Temperature Distribution of Walls and Ground Surface in Street Canyon

Vu, Thanh Ca; Asaeda, Takashi; Shibahara, Chihiro; Fujino, Takeshi; Nakamura, Kouichi; Murakami, Masahirô

doi:10.2208/prohe.38.413

Cited by 4 publications

(2 citation statements)

References 2 publications

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“…A compromise between credibility and simplicity is found in the mesoscale models with bulk parameterization schemes [ Johnson et al , 1990; Oke et al , 1991; Mills , 1993; Mills and Arnfield , 1993; Vu et al , 1994]. In these models, profile shapes for the mean variables are assumed inside the urban canopy that can be shifted according to an average background value within this layer.…”

Section: Introductionmentioning

confidence: 99%

Development and evaluation of an urban parameterization scheme in the Penn State/NCAR Mesoscale Model (MM5)

et al. 2005

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[1] In the present study, the Penn State/NCAR Mesoscale Model (MM5) was modified by considering recent advances in the urban boundary layer. In particular, the modifications were carried out in two directions: (1) With respect to the thermal properties of an urban surface the surface energy balance was modified by taking into account the anthropogenic heat released in urban areas and the urban heat storage term to account for urban/building mass effects, including hysteresis; and (2) the surface stress and fluxes of heat and momentum were modified following recent advances in the atmospheric boundary layer over rough surfaces under unstable conditions. The whole process was supplemented by detailed information on land use cover, derived from satellite image analysis. The modifications were applied to the high-resolution nonlocal medium-range forecast planetary boundary layer parameterization scheme, based on work by Troen and Mahrt (1986). The improvements seen with the modified model, after comparison with available measurements of temperature and fluxes, refer to (1) the strengthening of the nocturnal urban heat island; (2) the changes in the temperature, which proved to be favorable through the whole diurnal cycle, resulting in decreasing the temperature amplitude wave; (3) the decrease of turbulence and fluxes during the daytime; and (4) the diffusion coefficient and potential temperature profiles that are reduced during daytime and are increased at the lower levels during the night and thus affect accordingly the mixing height.

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Section: Introductionmentioning

confidence: 99%

Development and evaluation of an urban parameterization scheme in the Penn State/NCAR Mesoscale Model (MM5)

et al. 2005

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“…Η ενσωµάτωση απλών µονοδιάστατων (bulk) παραµετρικών σχηµάτων, που υπολογίζουν το επιφανειακό ενεργειακό ισοζύγιο, σε µοντέλα µέσης κλίµακας καθιστά ευκολότερη την προσοµοίωση των αστικών περιοχών, τον υπολογισµό της ΑΘΝ και των τοπικών ροών που αναπτύσσονται στο ΑΣΑΟΣ (Souch and Grimmond, 2006). Τα σχήµατα αυτά αποτελούν έναν καλό συνδυασµό αξιοπιστίας και µικρών υπολογιστικών απαιτήσεων (Johnson et al, 1990;Oke et al, 1991;Mills, 1993;Mills and Arnfield, 1993;Vu et al, 1994), όπου τα προφίλ των µέσων µεταβλητών µέσα στον ΑΘ µεταβάλλονται συναρτήσει µιας µέσης τιµής υποβάθρου στο στρώµα προσοµοίωσης.…”

Section: μονοδιάστατα παραµετρικά σχήµαταunclassified

Παραμετροποίηση Ροών Ορμής Και Θερμότητας Για Αστικές Περιοχές Σε Προγνωστικά Μετεωρολογικά Μοντέλα

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Urbanization leads to the replacement of natural surfaces with buildings and paved surfaces. This change in surface characteristics together with human activities in urban environments alters heat, moisture and momentum exchange processes in the atmospheric boundary layer and distinguishes the urban climate from that of surrounding rural areas. In the last few years, several efforts have been made in order to improve the representation of urban surface characteristics in mesoscale models, either to the ‘dynamical’ part (impact on the wind field and the turbulent kinetic energy) or to the ‘thermal’ part (impact on the heat fluxes). Shadowing and radiative trapping effects are also considered. In the present study, modifications both to the ‘thermal’ and ‘dynamical’ part were incorporated in the meteorological PSU/NCAR Mesoscale Model (MM5). With respect to the ‘thermal’ part, the sensible heat storage flux is taken into account as a sink/source term in the thermodynamic equation at the surface layer. Shadowing effects are also considered as a function of the heat storage flux. The anthropogenic heat flux is introduced as a source term in the thermodynamic equation at the surface layer, based on the diurnal spatial distribution of the emission inventory. With respect to the ‘dynamical’ part, the surface stress and fluxes of heat and momentum under unstable conditions, as well as the diffusion coefficients under stable conditions, were modified, following recent advances over rough surfaces. The whole process was supplemented by detailed information on land use cover, derived from high resolution satellite image analysis. The model results were compared with sonic anemometer measurements of turbulence, tethered balloon soundings and routine meteorological data in Attica peninsula. The improvements, seen with the modified model, refer to the: (i) decrease of turbulence and fluxes during daytime (ii) decrease of the temperature amplitude wave (iii) strengthening of the nocturnal urban heat island (iv) the reduction/increase of the diffusion coefficient and potential temperature profiles during daytime/nighttime respectively (v) reasonable frictional retard in the sea-breeze front during daytime and the increase of the wind speed during nighttime (vi) estimation of the mixing height through the diffusion coefficients profile, while the differences in the calculated atmospheric boundary-layers depths are due to the lack of a unique definition application.

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A k - *epsiv Turbulence Closure Model For The Atmospheric Boundary Layer Including Urban Canopy

Ashie

Asaeda

2002

Boundary-Layer Meteorology

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Temperature Distribution of Walls and Ground Surface in Street Canyon

Cited by 4 publications

References 2 publications

Development and evaluation of an urban parameterization scheme in the Penn State/NCAR Mesoscale Model (MM5)

Development and evaluation of an urban parameterization scheme in the Penn State/NCAR Mesoscale Model (MM5)

Παραμετροποίηση Ροών Ορμής Και Θερμότητας Για Αστικές Περιοχές Σε Προγνωστικά Μετεωρολογικά Μοντέλα

A k - *epsiv Turbulence Closure Model For The Atmospheric Boundary Layer Including Urban Canopy

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