A Long-Term Study of Sea-Breeze Characteristics: A Case Study of the Coastal City of Adelaide

AbstractThe sea-breeze characteristics of the Adelaide, Australia, coastline have been studied by applying a sea-breeze detection algorithm to 3- and 6-hourly meteorological records of near-surface and upper-air data at Adelaide Airport from 1955 to 2007. The sea breeze is typically a westerly gulf breeze combined with a later-occurring southerly ocean breeze. Regression analysis showed a significant increasing trend in the intensity of sea breezes but not in their frequency. Over the 52-yr period, there was an average increase of 1 m s−1 in zonal and 0.7 m s−1 in meridional sea-breeze wind speed components. The annually and seasonally averaged maximum wind speeds on sea-breeze days increased significantly over the 52-yr period of the study by 0.65 m s−1 for the whole year, 0.48 m s−1 in spring, 1.02 m s−1 in summer, and 1.10 m s−1 in autumn. A comparison of hourly data for 1985–95 with those for 1996–2007 showed frequencies of sea-breeze onset times less than 4 h from sunrise increasing from 29% to 36%, durations greater than 8 h increasing from 51% to 59%, and times of maximum sea breeze between 2 and 6 h after sunrise increasing from 44% to 50%. The monthly frequency of sea breezes was found to increase by 2.8 percentage points for each degree Celsius rise in monthly average maximum air temperature at Adelaide Airport. The meridional ocean-breeze wind speed, unlike the gulf-breeze wind speed, is also correlated with maximum air temperature at Adelaide Airport.

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Opposite trends of sea-breeze speeds and gusts in Eastern Iberian Peninsula, 1961-2019

10.5194/egusphere-egu21-3411 ◽

2021 ◽

Author(s):

Shalenys Bedoya-Valestt ◽

Cesar Azorin-Molina ◽

José A. Guijarro ◽

Victor J. Sanchez-Morcillo

Keyword(s):

Wind Speed ◽

Iberian Peninsula ◽

Atmospheric Circulation ◽

Air Temperature ◽

Large Scale ◽

Sea Breeze ◽

Sea Breezes ◽

Long Term Trends ◽

Large Scale Atmospheric Circulation

<p>Long-term trends of local winds such as sea breezes have been less addressed in climate research, despite their impacts on broad environmental and socioeconomic spheres, such as weather and climate, agriculture and hydrology, wind-power industry, air quality or even human health, among many others. In a warming climate, sea breezes could be affected by changes on air temperature, as these onshore winds are thermally-driven by gradients between the sea-land air, but also by ocean-atmosphere oscillations or changes in large-scale atmospheric circulation. In the last few decades, advances in wind trends studies evidenced a recovery in global wind stilling during the last 10 years, and differences in the sign-magnitude of wind speed trends were found at seasonal-scale, suggesting the hypothetic effect of the reinforcement of local wind circulations in the warm seasons.</p><p>In this study, we analyze for the first time the long-term trends, multidecadal variability and possible drivers of the sea-breeze speeds and gusts in Eastern Iberian Peninsula during the last 58 years (1961-2019), using homogenized wind speed and gusts data from 16 meteorological stations. To identify potential sea breeze episodes, we developed a robust automated method based on alternative criteria. Our results suggest a decoupling between the declining sea-breeze speeds and the strengthening of the maximum gusts for much of the 1961-2019 period at annual, seasonal and monthly scales, but differences based on locations were also found. Because sea breeze changes can be driven by multiple complex factors (i.e. land use changes, land-sea air temperature gradient, complex orography, etc.), the attribution of causes is challenging. To better understand the causes behind the opposite trends between sea-breeze speeds and gusts, we investigate the effect of e.g. the changes in large-scale atmospheric circulation or physical-local factors.</p>

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Regionalization of Ukraine based on the influence of extreme values of maximum air temperature during warm and cold periods of the year

Ukrainian hydrometeorological journal ◽

10.31481/uhmj.22.2018.05 ◽

2018 ◽

pp. 46-56

Author(s):

S. V. Savchuk ◽

N. N. Yuvchenko ◽

V. E. Timofeev

Keyword(s):

