Heat island mitigation using water retentive pavement sprinkled with reclaimed wastewater

2008 ◽  
Vol 57 (5) ◽  
pp. 763-771 ◽  
Author(s):  
H. Yamagata ◽  
M. Nasu ◽  
M. Yoshizawa ◽  
A. Miyamoto ◽  
M. Minamiyama
Keyword(s):  
Heat Flux ◽  
Urban Areas ◽  
Sensible Heat Flux ◽  
Heat Island ◽  
Temperature Decrease ◽  
Sensible Heat ◽  
Reclaimed Wastewater ◽  
Wet Bulb Globe Temperature ◽  
The Road ◽  
Globe Temperature

In Japan, reclaimed wastewater has been recycled widely for non-potable urban applications and it is to be used for sprinkling roads to mitigate heat island in urban areas. To assess the heat island mitigation effects of the sprinkling reclaimed wastewater on water retentive pavement, we carried out a survey at Shiodome-District, Tokyo. The temperatures of air and roads, humidity, and WBGT (Wet-bulb globe temperature) were measured and heat flux was estimated to compare the condition of the areas with/without sprinkling. The following results were obtained. 1) Sprinkling reclaimed wastewater decreased the road surface temperature by 8 degrees during the daytime and by 3 degrees at night: temperatures equal to those on planting zones. Nevertheless sprinkling was done only in the daytime, the temperature decrease effect was not only obtained during the daytime: it continued through the night, due to the water retentive pavement. 2) Sprinkling reclaimed wastewater reduced the amount of sensible heat flux and increased that of latent heat flux. These results suggest that sprinkling reclaimed wastewater on water retentive pavement can effectively mitigate the heat island phenomenon.

Monitoring the Sensible Heat Flux over Urban Areas using Large Aperture Scintillometry: Case Study of Marseille City During the Escompte Experiment

2005 ◽  
Vol 118 (3) ◽  
pp. 449-476 ◽  
Author(s):  
J. -P. Lagouarde ◽  
M. Irvine ◽  
J. -M. Bonnefond ◽  
C. S. B. Grimmond ◽  
N. Long ◽  
...  
Keyword(s):  
Heat Flux ◽  
Urban Areas ◽  
Sensible Heat Flux ◽  
Sensible Heat ◽  
Large Aperture

Estimating urban sensible heat flux using satellite-based data

2021 ◽  
Author(s):  
Gabriel Rios ◽  
Prathap Ramamurthy
Keyword(s):  
Heat Flux ◽  
Land Cover ◽  
Model Validation ◽  
Satellite Data ◽  
Urban Areas ◽  
Sensible Heat Flux ◽  
Cost Effective ◽  
Surface Energy Budget ◽  
High Temporal Resolution ◽  
Sensible Heat

<p>A model for calculating sensible heat flux (Q<sub>H</sub>) – a primary component of the urban surface energy budget - is presented here. Remote sensing data from the NOAA GOES-16 satellite and a high-resolution land cover dataset are used as inputs to calculate the spatio-temporal variability in urban sensible heat flux. The primary motivation for this model is to present a cost-effective approach to calculate Q<sub>H</sub> independent of traditional flux observations and computational methods. The GOES-16 satellite data, which has a moderate spatial and high temporal resolution (2 km square at 5 minute intervals) enables the estimation of Q<sub>H</sub> over highly heterogeneous urban areas. The model is constructed using an iterative algorithm that uses surface layer turbulence parameterization to solve for Q<sub>H</sub> as a function of the enterprise GOES-16 Land Surface Temperature product, an urban air temperature model, publicly-accessible ground observations, and the National Land Cover Database (NLCD). Preliminary model validation was performed over a five-month period in 2019. Three (3) ground flux stations in the New York City metro area with varying degrees of urbanization were used for model validation. Statistics from validation found an RMSE of 42.9 W-m<sup>-</sup><sup>2</sup>, a mean bias of 12.9 W-m<sup>-2</sup>, and an R<sup>2</sup> of 0.80. Validation results demonstrate that the algorithm shows good correlation with observed values, suggesting that satellite data can be used as an accessible and cost-effective option to estimate Q<sub>H</sub> in urban areas.</p>

scholarly journals Numerical Evaluation of the Impact of Urbanization on Summertime Precipitation in Osaka, Japan

