scholarly journals URBAN MICROCLIMATE IMPROVEMENT USING ENVI-MET CLIMATE MODEL

2018 ◽  
Vol XLII-4 ◽  
pp. 69-76 ◽  
Author(s):  
E. Chatzinikolaou ◽  
C. Chalkias ◽  
E. Dimopoulou
Keyword(s):  
Thermal Comfort ◽  
Urban Environment ◽  
Climate Model ◽  
Dimensional Space ◽  
Three Dimensional ◽  
Urban Morphology ◽  
Urban Microclimate ◽  
3D Space ◽  
Roadside Vegetation ◽  
Urban Heat

<p><strong>Abstract.</strong> The aim of this paper is the modelling of urban microclimate, based on the limits imposed by the complexity of the three-dimensional space of cities. To this purpose, different Bioclimatic Scenarios were investigated through the microclimatic simulations using the micro-scale numerical model, ENVI-met 4v, applied in a case study of a Block in a highly residential neighbourhood of Athens. The study compares the bioclimatic scenarios of the roof top and road side vegetation plan in the current conditions, in order to evaluate how the existence of vegetation can affect the local air temperature and the thermal comfort condition of urban environment. This study also highlights the need to manage those microclimate data, through a geodatabase and provides a GIS approach of data organization and visualization. Creating building facades of the distributed temperature has showed that urban morphology parameters have an obvious impact on temperature distribution in the 3D space. On the other hand, the proposed roadside vegetation scenario has proved to be the most suitable way to improve the thermal comfort conditions of urban environment, as it can eliminate the Urban Heat Island (UHI) effects.</p>

scholarly journals Analysis of Urban Greening Scenarios for Improving Outdoor Thermal Comfort in Neighbourhoods of Lecce (Southern Italy)

Climate ◽  
2021 ◽  
Vol 9 (7) ◽  
pp. 116
Author(s):  
Elisa Gatto ◽  
Fabio Ippolito ◽  
Gennaro Rispoli ◽  
Oliver Savio Carlo ◽  
Jose Luis Santiago ◽  
...  
Keyword(s):  
Thermal Comfort ◽  
Urban Environment ◽  
Southern Italy ◽  
Hot Spot ◽  
Outdoor Thermal Comfort ◽  
Urban Greening ◽  
Urban Microclimate ◽  
Field Campaigns ◽  
Typical Summer ◽  
Radiant Temperature

This study analyses the interactions and impacts between multiple factors i.e., urban greening, building layout, and meteorological conditions that characterise the urban microclimate and thermal comfort in the urban environment. The focus was on two neighbourhoods of Lecce city (southern Italy) characterised through field campaigns and modelling simulations on a typical hot summer day. Field campaigns were performed to collect greening, building geometry, and microclimate data, which were employed in numerical simulations of several greening scenarios using the Computational Fluid Dynamics-based and microclimate model ENVI-met. Results show that, on a typical summer day, trees may lead to an average daily decrease of air temperature by up to 1.00 °C and an improvement of thermal comfort in terms of Mean Radiant Temperature (MRT) by up to 5.53 °C and Predicted Mean Vote (PMV) by up to 0.53. This decrease is more evident when the urban greening (in terms of green surfaces and trees) is increased by 1266 m2 in the first neighbourhood and 1988 m2 in the second one, with respect to the current scenario, proving that shading effect mainly contributes to improving the urban microclimate during daytime. On the contrary, the trapping effect of heat, stored by the surfaces during the day and released during the evening, induces an increase of the spatially averaged MRT by up to 2 °C during the evenings and a slight deterioration of thermal comfort, but only locally where the concentration of high LAD trees is higher. This study contributes to a better understanding of the ecosystem services provided by greening with regard to microclimate and thermal comfort within an urban environment for several hours of the day. It adds knowledge about the role of green areas in a Mediterranean city, an important hot spot of climate change, and thus it can be a guide for important urban regeneration plans.

scholarly journals Integrating Urban Building Space and Transportation Space to Solve Traffic Congestion

