scholarly journals Effects of Urban Configuration on Human Thermal Conditions in a Typical Tropical African Coastal City

2013 ◽  
Vol 2013 ◽  
pp. 1-12 ◽  
Author(s):  
Emmanuel Lubango Ndetto ◽  
Andreas Matzarakis
Keyword(s):  
Thermal Comfort ◽  
Climate Model ◽  
Meteorological Data ◽  
Urban Climate ◽  
Thermal Conditions ◽  
Urban Street ◽  
Coastal City ◽  
Human Thermal Conditions ◽  
Comfort Parameters

A long-term simulation of urban climate was done using the easily available long-term meteorological data from a nearby synoptic station in a tropical coastal city of Dar es Salaam, Tanzania. The study aimed at determining the effects of buildings’ height and street orientations on human thermal conditions at pedestrian level. The urban configuration was represented by a typical urban street and a small urban park near the seaside. The simulations were conducted in the microscale applied climate model of RayMan, and results were interpreted in terms of the thermal comfort parameters of mean radiant (Tmrt) and physiologically equivalent (PET) temperatures. PET values, high as 34°C, are observed to prevail during the afternoons especially in the east-west oriented streets, and buildings’ height of 5 m has less effect on the thermal comfort. The optimal reduction ofTmrtand PET values for pedestrians was observed on the nearly north-south reoriented streets and with increased buildings’ height especially close to 100 m. Likewise, buildings close to the park enhance comfort conditions in the park through additional shadow. The study provides design implications and management of open spaces like urban parks in cities for the sake of improving thermal comfort conditions for pedestrians.

Modeling the Thermal Comfort of Internal Building Spaces in Hospital

2014 ◽  
Vol 584-586 ◽  
pp. 753-756 ◽  
Author(s):  
Andrey Volkov ◽  
Artem Sedov ◽  
Pavel Chelyshkov ◽  
Ekaterina Kulikova
Keyword(s):  
Thermal Comfort ◽  
Indoor Environment ◽  
Critical Factor ◽  
Thermal Conditions ◽  
Strong Relationship ◽  
Indoor Environmental Quality ◽  
Operational Conditions ◽  
Hospital Patients ◽  
Materials Used ◽  
Comfort Parameters

<p class="p0">Creating a comfortable indoor environment has been one of the mainconcerns when it comes to the design and operation of buildings. Buildings are a crucial part of our daily life, on average people spends 85 % of their time performing activities inside of buildings and therefore the quality of the indoor environment is a critical factor affecting the happiness and productivity of building users.The indoor environmental quality has a strong relationship on the thermal conditions of a space which is directly affected by the amount of heat lost or gained due to the properties of the materials used, the external environmental conditions and the inner sources of heat; In consequence, efforts have to be made to maintain proper thermal conditions by means of using natural and mechanical strategies to provide heating, cooling and ventilation. While the thermal comfort is an important aspect for the average user of a building, it becomes a critical aspect when it comes to population highly sensitive to thermal conditions. Children under and patients in hospitals with low levels of immune system are more likely to feel discomfort under certain operational conditions of ventilation, cooling and heating delivery systems.Particularly in this study have been investigated the thermal comfort and thermal comfort parameters for children, toddlers and hospital patients in three locations during the typical operation of systems in late spring.</p>

scholarly journals The thermal response of small and shallow lakes to climate change: new insights from 3D hindcast modelling

2021 ◽  
Vol 12 (2) ◽  
pp. 439-456
Author(s):  
Francesco Piccioni ◽  
Céline Casenave ◽  
Bruno Jacques Lemaire ◽  
Patrick Le Moigne ◽  
Philippe Dubois ◽  
...  
Keyword(s):  
Climate Change ◽  
Water Temperature ◽  
Shallow Lakes ◽  
Thermal Regime ◽  
Meteorological Data ◽  
Thermal Response ◽  
Thermal Conditions ◽  
3D Analysis ◽  
Sharp Separation

Abstract. Small, shallow lakes represent the majority of inland freshwater bodies. However, the effects of climate change on such ecosystems have rarely been quantitatively addressed. We propose a methodology to evaluate the thermal response of small, shallow lakes to long-term changes in the meteorological conditions through model simulations. To do so, a 3D thermal-hydrodynamic model is forced with meteorological data and used to hindcast the evolution of an urban lake in the Paris region between 1960 and 2017. Its thermal response is assessed through a series of indices describing its thermal regime in terms of water temperature, thermal stratification, and potential cyanobacteria production. These indices and the meteorological forcing are first analysed over time to test the presence of long-term monotonic trends. 3D simulations are then exploited to highlight the presence of spatial heterogeneity. The analyses show that climate change has strongly impacted the thermal regime of the study site. Its response is highly correlated with three meteorological variables: air temperature, solar radiation, and wind speed. Mean annual water temperature shows a considerable warming trend of 0.6 ∘C per decade, accompanied by longer stratification and by an increase in thermal energy favourable to cyanobacteria proliferation. The strengthening of thermal conditions favourable for cyanobacteria is particularly strong during spring and summer, while stratification increases especially during spring and autumn. The 3D analysis allows us to detect a sharp separation between deeper and shallower portions of the basin in terms of stratification dynamics and potential cyanobacteria production. This induces highly dynamic patterns in space and time within the study site that are particularly favourable to cyanobacteria growth and bloom initiation.

