scholarly journals Coupling a Single-Layer Urban Canopy Model with a Simple Atmospheric Model: Impact on Urban Heat Island Simulation for an Idealized Case

2004 ◽  
Vol 82 (1) ◽  
pp. 67-80 ◽  
Author(s):  
Hiroyuki KUSAKA ◽  
Fujio KIMURA
Keyword(s):  
Urban Heat Island ◽  
Single Layer ◽  
Urban Canopy ◽  
Atmospheric Model ◽  
Heat Island ◽  
Urban Canopy Model ◽  
Urban Heat ◽  
Canopy Model

A New Modeling Approach to Forecast Building Energy Demands During Extreme Heat Events in Complex Cities

2011 ◽  
Author(s):  
Estatio Gutie´rrez ◽  
Jorge E. Gonza´lez ◽  
Robert Bornstein ◽  
Mark Arend ◽  
Alberto Martilli
Keyword(s):  
Urban Heat Island ◽  
Heat Wave ◽  
Extreme Event ◽  
Large City ◽  
Urban Canopy ◽  
Anthropogenic Heat ◽  
Heat Island ◽  
Urban Canopy Model ◽  
Urban Heat ◽  
Canopy Model

The thermal response of a large city including the energy production aspects of it are explored for a large and complex city using urbanized atmospheric mesoscale modeling. The Weather Research and Forecasting (WRF) mesocale model is coupled to a multi-layer urban canopy model that considers thermal and mechanical effects of the urban environment including a building scale energy model to account for anthropogenic heat contributions due to indoor-outdoor temperature differences. This new urban parameterization is used to evaluate the evolution and the resulting urban heat island formation associated to a 3-day heat wave in New York City (NYC) during the summer of 2010. High resolution (250 m.) urban canopy parameters (UCPs) from the National Urban Database were employed to initialize the multi-layer urban parameterization. The precision of the numerical simulations is evaluated using a range of observations. Data from a dense network of surface weather stations, wind profilers and Lidar measurements are compared to model outputs over Manhattan and its surroundings during the 3-days event. The thermal and drag effects of buildings represented in the multilayer urban canopy model improves simulations over urban regions giving better estimates of the surface temperature and wind speed. An accurate representation of the nocturnal urban heat island registered over NYC in the event was obtained from the improved model. The accuracy of the simulation is further assessed against more simplified urban parameterizations models with positive results with new approach. Results are further used to quantify the energy consumption of the buildings during the heat wave, and to explore alternatives to mitigate the intensity of the UHI during the extreme event.

A New Modeling Approach to Forecast Building Energy Demands During Extreme Heat Events in Complex Cities

2013 ◽  
Vol 135 (4) ◽  
Author(s):  
Estatio Gutiérrez ◽  
Jorge E. González ◽  
Robert Bornstein ◽  
Mark Arend ◽  
Alberto Martilli
Keyword(s):  
Urban Heat Island ◽  
Heat Wave ◽  
Extreme Event ◽  
Surface Air Temperature ◽  
Urban Canopy ◽  
Anthropogenic Heat ◽  
Heat Island ◽  
Urban Canopy Model ◽  
Urban Heat ◽  
Canopy Model

The thermal response of a large and complex city including the energy production aspects of it are explored using urbanized atmospheric mesoscale modeling. The Weather Research and Forecasting (WRF) Mesocale model is coupled to a multilayer urban canopy model that considers thermal and mechanical effects of the urban environment including a building scale energy model to account for anthropogenic heat contributions due to indoor–outdoor temperature differences. This new urban parameterization is used to evaluate the evolution and the resulting urban heat island (UHI) formation associated to a 3-day heat wave in New York City (NYC) during the summer of 2010. High-resolution (250 m) urban canopy parameters (UCPs) from the National Urban Database were employed to initialize the multilayer urban parameterization. The precision of the numerical simulations is evaluated using a range of observations. Data from a dense network of surface weather stations, wind profilers, and Lidar measurements are compared to model outputs over Manhattan and its surroundings during the 3-days event. The thermal and drag effects of buildings represented in the multilayer urban canopy model improves simulations over urban regions giving better estimates of the 2 m surface air temperature and 10 m wind speed. An accurate representation of the nocturnal urban heat island registered over NYC in the event was obtained from the improved model. The accuracy of the simulation is further assessed against more simplified urban parameterizations models with positive results with new approach. Results are further used to quantify the energy consumption of the buildings during the heat wave, and to explore alternatives to mitigate the intensity of the UHI during the extreme event.