2014 ◽  
Vol 3 (1) ◽  
pp. 7 ◽  
Author(s):  
Hong Zhang
Keyword(s):  
Urban Space ◽  
Traffic Congestion ◽  
Dimensional Space ◽  
Three Dimensional ◽  
Urban Morphology ◽  
Multidimensional Space ◽  
Urban Sustainable Development ◽  
Urban Function ◽  
Space Separation ◽  
Three Dimensional Space

<p>Today, with urban function system increasingly complicated, there exist problems which are seriously hindering urban sustainable development in most cities such as traffic jams, constructive destruction, building space separation with traffic space, poor urban space resource utilization and so on. So the article makes a number of integration methods of urban building space and transportation space from the perspective of urban morphology integration. It tries to integrate urban environment with techniques of multidimensional space interludes, cascading, infiltration between building space and traffic space in three-dimensional space coordinates, to achieve the objectives   of proper division, solving traffic congestion problems and the establishment of a new dynamic three-dimensional transport system.</p>

scholarly journals Integrating Urban Building Space and Transportation Space to Solve Traffic Congestion

2014 ◽  
Vol 3 ◽  
pp. 7
Author(s):  
Hong Zhang
Keyword(s):  
Urban Space ◽  
Traffic Congestion ◽  
Dimensional Space ◽  
Three Dimensional ◽  
Urban Morphology ◽  
Multidimensional Space ◽  
Urban Sustainable Development ◽  
Urban Function ◽  
Space Separation ◽  
Three Dimensional Space

<p>Today, with urban function system increasingly complicated, there exist problems which are seriously hindering urban sustainable development in most cities such as traffic jams, constructive destruction, building space separation with traffic space, poor urban space resource utilization and so on. So the article makes a number of integration methods of urban building space and transportation space from the perspective of urban morphology integration. It tries to integrate urban environment with techniques of multidimensional space interludes, cascading, infiltration between building space and traffic space in three-dimensional space coordinates, to achieve the objectives   of proper division, solving traffic congestion problems and the establishment of a new dynamic three-dimensional transport system.</p>

scholarly journals Study of urban microclimate conditions in a commercial area of an urban centre and the environmental regeneration potential

2021 ◽  
Vol 899 (1) ◽  
pp. 012017
Author(s):  
Th Rapti ◽  
A Kantzioura
Keyword(s):  
Geographical Location ◽  
Urban Morphology ◽  
Specific Humidity ◽  
Urban Centre ◽  
Urban Microclimate ◽  
The Road ◽  
Urban Geometry ◽  
Commercial Area ◽  
Urban Heat ◽  
Air Speed

Abstract Urban heat island (UHI) is a phenomenon that affects the urban microclimate. Land use, urban geometry, cover materials, vegetation, the water element and human activities are the most important factors that affect the UHI. This research focused on the study and analysis of the urban microclimate of three sections of a commercial street area that differ in their morphology. The first area includes a stream near the road, the second area includes the purely commercial part of the street and the third area includes the fringes of a hill in (Thessaloniki, “Toumpa”, Gr Lampraki Street). Using the Envimet V4 program, three simulations were performed for the selected study areas for the hottest day of the previous year, August 1, 2020. The values with the largest variations in all three areas were those of relative and specific humidity and finally air speed. The air temperature was higher in relation to the suburban area (UHI) and did not show significant differences in the three study areas. This leads us to the conclusion that the urban morphology, orientation and geographical location of the three study areas played the most important role in shaping the urban microclimate. Finally, is suggested one alternative scenario for optimizing the microclimate in the most burdened area of the three.