Atmospheric Circulation ◽

Air Temperature ◽

Extreme Values ◽

Warm Period ◽

Synoptic Situation ◽

The South ◽

Cool Period ◽

Near Surface ◽

Average Maximum ◽

Maximum Air Temperature

Based on the data of maximum daily near-surface air temperature (MSAT) taken from 186 meteorological stations of Ukraine the parameters of extremality with relation to maximum air temperature for different time periods as well as deviations between them during cold and warm periods of the year were calculated. Regionalization of Ukraine was carried out in order to identify climate-vulnerable regions by means of comparison, overlapping and match of the areas with the highest values towards selected extremality thresholds. The conclusion about general increase in extremality over the last decade with relation to a climatic standard is made, the areas with the greatest vulnerability are outlined, and the areas with increase in extremality degree are identified. During both periods of the year certain areas in the southern, central and eastern parts of Ukraine are considered, based on maximum air temperature data, as the most vulnerable ones. During both periods of the year over 2001-2010, as compared to 1991-2000, increase of recurrence of extreme values of average maximum of air temperature was observed: in March and December during the cold period and also from May to July, and in case of EHMP event – in August. Distribution of maximum air temperature of the EHMP category, in comparison to the category of extreme values, specifies and localizes the regions with the greatest vulnerability. The areas of the highest vulnerability during the cool period comprise the extreme west, south-western and southern regions and during the warm period – southern, south-eastern regions and the extreme east of Ukraine. The spatial distribution of the extreme values of the MSAT for the warm period has a predominantly meridional orientation. During both periods of the year regions in the south (areas of Black Sea region, Crimea, boundary subregions in the south) areas in the east and center of Ukraine affected by extreme MSAT values are the most vulnerable; in 2010-2014 this influence intensified. Increase in the vulnerability based on the maximum air temperature occurs on the background of certain changes in the atmospheric circulation, under conditions of anticyclonic fields prevalence throughout the year along with increase of the temporal exposure to the elementary synoptic process. On the other hand, the aforementioned increase of recurrence of extreme hydrometeorological phenomena is a consequence of sharp changes of synoptic situation, which is especially the case after a period of settled weather. The conclusion that atmospheric circulation is a main agent responsible for extreme weather and that it is not studied completely so far was made.

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Direct radiative effect of the Russian wildfires and its impact on air temperature and atmospheric dynamics during August 2010

Atmospheric Chemistry and Physics ◽

10.5194/acp-14-1999-2014 ◽

2014 ◽

Vol 14 (4) ◽

pp. 1999-2013 ◽

Cited By ~ 34

Author(s):

J. C. Péré ◽

B. Bessagnet ◽

M. Mallet ◽

F. Waquet ◽

I. Chiapello ◽

...

Keyword(s):