scholarly journals Sensitivity analysis and optimization of a mesoscale atmospheric model

2018 ◽  
Author(s):  
Χρήστος Γιάνναρος
Keyword(s):  
Sensitivity Analysis ◽  
Single Layer ◽  
Urban Canopy ◽  
Atmospheric Model ◽  
Weather Research And Forecasting ◽  
Urban Canopy Model ◽  
Mesoscale Atmospheric Model ◽  
Canopy Model ◽  
Weather Research

Η παρούσα διδακτορική διατριβή επικεντρώνεται στη αριθμητική προσομοίωση ακραίων θερμικών συνθηκών σε περιφερειακή και αστική κλίμακα. Ειδικότερα, ένα σύγχρονο μετεωρολογικό μοντέλο μέσης κλίμακας, το Weather Research and Forecasting (WRF), χρησιμοποιήθηκε με σκοπό την ανάλυση και βελτιστοποίηση της αποδοτικότητάς του στην προσομοίωση επεισοδίων καύσωνα και του φαινομένου της Αστικής Θερμικής Νησίδας (ΑΘΝ). Διάφορα πειράματα ευαισθησίας πραγματοποιήθηκαν κατά τη διάρκεια μιας σειράς τριών αριθμητικών μελετών. H πρώτη αριθμητική μελέτη έδειξε ότι η προσομοίωση καυσώνων στην μέση κλίμακα εξαρτάται σημαντικά από την α) παραμετροποίηση των συντελεστών επιφανειακής ανταλλαγής θερμότητας στα σχήματα παραμετροποίησης του στρώματος επιφάνειας, β) την προσομοίωση των ροών θερμότητας από τα μοντέλα επιφάνειας της γης, και γ) την παραμετροποίηση της κατακόρυφης ανάμειξης στα σχήματα παραμετροποίησης του ατμοσφαιρικού οριακού στρώματος. Τα αποτελέσματα της δεύτερης αριθμητικής μελέτης έδειξαν ότι η ακριβής και λεπτομερής αναπαράσταση των χρήσεων γης στα αστικά περιβάλλοντα είναι απαραίτητη για την αποτύπωση του φαινομένου της ΑΘΝ. Τέλος, η τρίτη αριθμητική μελέτη ανέδειξε τη σημασία των πολύπλοκων φυσικών διεργασιών που λαμβάνουν χώρα στις πόλεις και επηρεάζουν καταλυτικά την ενδο-αστική κατανομή των θερμοκρασιών. Για την σωστή αναπαράσταση αυτών των διεργασιών είναι η απαραίτητη η σύζευξη του μοντέλου WRF με το μοντέλο αστικού θόλου Single Layer Urban Canopy Model (SLUCM), χρησιμοποιώντας μια τροποποιημένη εξίσωση για τον υπολογισμό της θερμοκρασίας του αστικού εδάφους. Εξίσου απαραίτητη είναι η προσαρμογή των παραμέτρων επιφάνειας και αστική γεωμετρίας στην εκάστοτε περιοχή ενδιαφέροντος έτσι ώστε να επιτυγχάνεται η ρεαλιστική αναπαράσταση του αστικού περιβάλλοντος. Στο πλαίσιο αυτό, η ανάλυση ευαισθησίας που πραγματοποιήθηκε έδειξε ότι η δημιουργία και εξέλιξη της ΑΘΝ επηρεάζονται καθοριστικά από την ανακλαστικότητα των επιφανειών, την γεωμετρία των αστικών χαράδρων και το ποσοστό αστικής κάλυψης. Η εφαρμογή των βέλτιστων παραμέτρων για την Αθήνα οδήγησε στην σημαντική βελτίωση της απόδοσης του μοντέλου, με τις μειώσεις των θερμοκρασιακών αποκλίσεων να κυμαίνονται από 0.30 έως περίπου 1.60 βαθμούς κελσίου. Το γεγονός ότι οι παράμετροι που χρησιμοποιήθηκαν είναι σύμφωνες με τα πραγματικά χαρακτηριστικά της πόλης παρέχει την βεβαιότητα ότι το μοντέλο WRF έχει βελτιστοποιηθεί κάτω από την συγκεκριμένη διαμόρφωση και μπορεί να χρησιμοποιηθεί για την μελέτη και πρόγνωση της ΑΘΝ στην Αθήνα υπό τις συνθήκες ενός θερμότερου κλίματος στο μέλλον.

