scholarly journals Lake and Land Breezes at a Mediterranean Artificial Lake: Observations in Alqueva Reservoir, Portugal

Atmosphere ◽  
2021 ◽  
Vol 12 (5) ◽  
pp. 535
Author(s):  
Carolina Purificação ◽  
Miguel Potes ◽  
Gonçalo Rodrigues ◽  
Rui Salgado ◽  
Maria João Costa
Keyword(s):  
Thermal Gradient ◽  
Land Breeze ◽  
Lake Breeze ◽  
Floating Platform ◽  
Night Time ◽  
Artificial Lake ◽  
Local Climate ◽  
Main Driver ◽  
Alqueva Reservoir ◽  
Land Breezes

The Alqueva reservoir, in the Southeast of Portugal, has significantly changed the landscape of the region, with impacts also on the local climate, as documented in this manuscript, namely the thermal circulation in the form of lake and land breezes. Taking advantage of three strategic meteorological stations, two installed at the shores and another on a floating platform located near the center of the reservoir, a detailed analysis of lake and land breeze occurrences during two years is presented in this study. The thermal gradient between the reservoir and the surroundings is the main driver for the breeze development and the meteorological stations placed in opposite sides of the reservoir allow to establish the criteria in order to detect lake and land breezes. The results showed more land breeze than lake breeze occurrences, in line with the more negative thermal gradient between shores and reservoir in the annual cycle. Lake breezes are more frequent in summer months during daytime and land breezes in turn are more frequent in winter months during night-time.

scholarly journals Breeze effects at a large artificial lake: summer case study

2018 ◽  
Vol 22 (10) ◽  
pp. 5191-5210 ◽  
Author(s):  
Maksim Iakunin ◽  
Rui Salgado ◽  
Miguel Potes
Keyword(s):  
Western Europe ◽  
Atmospheric Model ◽  
Lake Breeze ◽  
Artificial Lake ◽  
Natural Lakes ◽  
Alqueva Reservoir ◽  
The Difference ◽  
Surrounding Areas ◽  
The Impact

Abstract. Natural lakes and big artificial reservoirs can affect the weather regime of surrounding areas but, usually, consideration of all aspects of this impact and their quantification is a difficult task. The Alqueva reservoir, the largest artificial lake in western Europe, located on the south-east of Portugal, was filled in 2004. It is a large natural laboratory that allows the study of changes in surface and in landscape and how they affect the weather in the region. This paper is focused on a 3-day case study, 22–24 July 2014, during which an intensive observation campaign was carried out. In order to quantify the breeze effects induced by the Alqueva reservoir, two simulations with the mesoscale atmospheric model Meso-NH coupled to the FLake freshwater lake model has been performed. The difference between the two simulations lies in the presence or absence of the reservoir on the model surface. Comparing the two simulation datasets, with and without the reservoir, net results of the lake impact were obtained. Magnitude of the impact on air temperature, relative humidity, and other atmospheric variables are shown. The clear effect of a lake breeze (5–7 m s−1) can be observed during daytime on distances up to 6 km away from the shores and up to 300 m above the surface. The lake breeze system starts to form at 09:00 UTC and dissipates at 18:00–19:00 UTC with the arrival of a larger-scale Atlantic breeze. The descending branch of the lake breeze circulation brings dry air from higher atmospheric layers (2–2.5 km) and redistributes it over the lake. It is also shown that despite its significant intensity the effect is limited to a couple of kilometres away from the lake borders.

The allometric scaling of thermal emissions from temperate and tropical cities

2020 ◽  
Author(s):  
Mukhtar Abdulrasheed
Keyword(s):  
Power Law ◽  
Urban Areas ◽  
Allometric Scaling ◽  
Total Population ◽  
Thermal Emission ◽  
Surprising Result ◽  
Night Time ◽  
Population Total ◽  
Local Climate ◽  
Thermal Emissions

<p><strong>ABSTRACT</strong></p><p>Cities around the world develop energy balances that are different to their surroundings. This study examines the application of allometric scaling to the thermal emission of cities in temperate and tropical regions. Overpasses of UK and Nigeria of the Moderate Resolution Imaging Spectroradiometer (MODIS), covering the period between 2000 and 2017 were sampled to examine the seasonal variability in night-time clear-sky upwelling long-wave energy for selected cities of the two countries. Total (area-integrated) emitted energy was calculated per city and interpreted by looking for ‘allometric’ (power law) scaling against the total population of the urban areas. Both sets of cities produce strong correlations (R<sup>2 </sup>³ 0.8 and R<sup>2</sup>≥0.7) of log (total emission) against log (population). Total night-time emitted energy is found to scale sub-linearly (i.e. with power law index < 1) with population on both countries. However, the slope derived from UK allometry (0.85 ± 0.03) is quite different from that derived for cities in Nigeria (0.4 ± 0.05). When scaled against log (city area), both sets of cities produce linear scalings, demonstrating that the total area of built surface is a more general predictor of thermal emissions than total population, a surprising result given the differences in built form in the two sets of cities. These results are robust to the method chosen to delineate the city boundary. We further investigate the factors underlying these allometric relationships using Local Climate Zone (LCZ) classifications.    </p>