Optical Properties ◽

Wind Speed ◽

Eastern Europe ◽

Air Temperature ◽

Air Entrainment ◽

Atmospheric Dynamics ◽

Horizontal Wind ◽

Satellite Measurements ◽

Near Surface ◽

Aerosol Plume

Abstract. In this study, we investigate the shortwave aerosol direct radiative forcing (ADRF) and its feedback on air temperature and atmospheric dynamics during a major fire event that occurred in Russia during August 2010. The methodology is based on an offline coupling between the CHIMERE chemistry-transport and the Weather Research and Forecasting (WRF) models. First, simulations for the period 5–12 August 2010 have been evaluated by using AERONET (AErosol RObotic NETwork) and satellite measurements of the POLarization and Directionality of the Earth's Reflectance (POLDER) and the Cloud-Aerosol LIdar with Orthogonal Polarization (CALIOP) sensors. During this period, elevated POLDER aerosol optical thickness (AOT) is found over a large part of eastern Europe, with values above 2 (at 550 nm) in the aerosol plume. According to CALIOP observations, particles remain confined to the first five kilometres of the atmospheric layer. Comparisons with satellite measurements show the ability of CHIMERE to reproduce the regional and vertical distribution of aerosols during their transport from the source region. Over Moscow, AERONET measurements indicate an important increase of AOT (340 nm) from 0.7 on 5 August to 2–4 between 6 and 10 August when the aerosol plume was advected over the city. Particles are mainly observed in the fine size mode (radius in the range 0.2–0.4 μm) and are characterized by elevated single-scattering albedo (SSA) (0.95–0.96 between 440 and 1020 nm). Comparisons of simulations with AERONET measurements show that aerosol physical–optical properties (size distribution, AOT, SSA) have been well simulated over Moscow in terms of intensity and/or spectral dependence. Secondly, modelled aerosol optical properties have been used as input in the radiative transfer code of WRF to evaluate their direct radiative impact. Simulations indicate a significant reduction of solar radiation at the ground (up to 80–150 W m−2 in diurnal averages over a large part of eastern Europe due to the presence of the aerosol plume. This ADRF causes an important reduction of the near-surface air temperature between 0.2 and 2.6° on a regional scale. Moscow has been affected by the aerosol plume, especially between 6 and 10 August. During this period, aerosol causes a significant reduction of surface shortwave radiation (up to 70–84 W m−2 in diurnal averages) with a moderate part (20–30%) due to solar absorption within the aerosol layer. The resulting feedbacks lead to a cooling of the air up to 1.6° at the surface and 0.1° at an altitude of 1500–2000 m (in diurnal averages), that contribute to stabilize the atmospheric boundary layer (ABL). Indeed, a reduction of the ABL height of 13 to 65% has been simulated during daytime in presence of aerosols. This decrease is the result of a lower air entrainment as the vertical wind speed in the ABL is shown to be reduced by 5 to 80% (at midday) when the feedback of the ADRF is taken into account. However, the ADRF is shown to have a lower impact on the horizontal wind speed, suggesting that the dilution of particles would be mainly affected by the weakening of the ABL development and associated vertical entrainment. Indeed, CHIMERE simulations driven by the WRF meteorological fields including this ADRF feedback result in a large increase in the modelled near-surface PM10 concentrations (up to 99%). This is due to their lower vertical dilution in the ABL, which tend to reduce model biases with the ground PM10 values observed over Moscow during this specific period.

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Exposure-Dependent Variations in Air Temperature and Humidity on the Moraine of the Aavatsmark Glacier (Nw Spitsbergen) in the Summer Season of 2010

Bulletin of Geography Physical Geography Series ◽

10.2478/v10250-012-0004-7 ◽

2012 ◽

Vol 5 (1) ◽

pp. 57-75

Author(s):

Andrzej Araźny ◽

Rajmund Przybylak

Keyword(s):

Wind Speed ◽

Air Temperature ◽

Weather Conditions ◽

Active Surface ◽

Summer Season ◽

Lateral Moraine ◽

Near Surface ◽

Mean Values ◽

Temperature And Humidity ◽

Surface Air Layer

Abstract The article presents results of research on the development of air temperature and relative humidity at a height of 5 cm above the active surface of the terminal lateral moraine of the Aavatsmark Glacier, relative to its exposure in the summer season of 2010. Variations in the two conditions were analysed for five measurement sites situated on northerly (SN), easterly (SE), southerly (SS) and westerly (SW) slopes, as well as on the flat top surface of the moraine (STop), in different weather conditions. The article also includes a temperature and humidity stratification in the near surface air layer (5-200 cm) above the moraine. The issues were investigated for mean values from the whole period of research, as well as for individual days demonstrating distinct degrees of cloudiness and wind speed.