scholarly journals Explore the Accuracy of the Pedestrian Level Temperature Estimated by the Combination of LCZ with WRF Urban Canopy Model through the Microclimate Measurement Network

2021 ◽  
Vol 8 (1) ◽  
pp. 14
Author(s):  
Yu-Cheng Chen ◽  
Fang-Yi Cheng ◽  
Cheng-Pei Yang ◽  
Tzu-Ping Lin
Keyword(s):  
Heat Capacity ◽  
Urban Development ◽  
Urban Climate ◽  
Urban Canopy ◽  
Subtropical Climate ◽  
Heat Island ◽  
Urban Canopy Model ◽  
Urban Heat ◽  
The City ◽  
Canopy Model

Due to the urban heat island effect becoming more evident in the cities in Taiwan, the urban climate has become an essential factor in urban development. Taiwan is located on the border of tropical and subtropical climate zones, the climate condition is hot and humid, and the city shows high-density development. The dense urban development has increased the heat storage capacity of the ground and buildings. However, if only the climate stations set by the Central Meteorological Bureau to observe the climate data are applied, the predicted results differ from the actual urban climate conditions due to the small number of these stations and the too far distance between them. Therefore, this study employs the local climate zone (LCZ), which can classify the land features by considering both land use and land cover, and can be freely generated from satellite images. The LCZ classification method can view the type of the city through the height and density of obstacles. This study also combines the urban canopy model (UCM) of the mesoscale climate prediction model and weather research and forecasts (WRF). This approach can calculate vertical and horizontal planes of the city, such as building volume, road width, the influence of streets and roofs, roof heat capacity, building wall heat capacity, etc., to predict the climatic conditions in different lands in the study area. Simultaneously, to understand the actual distribution of urban climate more accurately, this study used the microclimate measurement network built in the research area to produce pedestrian-level temperature distribution and compared the estimated results with the actual measured values for urban climate assessment. This study can understand the cause of urban heat islands and assist urban planners more appropriately formulate heat island mitigation strategies in different regions.

scholarly journals Quantitative Analysis of Factors Contributing to Urban Heat Island Intensity

2012 ◽  
Vol 51 (5) ◽  
pp. 842-854 ◽  
Author(s):  
Young-Hee Ryu ◽  
Jong-Jin Baik
Keyword(s):  
Urban Heat Island ◽  
Single Layer ◽  
Anthropogenic Heat ◽  
Heat Island ◽  
Impervious Surfaces ◽  
Additional Heat ◽  
Urban Geometry ◽  
Causative Factors ◽  
Urban Heat ◽  
Vertical Walls

AbstractThis study identifies causative factors of the urban heat island (UHI) and quantifies their relative contributions to the daytime and nighttime UHI intensities using a mesoscale atmospheric model that includes a single-layer urban canopy model. A midlatitude city and summertime conditions are considered. Three main causative factors are identified: anthropogenic heat, impervious surfaces, and three-dimensional (3D) urban geometry. Furthermore, the 3D urban geometry factor is subdivided into three subfactors: additional heat stored in vertical walls, radiation trapping, and wind speed reduction. To separate the contributions of the factors and interactions between the factors, a factor separation analysis is performed. In the daytime, the impervious surfaces contribute most to the UHI intensity. The anthropogenic heat contributes positively to the UHI intensity, whereas the 3D urban geometry contributes negatively. In the nighttime, the anthropogenic heat itself contributes most to the UHI intensity, although it interacts strongly with other factors. The factor that contributes the second most is the impervious-surfaces factor. The 3D urban geometry contributes positively to the nighttime UHI intensity. Among the 3D urban geometry subfactors, the additional heat stored in vertical walls contributes most to both the daytime and nighttime UHI intensities. Extensive sensitivity experiments to anthropogenic heat intensity and urban surface parameters show that the relative importance and ranking order of the contributions are similar to those in the control experiment.

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