scholarly journals Breeze effects at a large artificial lake: summer case study

2018 ◽  
Author(s):  
Maksim Iakunin ◽  
Rui Salgado ◽  
Miguel Potes
Keyword(s):  
Western Europe ◽  
Atmospheric Model ◽  
Artificial Lake ◽  
Natural Lakes ◽  
Input Surface ◽  
Alqueva Reservoir ◽  
Mesoscale Atmospheric Model ◽  
Surrounding Areas ◽  
The Impact

Abstract. Natural lakes and big artificial reservoirs could affect the weather regime of surrounding areas but usually it is difficult to track all aspects of this impact and evaluate its magnitude. Alqueva reservoir, the largest artificial lakes in Western Europe located on the South-East of Portugal, was filled in 2004. This makes it a large laboratory and allows to study the changes in hydrological and geological structures and how they affect the weather in the region. This paper is focused on a case study of the 3 days period of 22–24 July 2014. In order to quantify the breeze effects induced by Alqueva reservoir two simulations with the mesoscale atmospheric model Meso-NH coupled to FLake freshwater lake scheme has been done. The principal difference of this two simulations is in the presence of the reservoir in the input surface data. Comparing two simulations datasets: with and without reservoir, net results of the lake impact were obtained. Magnitude of the impact on the air temperature, relative humidity, and other atmospheric parameters is shown. Clear effect of a lake breeze (5–7 m/s) can be observed during the daytime on the distances up to 6 km away from the shores and up to 300 m over the lake surface. Breeze system starts to form at 9:00 UTC and dissipates at 18:00–19:00 UTC with the arrival of major Atlantic breeze system. It induces specific air circulation that captures the dry air from the upper atmosphere (2–2.5 km) which follows the downstream and redistributes over the lake. It is also shown that the although the impact can be relatively intensive, its area is limited by several kilometers away from the lake borders.

A 7-Yr Climatological Study of Land Breezes over the Florida Spaceport

2005 ◽  
Vol 44 (3) ◽  
pp. 340-356 ◽  
Author(s):  
Jonathan L. Case ◽  
Mark M. Wheeler ◽  
John Manobianco ◽  
Johnny W. Weems ◽  
William P. Roeder
Keyword(s):  
Onset Time ◽  
Sea Breeze ◽  
Land Breeze ◽  
Density Currents ◽  
East Central ◽  
Central Florida ◽  
Onshore Flow ◽  
Kennedy Space ◽  
Horizontal Temperature Gradients ◽  
Land Breezes

Abstract Seven years of wind and temperature data from a high-resolution network of 44 towers at the Kennedy Space Center and Cape Canaveral Air Force Station were used to develop an objective method for identifying land breezes, which are defined as seaward-moving wind shift lines in this study. The favored meteorological conditions for land breezes consisted of surface high pressure in the vicinity of the Florida peninsula, mainly clear skies, and light synoptic onshore flow and/or the occurrence of a sea breeze during the afternoon preceding a land breeze. The land breeze characteristics are examined for two events occurring under different weather regimes—one with light synoptic onshore flow and no daytime sea breeze, and another following a daytime sea breeze under a prevailing offshore flow. Land breezes were found to occur over east-central Florida in all months of the year and had varied onset times and circulation depths. Land breezes were most common in the spring and summer months and least common in the winter. The average onset times were ∼4–5 h after sunset from May to July and ∼6.5–8 h after sunset from October to January. Land breezes typically moved from the west or southwest during the spring and summer, from the northwest in the autumn, and nearly equally from all directions in the winter. Shallow land breezes (<150-m depth) were typically not associated with the afternoon sea breeze and behaved like density currents, exhibiting the largest temperature decreases and latest onset times. Deep land breezes (>150-m depth) were most often preceded by an afternoon sea breeze, had the smallest horizontal temperature gradients, and experienced a mean onset time that is 4 h earlier than that of shallow land breezes.

scholarly journals Resonant Diurnal Oscillations and Mean Alongshore Flows Driven by Sea/Land Breeze Forcing in the Coastal Southern California Bight