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CORRELATION COMMUNICATION BETWEEN METEOROLOGICAL PARAMETERS AT EXTREME VALUES OF MAXIMUM AIR TEMPERATURES

Hydrology, hydrochemistry and hydroecology ◽

10.17721/2306-5680.2020.1.11 ◽

2020 ◽

pp. 101-112

Author(s):

S.V. Savchuk ◽

V.E. Timofeev ◽

O.A. Shcheglov ◽

V.A. Artemenko ◽

I.L. Kozlenko

Keyword(s):

Air Temperature ◽

Meteorological Parameters ◽

Extreme Values ◽

Daily Temperature ◽

Sea Level Pressure ◽

Maximum Daily Temperature ◽

The North ◽

Air Temperatures ◽

Average Maximum ◽

Maximum Air Temperature

The object of the study is the maximum daily air temperature during the months of the year over 1991-2016 by the data of 186 meteorological stations of Ukraine. Extreme values of the maximum daily temperature equal to or exceeded their 95th (Tmax95p and above, ºС) percentile were taken as extreme. The article sets the dates (137 cases) of extreme values of maximum air temperature on more than 60 % of the territory. For these dates, 13 meteorological parameters were selected: average, minimum, and maximum air temperatures; average, minimum and maximum relative humidity; station and sea-level pressure; average, maximum (from 8 synoptic hours) wind speed; rainfall; height of snow cover. The purpose of this work is to determine the correlation coefficient (K), in particular, statistically significant (K≤-0.6, K≥0.6), on these dates between selected meteorological parameters at 186 meteorological stations of Ukraine for 1991-2013. The density of the cases of statistically significant dependence between the meteorological parameters in extremely warm days in separate seasons is determined. In extremely warm days, meteorological parameters and areas with statistically significant correlations at K≤-0.6 were detected: T and F (focally in southern and some western regions with significant density) − in winter; T and F (with the highest density ubiquitous or almost ubiquitous), P and V (in a large number of regions, usually west or right-bank, but with less frequency) − in the transition seasons, and in the autumn between − T and F (in the south with smaller density) and P and F (in some areas of the north, northwest, west, lower east). In all seasons, such a correlation between other meteorological parameters had a focal distribution, usually with a smaller density. In these days, a focal distribution with a small frequency of dependencies at K≥0.6 was found between the meteorological parameters detected (F and V in transition seasons, T and F in winter), except for similar ones. However, such dependence is observed between T and V in some regions in winter and autumn and in some areas of south, southeast, east with a smaller density. The study of the maximum daily temperature is relevant, because from the level of natural hydrometeorological phenomena it is accompanied by dangerous phenomena, negatively affecting the weather dependent industries.

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Toward Improved Forecasts of Sea-Breeze Horizontal Convective Rolls at Super High Resolutions. Part II: The Impacts of Land Use and Buildings

Monthly Weather Review ◽

10.1175/mwr-d-14-00230.1 ◽

2015 ◽

Vol 143 (5) ◽

pp. 1873-1894 ◽

Cited By ~ 8

Author(s):

Guixing Chen ◽

Xinyue Zhu ◽

Weiming Sha ◽

Toshiki Iwasaki ◽

Hiromu Seko ◽

...

Keyword(s):

Land Use ◽

Sea Breeze ◽

Secondary Flows ◽

Wake Flow ◽

Near Surface ◽

Sea Breezes ◽

Regional Features ◽

Secondary Circulations ◽

Forecast Models ◽

Convective Rolls

Abstract Horizontal convective rolls form in coastal areas around Sendai Airport during sea-breeze events. Using a building-resolving computational fluid dynamics model nested in an advanced forecast system with a data assimilation scheme, the authors perform a series of sensitivity experiments to investigate the impacts of land use and buildings on these rolls. The results show that the roll positions, intensities, and structures are significantly affected by variations in land use and the presence of buildings. Land-use heterogeneity is responsible for generating rolls with evident regional features. Major rolls tend to develop downwind of warm surfaces, and they dominate over neighboring rolls; thus, a heterogeneity-scale mode is imposed on the inherent roll wavelength. The roll’s rapid growth is attributable to warm surfaces that initiate a strong coupling among turbulent thermals, convective updrafts, pressure perturbations, and secondary flows in sea breezes. The heterogeneity-induced features differ considerably from the nearly homogeneous features that form over uniform surfaces. Additionally, the wake flow behind buildings helps organize near-surface warm air into streamwise bands that drive streaky ejections. The building-induced turbulence acts to modify secondary flows and displace roll updrafts toward building wakes. Such effects are most effective over villages with scattered houses that are aligned with the ambient wind. Building signatures are elongated in downwind open areas due to sustained secondary circulations. An analysis of turbulent kinetic energy shows that both land use and buildings regulate energy generation and transport, resulting in a clear response in roll growth. Thus, including complex surfaces in forecast models helps determine detailed characteristics and structures of roll convection over coastal regions.

