scholarly journals Spatiotemporal Characteristics of Lake Breezes over Lake Taihu, China

2017 ◽  
Vol 56 (7) ◽  
pp. 2053-2065 ◽  
Author(s):  
Yongwei Wang ◽  
Yaqi Gao ◽  
Hairun Qin ◽  
Jianping Huang ◽  
Cheng Liu ◽  
...  
Keyword(s):  
Weather Forecasting ◽  
Late Onset ◽  
Lake Taihu ◽  
Eastern China ◽  
Yangtze River Delta ◽  
Urban Heat Islands ◽  
Occurrence Frequency ◽  
Urban Heat ◽  
Lake Breezes ◽  
The Impact

AbstractLake Taihu is a shallow lake located in the Yangtze River delta region in eastern China. Lake breezes and their interactions with urban heat islands are of great importance to air quality and weather forecasting. In this study, surface observations at a dense network and Wind Profile Radar measurements were utilized to characterize the lake breezes at Lake Taihu and assess the impact of geophysical factors on the development and intensity of the lake breezes. The lake breezes were characterized by a low occurrence frequency of 12%–17% (defined as the percentage of days with lake breezes in a given month), weak speed (annual mean ranging from 1.5 to 3.3 m s−1), late onset [average onset around 1110 local standard time (LST), with a range of 0900–1300 LST], short duration (annual mean 3.5 h), and low circulation depth (average depth of 400 m from 1200 to 1400 LST). The lake breezes were greatly suppressed when the geostrophic winds were higher than 4.1 m s−1. The low heat capacity of shallow water (mean depth 2.0 m) led to small temperature differences between the land and the lake, which was the main factor responsible for the low occurrence frequency along Lake Taihu. All of the characteristic parameters showed distinct seasonal variations. Increased frequencies, earlier onset times, and longer durations on the northern lakeshore were indicative of the impact of the urban heat island on the lake breezes.

scholarly journals Green roofs and cool materials as retrofitting strategies for urban heat island mitigation: Case study in Belgrade, Serbia

2018 ◽  
Vol 22 (6 Part A) ◽  
pp. 2309-2324
Author(s):  
Marija Lalosevic ◽  
Mirko Komatina ◽  
Marko Milos ◽  
Nedzad Rudonja
Keyword(s):  
Green Roofs ◽  
Urban Heat Islands ◽  
Temperature Changes ◽  
Heat Islands ◽  
Air Temperatures ◽  
Urban Heat ◽  
Microclimatic Conditions ◽  
Typical Summer ◽  
Planning And Construction ◽  
The Impact

The effect of extensive and intensive green roofs on improving outdoor microclimate parameters of urban built environments is currently a worldwide focus of research. Due to the lack of reliable data for Belgrade, the impact of extensive and intensive green roof systems on mitigating the effects of urban heat islands and improving microclimatic conditions by utilizing high albedo materials in public spaces were studied. Research was conducted on four chosen urban units within existing residential blocks in the city that were representative of typical urban planning and construction within the Belgrade metropolitan area. Five different models (baseline model and four potential models of retrofitting) were designed, for which the temperature changes at pedestrian and roof levels at 07:00, 13:00, 19:00 h, on a typical summer day, and at 01:00 h, the following night in Belgrade were investigated. The ENVI-met software was used to model the simulations. The results of numerical modeling showed that utilizing green roofs in the Belgrade climatic area could reduce air temperatures in the surroundings up to 0.47, 1.51, 1.60, 1.80 ?C at pedestrian level and up to 0.53, 1.45, 0.90, 1.45 ?C at roof level for four potential retrofitting strategies, respectively.

Comparison of surface and canopy urban heat islands within megacities of eastern China

2019 ◽  
Vol 156 ◽  
pp. 160-168 ◽  
Author(s):  
Yonghong Hu ◽  
Meiting Hou ◽  
Gensuo Jia ◽  
Chunlei Zhao ◽  
Xiaoju Zhen ◽  
...  
Keyword(s):  
Eastern China ◽  
Urban Heat Islands ◽  
Heat Islands ◽  
Urban Heat

scholarly journals Development of an operational modelling system for urban heat islands: an application to Athens, Greece

2013 ◽  
Vol 1 (5) ◽  
pp. 4963-4996
Author(s):  
T. M. Giannaros ◽  
D. Melas ◽  
I. A. Daglis ◽  
I. Keramitsoglou
Keyword(s):  
Weather Forecasting ◽  
Weather Prediction ◽  
Urban Climate ◽  
Mitigation Strategies ◽  
Urban Heat Islands ◽  
Heat Island ◽  
Meteorological Model ◽  
Near Surface ◽  
Urban Heat ◽  
Modelling System