2013 ◽  
Vol 43 (3) ◽  
pp. 616-630 ◽  
Author(s):  
SungHyun Nam ◽  
Uwe Send
Keyword(s):  
Heat Flux ◽  
Southern California ◽  
Southern California Bight ◽  
Land Breeze ◽  
Resonant Response ◽  
Strong Response ◽  
Cross Sectional ◽  
Eddy Heat Flux ◽  
Diurnal Wind ◽  
Land Breezes

Abstract This study presents observations of the cross-sectional structure of resonant response to sea/land breezes (SLBs) off Huntington Beach (HB) in the Southern California Bight (SCB). A resonant response to local diurnal wind stress fluctuations associated with SLB forcing occurs intermittently and produces strong diurnal oscillations of flow and temperature resulting from enhanced work of the diurnal local wind on the sea surface. At nighttime (daytime), a coherent cross-sectional circulation with offshore (onshore) currents in the surface layer (upper 15 m) and onshore (offshore) currents in the intermediate layer around 20 m are generated, with a three-layered vertical structure on the outer shelf. The authors find a net cross-shore eddy heat flux (net cooling of nearshore water) during the period of strong response to SLB, that is, a rectified mean heat flux and steeper isotherms resulting from the diurnal SLB fluctuations. The steepened mean isotherms are also found to be in thermal–wind balance with intensified mean equatorward flow, which thus can also be generated by the resonant SLB dynamics. Similar rectified onshore transport of other quantities is expected, relevant for biogeochemical processes. The distribution of maximum diurnal kinetic energy in time and across the shelf supports the concept that subinertial shears create the sufficient condition for resonant response to SLB forcing.

scholarly journals The seasonal characteristics of the breeze circulation at a coastal Mediterranean site in South Italy

2010 ◽  
Vol 4 (1) ◽  
pp. 47-56 ◽  
Author(s):  
S. Federico ◽  
L. Pasqualoni ◽  
A. M. Sempreviva ◽  
L. De Leo ◽  
E. Avolio ◽  
...  
Keyword(s):  
Surface Temperature ◽  
Land Surface Temperature ◽  
Land Surface ◽  
Large Scale ◽  
Land Breeze ◽  
Breeze Circulation ◽  
Local Circulation ◽  
Coastal Site ◽  
Local Climate ◽  
Hourly Data

Abstract. We present a study on the characteristics of the sea breeze flow at a coastal site located in the centre of the Mediterranean basin at the southern tip of Italy. This study is finalized to add new data on breeze circulations over a narrow peninsula and present a unique experimental coastal site at about 600 m from the coastline in a flat open area at the foot of a mountain chain located in a region of complex orography. We study the seasonal behaviour of the sea-land breeze circulation by analysing two years of hourly data of wind speed and direction, temperature, radiation and relative humidity from a surface meteorological station, eighteen-months data from a wind profiler, and two-year data from the ECMWF analysis. Results show that breezes dominate the local circulation and play a major role for the local climate. They are modulated by the season, through the sea-land temperature difference and the large-scale flow. The large-scale forcing acts in phase with the diurnal breeze and opposes the nocturnal breeze. In summer, the daytime difference between the land surface temperature and the SST (Sea Surface Temperature) reaches its maximum, while the nigh-time difference has its minimum. This causes a strong, frequent and intense diurnal breeze and a weak nocturnal breeze. In winter and fall the nocturnal difference between the sea and land surface temperature reaches a maximum value, while the diurnal difference is at its minimum value. This causes a strong, frequent and intense nocturnal breeze despite of the large-scale forcing that is usually opposed to local-scale flow.

scholarly journals Diurnal Cycle of Convection in the Peruvian Highlands

2019 ◽  
Author(s):  
Eleazar Chuchón Angulo ◽  
Augusto Pereira Filho
Keyword(s):  
Temporal Evolution ◽  
Northern Region ◽  
Land Breeze ◽  
Data Series ◽  
Lake Breeze ◽  
Lake Titicaca ◽  
Rain Gauges ◽  
Mountain Valley ◽  
Titicaca Basin ◽  
Spatio Temporal

This manuscript examines from the diurnal convection cycle (CDC) to the interdecadal variability in the region of the Peruvian Altiplano (RAP). Currently, estimating precipitation using satellites is an alternative which can be used to study the spatio-temporal evolution of precipitation systems. Herein CPC data Morphing technique - CMORPH (Joyce et al, 2004) was used between 2002 and 2014 to analyze the CDC in RAP. The CMOPRH data were compared with rainfall data series measured by rain gauges of meteorological stations (EMS) in the RAP. The results indicate that the CDC shows high variability in the Titicaca Basin and is associated with patterns of lake breeze (day), land breeze (night) and mountain - valley circulation. The CDC starts at 1800 HL (local time) in the northern region of Lake Titicaca, lasting between 2 h and 6 h, and most of 2000 HL. The CDC over the dry surface (ST) of Titicaca Basin starts early at around 1200 HL, lasting 4 h to 7 h, and maximum at 1800 HL.