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The Large-eddy Observatory Voitsumra Experiment 2019 (LOVE19) with high-resolution, spatially-distributed observations of air temperature, wind speed, and wind direction from fiber-optic distributed sensing, towers, and ground-based remote sensing

10.5194/essd-2020-392 ◽

2021 ◽

Author(s):

Karl Lapo ◽

Anita Freundorfer ◽

Antonia Fritz ◽

Johann Schneider ◽

Johannes Olesch ◽

...

Keyword(s):

Remote Sensing ◽

Boundary Layer ◽

Wind Speed ◽

Air Temperature ◽

Wind Direction ◽

Fiber Optic ◽

Layer Structure ◽

Distributed Sensing ◽

Near Surface ◽

Large Eddy

Abstract. The weak-wind Stable Boundary Layer (wwSBL) is poorly described by theory and breaks basic assumptions necessary for observations of turbulence. Understanding the wwSBL requires distributed observations capable of separating between submeso and turbulent scales. To this end, we present the Large Eddy Observatory, Voitsumra Experiment 2019 (LOVE19) which featured 1350 m of fiber optic distributed sensing (FODS) of air temperature and wind speed, as well as an experimental wind direction method, at scales as fine as 1 s and 0.127 m in addition to a suite of point observations of turbulence and ground-based remote sensing. Additionally, flights with a fiber optic cable attached to a tethered balloon provide an unprecedented detailed view of the boundary layer structure with a resolution of 0.254 m and 10 s between 1–200 m height. Two examples are provided demonstrating the unique capabilities of the LOVE19 data for examining boundary layer processes: 1) FODS observations between 1m and ~200 m height during a period of gravity waves propagating across the entire boundary layer and 2) tracking a near-surface, transient submeso structure that causes an intermittent burst of turbulence. All data can be accessed at Zenodo through the DOI https://doi.org/10.5281/zenodo.4312976 (Lapo et al., 2020a).

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Outdoor thermal performance simulation in campus area during the dry season, Yogyakarta

Journal of Advanced Civil and Environmental Engineering ◽

10.30659/jacee.2.1.15-24 ◽

2019 ◽

Vol 2 (1) ◽

pp. 15

Author(s):

Hasti Widyasamratri ◽

Arif Kusumawanto ◽

Fadhilla Tri Nugrahaini

Keyword(s):

Wind Speed ◽

Air Temperature ◽

Thermal Performance ◽

Meteorological Parameters ◽

Anthropogenic Activities ◽

Surface Air Temperature ◽

Dry Season ◽

Performance Simulation ◽

Near Surface ◽

Significant Area

The outdoor thermal performance reflects the microclimate condition in any significant area. This study simulated the thermal performance with measured and modeled three meteorological parameters, air temperature (Ta), relative humidity (RH), and wind speed in the dry season tropical city. The research focused on thermal performance simulation and distribution, here, we were neglecting anthropogenic activities as the heat source. The result showed that there were different ranges between a measured and simulated value of Ta, RH, and wind speed. The highest Ta difference between measure and simulation occurred at 11 AM, which was 1.97⸰C. The highest difference of RH occurred at 13 PM (26.75%), and the highest different of wind speed was at 11 AM (0.37 m/s) respectively. The heat distribution in the focus area was influenced by the solar direction which impacted the ground and near-surface air temperature.