Abstract. The urban heat island (UHI) effect is one prominent form of localized anthropogenic climate modification. It represents a significant urban climate problem since it occurs in that layer of the atmosphere where almost all daily human activities take place. This paper presents the development of a high-resolution modelling system that could be used for simulating the UHI effect in the context of operational weather forecasting activities. The modelling system is built around a state-of-the-art numerical weather prediction model, properly modified to allow for the better representation of the urban climate. The model performance in terms of simulating the near-surface air temperature and thermal comfort conditions over the complex urban area of Athens, Greece, is evaluated during a 1.5-month operational implementation in the summer of 2010. Results from this case study reveal an overall satisfactory performance of the modelling system. The discussion of the results highlights the important role that, given the necessary modifications, a meteorological model can play as a supporting tool for developing successful heat island mitigation strategies. This is further underlined through the operational character of the presented modelling system.

scholarly journals Spatial modelling of urban heat islands and its planning implications in Obio/Akpor local government area

2021 ◽  
Vol 5 (5) ◽  
pp. 240-250
Author(s):  
Lawson Nwidum ◽  
Kurotamuno Peace Jackson ◽  
Ibama Brown
Keyword(s):  
Local Government ◽  
Surface Temperature ◽  
Local Government Area ◽  
Urban Heat Islands ◽  
Tree Planting ◽  
Urban Surface ◽  
Spectral Radiance ◽  
Electric Cars ◽  
Urban Heat ◽  
The Impact

Urban Heat Island (UHI) has become a global recurring phenomenon in most urban centres. Obio/Akpor Local Government Area has had a fair share of this phenomenon owing to its thriving trend in both planned and unplanned urbanisations. The study looks at the impact of UHI in selected communities in Obio/Akpor Local Government in five epochs of 2000, 2005, 2010, 2015 and 2020. Parts of the objectives include identifying the UHI in these communities in the Local Government Area, modelling of UHI in selected communities in Obio/Akpor Local Government Area and determining the trend in UHI using Epoch data of Urban Surface Temperature from LANDSAT thermal imageries Figure 1. The study adopted Thermal Infrared Remote (TIR) Sensing and Geospatial Information System (GIS) Techniques using LANDSAT TM, LANDSAT ETM and LANDSAT OLI sensors to acquire Urban Surface temperature data emitted by objects in the study area and store the information as a digital number (DN) thermal band (B6, B61 and B10) as well as secondary data acquired from the Nigerian Meteorological Agency (NIMET). Urban Surface Temperature was obtained through the following processes: Acquisition of Urban Surface Temperature value of the study area in form of DN, the conversion of DN to Spectral radiance using the Spectral radiance equation. The data were processed, analysed, and modelled using ESRI’s ArcGIS 10.1. The results revealed that in 2000, the Average Urban Temperature of the study area was 23.480°C, the value increase to 27.647°C in 2005 with a difference of 4.167°C. The temperature of 2005 increased to 31.598°C in 2010 with a difference in temperature of 3.951°C. Accordingly, the temperature of 2010 increased to 33.054°C in 2015 with a temperature difference of 1.456°C and temperature of 2015 increased to 33.070°C with a difference of 0.016°C. The analysis shows an increasing trend of 40% in the Urban Surface Temperature in the study area in the various years under investigation. The study recommends that development should be extended to other Local Government Areas in the state to reduce rural-urban migration to Obio/Akpor Local Government. Tree planting should be encouraged as a way of mitigating the effect of air pollution, heatwaves and harmful gases emitted into the environment by combust engines and gas flaring, the use of combustion engines be replaced by electric cars to reduce the level of carbon dioxide (CO2) emitted ti environment. Policymakers to restrict unplanned urban growth and to increase tree planting in the built-up areas.