Minimization of Common-Mode Voltage of Three-Phase Five-Level NPC Inverter Using 3D Space Vector Modulation

2020 ◽  
Vol 29 (14) ◽  
pp. 2050229 ◽  
Author(s):  
Palanisamy Ramasamy ◽  
Vijayakumar Krishnasamy
Keyword(s):  
Dimensional Space ◽  
Three Dimensional ◽  
Harmonic Distortion ◽  
Space Vector Modulation ◽  
Space Vector ◽  
Common Mode ◽  
Common Mode Voltage ◽  
3D Space ◽  
Vector Modulation ◽  
Switching State

In this paper, a three-dimensional Space Vector Modulation (3D SVM) is implemented for minimization of Common-Mode Voltage (CMV) of five-level Neutral Point Clamped (NPC) inverter. The 3D SVM control includes all merits of 2D SVM and provides better control compared to other PWM strategies. The switching state vectors are selected based on the nearest vector Switching State Vector (NSV); it selects the switching vectors which are having the minimum CMV level. It leads to minimization of the bearing voltage and protection of the drive from the damage; also this system reduces the total harmonic distortion. The switching time is calculated by reference vector identification with large and small subcubes tracking and prisms tracking in 3D cubic region. The CMV level with 3D SVM scheme is compared with other PWM methods. The simulation and hardware results are verified using Matlab Simulink and FPGA processor.

Development, validation, and demonstration of the VTUF-3D v1.0 urban micro-climate model to support assessments of urban vegetation influences on human thermal comfort

2018 ◽  
Author(s):  
Kerry Nice
Keyword(s):  
Thermal Comfort ◽  
Urban Environment ◽  
Urban Areas ◽  
Climate Model ◽  
Canopy Cover ◽  
Individual Tree ◽  
New Model ◽  
Human Thermal Comfort ◽  
Physiological Processes ◽  
The Impact

With urban areas facing future longer duration heat-waves and temperature extremes from climate change and growing urban development, adaptation strategies are needed. Examining the role that increased tree cover and water availability can have on human thermal comfort (HTC) in urban areas as part of these strategies has been done using observations, but further work requires a modelling tool suited for this task. Sufficient model resolution is needed to resolve variables used to calculate HTC, as well as the ability to model the physiological processes of vegetation and their interaction with water and with the rest of the urban environment. The lack of such a model has been identified as a research gap in the urban climate area and has impaired the ability to fully examine the use of urban greenery and water for improved human thermal comfort. A new model, VTUF-3D (Vegetated Temperatures Of Urban Facets), addresses this gap by embedding the functionality of the MAESPA tree process model (Duursma &amp; Medlyn 2012), that can model individual trees, vegetation, and soil components, within the TUF-3D (Krayenhoff &amp; Voogt 2007) urban micro-climate model. An innovative tiling approach, allows the new model to account for important vegetative physiological processes and shading effects using configurable templates to allow representation of any type of vegetation or water sensitive design feature. The high resolution of VTUF-3D is sufficient to examine the processes that drive human thermal comfort (HTC). This allows detailed calculations of surface temperatures, mean radiant temperature (Tmrt), and a HTC index, the universal thermal climate index (UTCI), across an urban canyon. An extensive validation process, using three different observation data sets to validate a number of different and key aspects of the VTUF-3D model, has shown it performs well and is suitable for use to examine critical questions relating to the role of vegetation and water in the urban environment. A demonstration of the model using modelling scenarios of varying canopy cover shows that average peak daytime HTC improvements of 1◦C UTCI (and 2.3◦C UTCI) are possible in doubling (and quadrupling) existing street cover canopies, with localised effects under canopy cover approaching 5◦C UTCI. These scenarios also show the value of the existing canopy cover, as reductions and elimination of existing cover can create reductions in HTC of 2◦C UTCI. In addition, reductions in average air temperature (Ta) across urban canyons can differ by 1◦C between streets with differing canopy cover. After the development, validation, and demonstration of this new model, it is now possible to conduct further analysis to quantify the impact each individual tree can have on temperatures in urban canyons. Further, the model can help inform the optimal arrangement and quantity of trees to maximise temperature moderation effects and be used to generate best practices guidelines for urban greening.