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Trends of Changes of Maximum Air Temperature in Ukraine as an Impact Factor on Population Health

Man and Environment. Issues of Neoecology ◽

10.26565/1992-4224-2020-33-01 ◽

2020 ◽

Keyword(s):

Population Health ◽

Air Temperature ◽

Thermal Regime ◽

Climate Changes ◽

System Analysis ◽

Global Climate ◽

Maximum Temperature ◽

Air Temperatures ◽

Average Maximum ◽

Maximum Air Temperature

Purpose. The aim of this research is detection of trends of changes (according to fact and scenario data) of extreme air temperature as a component of thermal regime in different regions of Ukraine because of global climate change. Methods. System analysis, statistical methods. Results. Time distribution of maximum air temperature regime characteristics based on results of observations on the stations located in different regions of Ukraine during certain available periods: Uzhgorod (1946-2018), Kharkiv (1936-2005), Оdessа (1894-2005), аnd also according to scenarios of low (RCP2.6), medium (RCP4.5) and high (RCP8.5) levels of greenhouse gases emissions. Meanwhile, air temperature ≥ 25°С was considered high (days with maximum temperature within 25,0-29,9°С are hot), ≥ 30°С was considered very high (days with such temperature are abnormaly hot). Trends of changes of extreme air temperatures were identified as a component of thermal regime in different regions of Ukraine within global climate changes. Dynamics of maximum air temperature and its characteristics in ХХ and beginning of ХХІ centuries were researched. Expected time changes of maximum air temperature and number of days with high temperature during 2021-2050 were analyzed by RCP2.6, RCP4.5 and RCP8.5 scenarios. There were identified the highest day air temperatures possible once in a century and also possibility of maximum day temperature more than 30°С by RCP4.5 scenario. Well-timed prediction of climate changes will help evaluate their impact on human and natural systems which will be useful for development and taking preventive measures towards minimization of negative influence of such changes. Conclusions. Processes of climate warming in Ukraine are activating. There was determined a strong trend on increasing of average maximum of air temperature in winter with speed 0.17-0,39 degrees centigrade/10 years. According to climatic norm this index mainly increased mostly (up to 3,3 degrees centigrade) in January in North-East of the country. In future such anomalies will grow. Determination of correlation between climate and health is the base for taking protective measures against perils for population health connected with climate.

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Idealized WRF model sensitivity simulations of sea breeze types and their effects on offshore windfields

Atmospheric Chemistry and Physics Discussions ◽

10.5194/acpd-12-15837-2012 ◽

2012 ◽

Vol 12 (6) ◽

pp. 15837-15881 ◽

Cited By ~ 3

Author(s):

C. J. Steele ◽

S. R. Dorling ◽

R. von Glasow ◽

J. Bacon

Keyword(s):

Wind Speed ◽

Wind Energy ◽

Wind Farm ◽

Wrf Model ◽

Sea Breeze ◽

Offshore Wind ◽

Eastern Coast ◽

State University ◽

Sea Breezes ◽

Gradient Wind

Abstract. The behaviour and characteristics of the marine component of sea breeze cells have received little attention relative to their onshore counterparts. Yet there is a growing interest and dependence on the offshore wind climate from, for example, a wind energy perspective. Using idealized model experiments, we investigate the sea breeze circulation at scales which approximate to those of the Southern North Sea, a region of major ongoing offshore wind farm development. We also contrast the scales and characteristics of the pure and the little known corkscrew and backdoor sea breeze types, where the type is pre-defined by the orientation of the synoptic scale flow relative to the shoreline. We find, crucially, that pure sea breezes, in contrast to corkscrew and backdoor types, can lead to substantial wind speed reductions offshore and that the addition of a second eastern coastline emphasises this effect through generation of offshore "calm zones". The offshore extent of all sea breeze types is found to be sensitive to both the influence of Coriolis acceleration and to the boundary layer scheme selected. These extents range, for example for a pure sea breeze produced in a 2 m s−1 offshore gradient wind, from 10 km to 40 km between the Mellor-Yamada-Nakanishi-Niino and the Yonsei State University schemes, respectively. The corkscrew type restricts the development of a backdoor sea breeze on the eastern coast and is also capable of traversing a 100 km offshore domain even under high gradient wind speed (>15 m s−1) conditions. Realistic variations in sea surface skin temperature during the sea breeze season do not significantly affect the circulation, suggesting that a thermal contrast is only needed as a precondition to the development of the sea breeze. We highlight how sea breeze impacts on circulation need to be considered in order to improve the accuracy of assessments of the offshore wind energy climate.

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