2015 ◽  
Vol 2015 ◽  
pp. 1-11 ◽  
Author(s):  
Hikari Shimadera ◽  
Akira Kondo ◽  
Kundan Lal Shrestha ◽  
Ken Kitaoka ◽  
Yoshio Inoue
Keyword(s):  
Land Use ◽  
Heat Flux ◽  
Urban Areas ◽  
Sensible Heat Flux ◽  
Wrf Model ◽  
Temporal Distribution ◽  
Urban Land Use ◽  
Sensible Heat ◽  
Impact Of Urbanization ◽  
The Impact

This study utilized the Weather Research and Forecasting (WRF) model version 3.5.1 to evaluate the impact of urbanization on summertime precipitation in Osaka, Japan. The evaluation was conducted by comparing the WRF simulations with the present land use and no-urban land use (replacing “Urban” with “Paddy”) for August from 2006 to 2010. The urbanization increased mean air temperature by 2.1°C in urban areas because of increased sensible heat flux and decreased mean humidity by 0.8 g kg−1because of decreased latent heat flux. In addition, the urbanization increased duration of the southwesterly sea breeze. The urbanization increased precipitation in urban areas and decreased in the surrounding areas. The mean precipitation in urban areas was increased by 20 mm month−1(27% of the total amount without the synoptic-scale precipitation). The precipitation increase was generally due to the enhancement of the formation and development of convective clouds by the increase in sensible heat flux during afternoon and evening time periods. The urbanization in Osaka changes spatial and temporal distribution patterns of precipitation and evaporation, and consequently it substantially affects the water cycle in and around the urban areas of Osaka.

scholarly journals Simulation of the Impacts of Urbanization on Winter Meteorological Fields over the Pearl River Delta Region

2017 ◽  
Vol 2017 ◽  
pp. 1-10 ◽  
Author(s):  
Naixing Luo ◽  
Liping Zeng ◽  
Wenshi Lin ◽  
Fangzhou Li ◽  
Baolin Jiang ◽  
...  
Keyword(s):  
Heat Flux ◽  
Latent Heat ◽  
Urban Areas ◽  
Pearl River Delta ◽  
Sensible Heat Flux ◽  
Heat Fluxes ◽  
Pearl River ◽  
Sensible Heat ◽  
Pearl River Delta Region ◽  
Delta Region

The influences of urbanization on weather in Guangdong Province, China, were studied using the Weather Research and Forecasting model from 31 December 2009 through 3 January 2010. Model outputs were compared with extensive monitoring of meteorological data to examine the simulation ability. Model results between tests (with and without land-use change) show that the urbanization had major effects on meteorological fields across nearly the entire Pearl River Delta region and particularly in urban areas. Studied fields (wind speed, temperature, precipitation, and sensible and latent heat fluxes) were affected by the urbanization of the PRD region. The major influences occurred in urban areas, where wind speeds decreased greatly, while the daytime surface upward sensible heat flux clearly increased. Unlike the sensible heat flux, the latent heat flux had a nonmonotonic increase or decrease. As a consequence of the two heat fluxes, 2-m temperature varied with location and time. Change of precipitation was complex. The main rain band became more concentrated, while precipitation decreased upwind of the urban area and increased downwind.

scholarly journals On the Derivation of Material Thermal Properties Representative of Heterogeneous Urban Neighborhoods

2009 ◽  
Vol 48 (8) ◽  
pp. 1725-1732 ◽  
Author(s):  
F. Salamanca ◽  
E. S. Krayenhoff ◽  
A. Martilli
Keyword(s):  
Heat Flux ◽  
Thermal Properties ◽  
Urban Areas ◽  
Sensible Heat Flux ◽  
Thermal Response ◽  
Urban Canopy ◽  
Grid Cell ◽  
Atmospheric Model ◽  
Heat Fluxes ◽  
Sensible Heat