Synergistic Interactions between Urban Heat Islands and Heat Waves: The Impact in Cities Is Larger than the Sum of Its Parts

2013 ◽  
Vol 52 (9) ◽  
pp. 2051-2064 ◽  
Author(s):  
Dan Li ◽  
Elie Bou-Zeid
Keyword(s):  
Urban Heat Island ◽  
Rural Areas ◽  
Urban Areas ◽  
Heat Waves ◽  
Mitigation Strategies ◽  
Urban Heat Islands ◽  
Heat Island ◽  
Heat Islands ◽  
Urban Heat ◽  
The Impact

AbstractCities are well known to be hotter than the rural areas that surround them; this phenomenon is called the urban heat island. Heat waves are excessively hot periods during which the air temperatures of both urban and rural areas increase significantly. However, whether urban and rural temperatures respond in the same way to heat waves remains a critical unanswered question. In this study, a combination of observational and modeling analyses indicates synergies between urban heat islands and heat waves. That is, not only do heat waves increase the ambient temperatures, but they also intensify the difference between urban and rural temperatures. As a result, the added heat stress in cities will be even higher than the sum of the background urban heat island effect and the heat wave effect. Results presented here also attribute this added impact of heat waves on urban areas to the lack of surface moisture in urban areas and the low wind speed associated with heat waves. Given that heat waves are projected to become more frequent and that urban populations are substantially increasing, these findings underline the serious heat-related health risks facing urban residents in the twenty-first century. Adaptation and mitigation strategies will require joint efforts to reinvent the city, allowing for more green spaces and lesser disruption of the natural water cycle.

scholarly journals Understanding the Impact of Urbanization on Surface Urban Heat Islands—A Longitudinal Analysis of the Oasis Effect in Subtropical Desert Cities

2017 ◽  
Vol 9 (7) ◽  
pp. 672 ◽  
Author(s):  
Chao Fan ◽  
Soe Myint ◽  
Shai Kaplan ◽  
Ariane Middel ◽  
Baojuan Zheng ◽  
...  
Keyword(s):  
Longitudinal Analysis ◽  
Urban Heat Islands ◽  
Heat Islands ◽  
Urban Heat ◽  
Impact Of Urbanization ◽  
The Impact ◽  
Oasis Effect

scholarly journals Comparative Analysis of Urban Heat Island Intensities in Chinese, Russian, and DPRK Regions across the Transnational Urban Agglomeration of the Tumen River in Northeast Asia

2018 ◽  
Vol 10 (8) ◽  
pp. 2637 ◽  
Author(s):  
Bing Li ◽  
Zhifeng Liu ◽  
Ying Nan ◽  
Shengnan Li ◽  
Yanmin Yang
Keyword(s):  
Urban Heat Island ◽  
Urban Agglomeration ◽  
Urban Heat Islands ◽  
City Size ◽  
Vegetation Coverage ◽  
Heat Island ◽  
Tumen River ◽  
Heat Islands ◽  
Urban Heat ◽  
The Impact

Quantification of the spatial pattern of urban heat island intensities across the transnational urban agglomeration of the Tumen River is important for the promotion of sustainable regional development. This study employed Landsat images and MODIS LST data obtained in 2016 to determine the intensity of urban heat islands in this region, enabling direct comparison of data from the sub-regions of China, Democratic People’s Republic of Korea (DPRK), and Russia. The average urban heat island intensity for the region was found to be 1.0 °C, with the highest intensity of 3.0 °C occurring during the summer time. The intensity of urban heat islands on the Chinese side was higher than on the other two sides, with city size, socio-economic development levels and vegetation coverage significantly affect their intensity. Urban heat island effects in Chinese cities in the region contribute increases in maximum summer temperatures and the number of high-temperature days that pose a threat to the health of their residents. The factors that influence urban heat island intensities in these cities and the impacts of urban heat island effects on the quality of life and health of residents are discussed. Therefore, it is desirable to reduce the impact of urban heat island effects on cities in the region by increasing the area of green spaces they contain, as well as controlling their size and population.

scholarly journals Characterization of the urban microclimate by the modelling of urban planning policies in France

2021 ◽  
Vol 2042 (1) ◽  
pp. 012065
Author(s):  
Magalie Técher ◽  
Hassan Ait Haddou ◽  
Rahim Aguejdad
Keyword(s):  
Urban Planning ◽  
Urban Heat Island ◽  
Urban Form ◽  
Urban Heat Islands ◽  
Heat Island ◽  
Urban Microclimate ◽  
Heat Islands ◽  
Urban Heat ◽  
The Impact ◽  
Planning Policies

Abstract With the increase of Urban Heat Islands (UHI) and the effects of global warming, cities will face challenges in anticipating these phenomena. However, the complexity of urban development within the framework of urban planning policies, makes difficult for urban decision-makers to anticipate the Urban Heat Islands within their territory. In this paper, we propose a methodology to assess the impact of urban planning policies on Urban Heat Island. Thanks to a coupling of 2D urban growth model, 3D constructability model and urban microclimate simulation, this tool will make it possible to visualize the impact of urban planning decisions on urban form and on Urban Heat Island.

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