequency fluctuations with a period of 2–3 min, in good agreement with in situ observations in the downtown area. These results demonstrate the good capabilities of the building-resolving LES of both mesoscale weather conditions and microscale turbulent flows over a large city for the prediction of urban weather and environment in the streets. Significance Statement The sea-breeze front (SBF) has significant impacts on the local weather in coastal cities around the world. It is challenging to simulate the fine-scale structures of SBF and their interactions with turbulent flows over the cities. In this study, we present an improved building-resolving numerical simulation of an actual SBF that develops fine-scale structures in the downtown area with high-rise buildings. The SBF head is shown to be strongly disturbed by buildings and interacts with urban turbulent flows, which drive local strong updrafts and vertical transports of heat. The passing SBF also leads to high-frequency fluctuations in the simulated surface wind speed, in good agreement with observations. The results are helpful for improving our understanding and prediction of the local winds at street scales during the passing of the front.

Abstract In this study, large-eddy simulations (LESs) of converging sea breezes over a peninsula are performed to investigate the effect of its orography on the ability of the model to simulate an observed event of deep convection initiation and, more generally, to understand deep convection in a regime in which both sea-breeze and mountain–plain circulations play a role. The present idealized experiments indicate that the inclusion of orography in the simulation, while of modest height (200 m), dramatically changes the simulations and allows deep convection to develop before the collision of the two sea-breeze fronts at the peninsula center. Using LES, the present study explores in detail the interaction among the sea breezes, the mountain–plain circulation, and deep convection as a function of the slope of the hill. It is found that the timing, mechanisms, and structure of convective cells are extremely sensitive to the hill slope.

Abstract The convective boundary layer (CBL) is one of the most important and variable layers in the atmosphere, yet observations of the CBL have been limited. Recent results show that the dual-polarization WSR-88D radars can observe CBL depth using differential reflectivity observations on most days with observations available every 10 min or less. We apply a CBL depth tracking method to observations from 48 WSR-88D dual polarization radars spread across CONUS for 2014 and 2022. Results indicate that mean monthly CBL depth over CONUS is smallest in December at 632 m and largest in June at 1606 m. Objective analyses of daily maximum CBL depths show large horizontal variability with synoptic and mesoscale processes contributing to this variability. CBL depths are deeper in the warm sector of midlatitude cyclones compared to surrounding regions, with some days showing anomalies in maximum daily CBL depth of over 1000 m in the warm sector. Mesoscale processes such as lake and sea breezes and precipitation also influence CBL depths. The time of maximum CBL depth shifts throughout the year, being earliest in the winter months and over an hour later in the summer months with regional variations. CBL depth increases most rapidly 1–3 h prior to local noon, with decreases in CBL depth starting 3 h after local noon. Calculating CBL depth routinely from the WSR-88D network will be valuable for air quality and aviation forecasts, model verification, and data assimilation. Significance Statement The boundary layer is the atmospheric layer that is in direct contact with Earth’s surface and is where we spend our lives. The depth of the daytime portion of the boundary layer varies from a few tens of meters early in the morning to over 1000 m by late afternoon before falling back to a shallow depth around sunset. Our ability to observe the depth of this layer has been limited, but upgrades to the U.S. national radar network have opened the door to observing this depth every 10 min on most days. We explore radar estimates of daytime boundary layer depth over 2 years and find that the depth is increased to the south and southwest of low pressure systems. We also find changes in depth from lake and sea breezes and associated with precipitation areas. These new observations allow us for the first time to study simultaneous boundary layer observations from across CONUS and thereby greatly expand our capability to understand the mechanisms that drive changes within this layer.