Path-Tracking Control of Stochastic Quadrotor Aircraft in Three-Dimensional Space

2015 ◽  
Vol 137 (10) ◽  
Author(s):  
K. D. Do
Keyword(s):  
Tracking Control ◽  
Dimensional Space ◽  
Three Dimensional ◽  
Path Tracking ◽  
Effective Control ◽  
Practical Implementation ◽  
Unit Quaternion ◽  
3D Space ◽  
Quadrotor Aircraft ◽  
Deterministic Components

Despite the fact that environmental loads (forces and moments) induced by wind on quadrotor vertical take-off and landing (VTOL) aircraft consist of both deterministic and stochastic components, all existing works on controlling the aircraft either ignore these loads or treat them as deterministic. This ignorance or treatment deteriorates the control performance in a practical implementation. This paper presents a constructive design of controllers for a quadrotor aircraft to track a reference path in three-dimensional (3D) space under both deterministic and stochastic disturbances. A combination of Euler angles and unit-quaternion for the attitude representation of the aircraft is used to result in an effective control design, and to achieve path-tracking control results. Weak and strong nonlinear Lyapunov functions are introduced to overcome difficulties caused by underactuation and Hessian terms induced by stochastic differentiation rule. To overcome the inherent underactuation of the aircraft, the roll and pitch angles of the aircraft are considered as immediate controls. Potential projection functions are introduced to design estimates of the deterministic components and covariances of the stochastic components. Simulations illustrate the results.

Targeted urban heat mitigation strategies using urban morphology databases and micro-climate modelling to examine the urban heat profile

2020 ◽  
Author(s):  
Kerry Nice ◽  
Ashley Broadbent
Keyword(s):  
Thermal Comfort ◽  
Urban Morphology ◽  
Mitigation Strategies ◽  
Local Context ◽  
Climate Modelling ◽  
Local Conditions ◽  
Local Climate ◽  
Human Thermal Comfort ◽  
Local Climate Zones ◽  
Urban Heat

&lt;p&gt;Strategies for urban heat mitigation often make broad and non-specific recommendations (i.e. plant more trees) without accounting for local context. As a result, resources might be allocated to areas of lesser need over those where more urgent interventions are needed. Also, these interventions might return less than optimal results if local conditions are not considered. This project aims to assist with these interventions by providing a method to examine the urban heat profile of a city through an automated systematic approach. Using urban morphology information from databases such as WUDAPT, areas of cities are clustered into representative local climate zones (LCZs) and modelled at a micro-scale using localised features and properties. This bottom up modelling approach, using the VTUF-3D, UMEP, and TARGET models, allows these areas to be assessed in detail for their human thermal comfort performance and provide a city-wide heat map of thermal comfort. It also allows mitigation scenarios to be tested and targeted for each cluster type. A case study performed using this method for Melbourne is presented.&lt;/p&gt;

scholarly journals Multi-model comparison of urban heat island modelling approaches

2018 ◽  
Vol 18 (14) ◽  
pp. 10655-10674 ◽  
Author(s):  
Jan Karlický ◽  
Peter Huszár ◽  
Tomáš Halenka ◽  
Michal Belda ◽  
Michal Žák ◽  
...  
Keyword(s):  
Wind Speed ◽  
Urban Heat Island ◽  
Urban Environment ◽  
Model Comparison ◽  
Climate Model ◽  
Heat Island ◽  
Significant Difference ◽  
Urban Heat ◽  
Urban Parameterizations ◽  
The Impact

Abstract. Cities are characterized by different physical properties of surface compared to their rural counterparts, resulting in a specific regime of the meteorological phenomenon. Our study aims to evaluate the impact of typical urban surfaces on the central European urban climate in several model simulations, performed with the Weather Research and Forecasting (WRF) model and Regional Climate Model (RegCM). The specific processes occurring in the typical urban environment are described in the models by various types of urban parameterizations, greatly differing in complexity. Our results show that all models and urban parameterizations are able to reproduce the most typical urban effect, the summer evening and nocturnal urban heat island, with the average magnitude of 2–3 °C. The impact of cities on the wind is clearly dependent on the urban parameterization employed, with more simple ones unable to fully capture the wind speed reduction induced by the city. In the summer, a significant difference in the boundary-layer height (about 25 %) between models is detected. The urban-induced changes of temperature and wind speed are propagated into higher altitudes up to 2 km, with a decreasing tendency of their magnitudes. With the exception of the daytime in the summer, the urban environment improves the weather conditions a little with regard to the pollutant dispersion, which could lead to the partly decreased concentration of the primary pollutants.

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