Seasonal effects of urban street shading on long-term outdoor thermal comfort

2011 ◽  
Vol 46 (4) ◽  
pp. 863-870 ◽  
Author(s):  
Ruey-Lung Hwang ◽  
Tzu-Ping Lin ◽  
Andreas Matzarakis
Keyword(s):  
Thermal Comfort ◽  
Outdoor Thermal Comfort ◽  
Seasonal Effects ◽  
Urban Street

Shading Effect on Outdoor Thermal Comfort in High-Density City a Case Based Study of Beijing

2014 ◽  
Vol 1065-1069 ◽  
pp. 2927-2930 ◽  
Author(s):  
Bai Chuan Ma ◽  
Qi Sang ◽  
Ji Feng Gou
Keyword(s):  
Thermal Comfort ◽  
Field Experiments ◽  
Meteorological Data ◽  
Thermal Conditions ◽  
Central Business District ◽  
Outdoor Thermal Comfort ◽  
View Factor ◽  
Thermal Environments ◽  
Sky View Factor ◽  
Business District

Shading provided by buildings affects outdoor thermal environments and, therefore, influences the long-term thermal comfort of people in outdoor spaces. This study conducted several field experiments to analyze the outdoor thermal conditions on urban streets in central business district (CBD) of Beijing. The RayMan model was utilized for calculating Sky view factor (SVF) and outdoor thermal comfort using meteorological data of one year period. Analytical results indicate that slightly shaded areas (SVF > 0.5) typically have highly frequent hot conditions during summer, particularly at noon; however, highly shaded locations (SVF < 0.3) generally reduce the intra-urban air temperature in winter; moderately shaded areas (0.3 < SVF < 0.5) show the advantage for balancing the hot conditions in summer and cold conditions in winter throughout whole year. Sky view factor can be used as a comprehensive and practical urban planning index at local scale, i.e. urban canyon street and residential estate. It provides a novelty method on scientific planning and sustainable development of city.

Long-term evaluation of residential summer thermal comfort: Measured vs. perceived thermal conditions in nZEB houses in Wallonia

2021 ◽  
Vol 190 ◽  
pp. 107531
Author(s):  
Olivier Dartevelle ◽  
Geoffrey van Moeseke ◽  
Erwin Mlecnik ◽  
Sergio Altomonte
Keyword(s):  
Thermal Comfort ◽  
Thermal Conditions ◽  
Term Evaluation

scholarly journals Verification of ECMWF System 4 for seasonal hydrological forecasting in a northern climate

2017 ◽  
Vol 21 (11) ◽  
pp. 5747-5762 ◽  
Author(s):  
Rachel Bazile ◽  
Marie-Amélie Boucher ◽  
Luc Perreault ◽  
Robert Leconte
Keyword(s):  
Bias Correction ◽  
Climate Models ◽  
Climate Model ◽  
Initial Conditions ◽  
Meteorological Data ◽  
Lead Times ◽  
Seasonal Forecasts ◽  
Hydrological Forecasting ◽  
Northern Climate

Abstract. Hydropower production requires optimal dam and reservoir management to prevent flooding damage and avoid operation losses. In a northern climate, where spring freshet constitutes the main inflow volume, seasonal forecasts can help to establish a yearly strategy. Long-term hydrological forecasts often rely on past observations of streamflow or meteorological data. Another alternative is to use ensemble meteorological forecasts produced by climate models. In this paper, those produced by the ECMWF (European Centre for Medium-Range Forecast) System 4 are examined and bias is characterized. Bias correction, through the linear scaling method, improves the performance of the raw ensemble meteorological forecasts in terms of continuous ranked probability score (CRPS). Then, three seasonal ensemble hydrological forecasting systems are compared: (1) the climatology of simulated streamflow, (2) the ensemble hydrological forecasts based on climatology (ESP) and (3) the hydrological forecasts based on bias-corrected ensemble meteorological forecasts from System 4 (corr-DSP). Simulated streamflow computed using observed meteorological data is used as benchmark. Accounting for initial conditions is valuable even for long-term forecasts. ESP and corr-DSP both outperform the climatology of simulated streamflow for lead times from 1 to 5 months depending on the season and watershed. Integrating information about future meteorological conditions also improves monthly volume forecasts. For the 1-month lead time, a gain exists for almost all watersheds during winter, summer and fall. However, volume forecasts performance for spring varies from one watershed to another. For most of them, the performance is close to the performance of ESP. For longer lead times, the CRPS skill score is mostly in favour of ESP, even if for many watersheds, ESP and corr-DSP have comparable skill. Corr-DSP appears quite reliable but, in some cases, under-dispersion or bias is observed. A more complex bias-correction method should be further investigated to remedy this weakness and take more advantage of the ensemble forecasts produced by the climate model. Overall, in this study, bias-corrected ensemble meteorological forecasts appear to be an interesting source of information for hydrological forecasting for lead times up to 1 month. They could also complement ESP for longer lead times.