Abstract An important question arises when modeling a heterogeneous landscape (e.g., an urbanized area) with a mesoscale atmospheric model. The surface within a grid cell of the model (which has a typical dimension of one or more kilometers) can be composed of patches of surfaces of different character. The total sensible heat flux in the grid cell, then, is the aggregate of the heat fluxes from each individual surface, each one with a unique thermal response arising from its thermal properties, among other factors. Current methods to estimate the sensible heat flux consider only one (in the case of flat terrain) or three (roof, walls, and ground, for urban areas) active surfaces with thermal properties that are ideally representative of the materials present in the grid cell. The question is then how to choose the representative thermal properties such that the heat flux computed by the model most closely approximates the aggregate of the fluxes from the different patches. In this work a new way to average building material thermal properties for urban canopy parameterizations is presented, and a suite of idealized numerical simulations demonstrates its superiority to two more standard averages. Moreover, this novel approach points to a new way of determining physical properties that are representative of heterogeneous zones.

scholarly journals Study on Surface Heat Budget of Various Pavements for Urban Heat Island Mitigation

2012 ◽  
Vol 2012 ◽  
pp. 1-11 ◽  
Author(s):  
Hideki Takebayashi ◽  
Masakazu Moriyama
Keyword(s):  
Heat Flux ◽  
Urban Heat Island ◽  
Heat Budget ◽  
Sensible Heat Flux ◽  
Weather Conditions ◽  
Surface Heat ◽  
Heat Island ◽  
Sensible Heat ◽  
Urban Heat ◽  
Surface Heat Budget

The surface heat budgets of various pavement surfaces are studied with the aim of mitigating the urban heat island effect. In this study, the thermal characteristics of pavements are examined using data from observations. The net radiation, surface temperature, temperature under the surface, conduction heat flux, and core weight for each experimental surface are recorded, together with the weather conditions at the time of observation. The latent heat flux is estimated from the observed weight of the cores. The surface heat budget under the same weather conditions is examined, and the sensible heat flux from each target surface is calculated. The parameters that influence the surface heat budget, for example, solar reflectance (albedo), evaporative efficiency, heat conductivity, and heat capacity, are examined. On a typical summer day, the maximum reduction in the sensible heat flux from that on a normal asphalt surface is about 150 W/m2for an asphalt surface with water-retaining material and about 100 W/m2for a cement concrete surface with water-retaining material, depending on the albedo of each surface.

scholarly journals Response of the Energy Balance on the Margin of the Greenland Ice Sheet to Temperature Changes

1990 ◽  
Vol 36 (123) ◽  
pp. 217-221 ◽  
Author(s):  
Roger J. Braithwaite ◽  
Ole B. Olesen
Keyword(s):  
Heat Flux ◽  
Energy Balance ◽  
Air Temperature ◽  
Sensible Heat Flux ◽  
Ice Sheet ◽  
Temperature Response ◽  
Greenland Ice Sheet ◽  
Energy Balance Model ◽  
Balance Model ◽  
Sensible Heat

AbstractDaily ice ablation on two outlet glaciers from the Greenland ice sheet, Nordbogletscher (1979–83) and Qamanârssûp sermia (1980–86), is related to air temperature by a linear regression equation. Analysis of this ablation-temperature equation with the help of a simple energy-balance model shows that sensible-heat flux has the greatest temperature response and accounts for about one-half of the temperature response of ablation. Net radiation accounts for about one-quarter of the temperature response of ablation, and latent-heat flux and errors account for the remainder. The temperature response of sensible-heat flux at QQamanârssûp sermia is greater than at Nordbogletscher mainly due to higher average wind speeds. The association of high winds with high temperatures during Föhn events further increases sensible-heat flux. The energy-balance model shows that ablation from a snow surface is only about half that from an ice surface at the same air temperature.

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