ANALISIS ANGIN DANAU DI DAS LARONA, SULAWESI SELATAN

2012 ◽  
Vol 13 (1) ◽  
pp. 13
Author(s):  
Findy Renggono
Keyword(s):  
Electric Power ◽  
Water Availability ◽  
Land Breeze ◽  
Large Lakes ◽  
Local Climate ◽  
Surface Data ◽  
Rain Fall

Karakteristik cuaca di DAS Larona sangat penting untuk diketahui karena terkait dengan ketersediaan air danau sebagai sumber utama penggerak turbin pembangkit listrik di wilayah tersebut. Keberadaan tiga danau yang berada di dalam DAS sangat memengaruhi kondisi cuaca lokal. Data permukaan tahun 2009-2010 dari 9 lokasi di sekitar danau digunakan untuk melihat kemunculan angin danau. Hasil analisis menunjukkan adanya perubahan arah angin pada siang hari di lokasi- okasi yang terletak dekat dengan tepi danau. Kejadian hujan yang muncul pun berkorelasi dengan angin yang berhembus dari arah danau.Study of climate characteristic around Larona watershed is very important as it is associated with water availability on the lakes which is used to drive turbines of Hydro electric power. The three large lakes inside the watershed are a great contributor for affecting local climate. Surface data from nine locations near the lakes were  nalyzed to reveal the existence of lake-land wind. The result shows that the effects of lakeland breeze were found on the location near the lake beach. The lake-land breeze occurrence was also correlated with rain fall over the area.

Analysis for Influence upon Local Climate Factors of Reservoir Area of Hydropower Station after Water Storage

2012 ◽  
Vol 212-213 ◽  
pp. 245-252 ◽  
Author(s):  
Wen Yong Wang ◽  
Wen Liu ◽  
Xiao Juan Ma
Keyword(s):  
Numerical Model ◽  
Water Storage ◽  
Concentration Field ◽  
Water Area ◽  
Atmospheric Pollutants ◽  
Hydropower Station ◽  
Land Breeze ◽  
Climate Factors ◽  
Local Climate ◽  
Average Temperature

An artificial reservoir will be formed at the dam upstream in a large hydropower station after the station put into use, and with water area expanding, the local climate will change. This paper takes mesoscale meteorological numerical model WRF to simulate a certain hydropower station in Sichuan to obtain the impacting situation of the local climate after the water storage. The result indicates as follows: firstly, the wind field has been greatest changed after the water storage. Except in the winter, we can found obvious lake-land breeze in the spring and the summer and the flow field is very evident; secondly, the temperature is rising or falling; except for a little change in the spring, the average temperature falls 1.27°C in the summer but rises at 1.28°C in the winter. In addition, the humidity around the reservoir is changed distinctly; the average humid degree rises mostly at 4.56% in the winter, moderately at 2.25% in the spring but a little change at 0.94% in the summer. It is since the climate factors have been changed that the concentration field of atmospheric pollutants which generated by the industrial and mining enterprises around the reservoir has been changed at all.

scholarly journals Summertime winds and direct cyclonic circulation: observations from Lake Geneva

1996 ◽  
Vol 14 (11) ◽  
pp. 1207-1220 ◽  
Author(s):  
U. Lemmin ◽  
N. D'Adamo
Keyword(s):  
Cyclonic Circulation ◽  
Land Breeze ◽  
Lake Geneva ◽  
Spectral Peaks ◽  
Modifying Effect ◽  
Strong Winds ◽  
Diurnal Wind ◽  
Mean Circulation ◽  
Variable Wind ◽  
Land Breezes

Abstract. Records of wind, air temperature and air pressure from nine stations, situated along the shoreline of Lake Geneva, Switzerland, were analyzed for the summer period May to September. At all stations the consistent appearance of significant spectral peaks and changes in wind direction at the diurnal frequency indicates the importance of lake-land breezes. It is shown that the surrounding topography has a strong modifying effect (temporal and spatial) on the lake-land breeze. Superimposed on this cyclic wind pattern, short episodes of strong winds with long fetch over parts of Lake Geneva are regularly observed. Both of these winds exert a spatially variable wind stress over the lake surface on the same time scale. Typical examples of the expected lake's response are presented, among them the seasonally persistent gyre in the central part of the lake. Evidence is provided that this dominant circulation is part of a direct cyclonic circulation, generated by the curl of the diurnal wind field. It is concluded that the mean circulation is caused by these winds and affected by the topography of the surrounding land.

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