scholarly journals Modelling Long-Term Urban Temperatures with Less Training Data: A Comparative Study Using Neural Networks in the City of Madrid

2021 ◽  
Vol 13 (15) ◽  
pp. 8143
Author(s):  
Miguel Núñez-Peiró ◽  
Anna Mavrogianni ◽  
Phil Symonds ◽  
Carmen Sánchez-Guevara Sánchez ◽  
F. Javier Neila González
Keyword(s):  
Neural Networks ◽  
Meteorological Data ◽  
Urban Climate ◽  
Data Availability ◽  
Training Data ◽  
Training Dataset ◽  
Urban Context ◽  
Model Reliability ◽  
The City

In the last decades, urban climate researchers have highlighted the need for a reliable provision of meteorological data in the local urban context. Several efforts have been made in this direction using Artificial Neural Networks (ANN), demonstrating that they are an accurate alternative to numerical approaches when modelling large time series. However, existing approaches are varied, and it is unclear how much data are needed to train them. This study explores whether the need for training data can be reduced without overly compromising model accuracy, and if model reliability can be increased by selecting the UHI intensity as the main model output instead of air temperature. These two approaches were compared using a common ANN configuration and under different data availability scenarios. Results show that reducing the training dataset from 12 to 9 or even 6 months would still produce reliable results, particularly if the UHI intensity is used. The latter proved to be more effective than the temperature approach under most training scenarios, with an average RMSE improvement of 16.4% when using only 3 months of data. These findings have important implications for urban climate research as they can potentially reduce the duration and cost of field measurement campaigns.

scholarly journals Long-term dynamics of urban thermal comfort in China’s four major capital cities across different climate zones

PeerJ ◽  
2019 ◽  
Vol 7 ◽  
pp. e8026 ◽  
Author(s):  
Yao Fu ◽  
Zhibin Ren ◽  
Qiuyan Yu ◽  
Xingyuan He ◽  
Lu Xiao ◽  
...  
Keyword(s):  
Thermal Comfort ◽  
Thermal Environment ◽  
Meteorological Data ◽  
Economic Activities ◽  
Physiological Equivalent Temperature ◽  
Rapid Urbanization ◽  
Climate Zones ◽  
Chinese Cities ◽  
Northern Cities

China has experienced intensive urbanization over the past decades. However, it is still unclear about the influence of urbanization on urban thermal comfort and how the effect varies with climate condition. Based on long-term daily meteorological data from 1990 to 2015 in four Chinese cities undergoing rapid urbanization, our study tried to detect the long-term dynamics of summer urban thermal comfort across different climate zones and analyze their relationships with urbanization. Our results showed that urbanization can increase urban temperature and decrease relative humidity and wind velocity. Urban thermal comfort and discomfort days also changed greatly, especially in Harbin, Northeast China from 1990 to 2015. However, such changes for different cities across different climate zones are inconsistent. Results also showed that urbanization especially for social economic activities can have a significant influence on the physiological Equivalent Temperature (PET). Compared with southern cities, the PET in northern cities such as Harbin and Changchun in this study is more sensitive to urbanization. These results reveal that the changing patterns of urban thermal comfort in Chinese cities under rapid urbanization, and help government take some effective measures to improve urban thermal environment.

DROUGHT OCCURRENCE UNDER LITHUANIAN CLIMATIC CONDITIONS

2015 ◽  
Author(s):  
Laima TAPARAUSKIENĖ ◽  
Veronika LUKŠEVIČIŪTĖ
Keyword(s):  
Meteorological Data ◽  
Standardized Precipitation Index ◽  
Vegetation Period ◽  
Climatic Conditions ◽  
Precipitation Record ◽  
Calculation Step ◽  
Drought Conditions ◽  
The Standardized Precipitation Index ◽  
June July

This study provides the analysis of drought conditions of vegetation period in 1982-2014 year in two Lithuanian regions: Kaunas and Telšiai. To identify drought conditions the Standardized Precipitation Index (SPI) was applied. SPI was calculated using the long-term precipitation record of 1982–2014 with in-situ meteorological data. Calculation step of SPI was taken 1 month considering only vegetation period (May, June, July, August, September). The purpose of investigation was to evaluate the humidity/aridity of vegetation period and find out the probability of droughts occurrence under Lithuanian climatic conditions. It was found out that according SPI results droughts occurred in 14.5 % of all months in Kaunas region and in 15.8 % in Telšiai region. Wet periods in Kaunas region occurred in 15.8 %, and in Telšiai region occurrence of wet periods was – 18.8 % from all evaluated months. According SPI evaluation near normal were 69.7 % of total months during period of investigation in Kaunas and respectively – 65.5 % in Telšiai. The probability for extremely dry period under Lithuania climatic conditions are pretty low – 3.0 % in middle Lithuania and 2.4 % in western part of Lithuania.

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