## 日本ヒートアイランド学会論文集 Vol.5 (2010)

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10A001学術論文

**東京で観測された局地豪雨の実態調査: 2002年8月2日および2004年8月10日の事例の比較解析**

Examining Local Heavy Rainfalls Observed in Tokyo: Case Study of August 2 2002 and August 10 2004

概要を開く

The present study describes essential features of the local weather when heavy rainfalls occur in the Tokyo metropolitan area. Case study was carried out in detail for the two heavy rainfall events: August 2 2002 (Case 1) and August 10 2004 (Case 2). The following characteristics are found. (a) The atmospheric stability was low while Japan Island was covered with Pacific high for both cases. (b) In the Case 1, the E-S type wind system was observed and surface winds from the Kashima bay, Tokyo bay, and Sagami bay converged in Tokyo during the several hours before heavy rainfalls occurred. (c) Additionally, it was found that the cold outflows enhanced the convergence. (d) On the other hand, such a convergence was not found in the Case 2, which causes the convective rainfalls quickly decreased.

10A002学術論文

**都市散水効果の定量評価に向けた大気・地下連成‐水・熱環境モデルの開発**

Development of an Atmosphere-Subsurface-Coupled, Hydrothermal Environment Model for Quantitative Evaluation of the Effect of Urban Water Sprinkling

概要を開く

For quantitative evaluation of the effect of water sprinkling as a mitigating method of urban “Heat Island”, a comprehensive numerical model is proposed. The developed model describes both air-water-vapor movement and heat transport in atmosphere and subsurface, by using the generalized concept of multi-phase, multi-component solid-fluid system. It includes hydrodynamic phenomena, such as pseudo static air flow in atmospheric boundary layer, the heat balance of solar radiation and long-wave radiation, evaporation, transient heat transfer among the solid, liquid and gas phases. In order to confirm the performance of the model, several case studies have been made regarding the basic modeled processes. The calculated results are reasonable and consistent with the analytical solutions and/or laboratory experiment with the reasonable parameters.

10A003学術論文

**大気・地下連成‐水・熱環境モデルを用いた屋外散水実験の再現性の検討**

Reproducibility of the Atmosphere-Subsurface-Coupled Hydrothermal Environment Model for the Field Experiment of Water Sprinkling

概要を開く

By applying the Atmosphere-Surface-Coupled, Hydrothermal Environment Model, the reproducibility of the field experiment of water sprinkling is examined.

Firstly, making a 2-D vertical model which includes atmosphere and subsurface regions, and inputting the meteorological data (atmosphere temperature, wind velocity, relative humidity and solar radiation) of the experimental site, the hydrothermal parameters of the model are identified by matching the calculated with the observed surface and subsurface temperatures at un-sprinkled condition. Then, giving water volume on the surface layer of the model at water sprinkling, the changes of environment near water sprinkled area are simulated. As the results, the atmosphere, surface and subsurface temperatures observed from daytime to the following morning are preferably reproduced by the model.

Firstly, making a 2-D vertical model which includes atmosphere and subsurface regions, and inputting the meteorological data (atmosphere temperature, wind velocity, relative humidity and solar radiation) of the experimental site, the hydrothermal parameters of the model are identified by matching the calculated with the observed surface and subsurface temperatures at un-sprinkled condition. Then, giving water volume on the surface layer of the model at water sprinkling, the changes of environment near water sprinkled area are simulated. As the results, the atmosphere, surface and subsurface temperatures observed from daytime to the following morning are preferably reproduced by the model.

10B001技術報告

**豊橋市内の中規模緑地におけるクールアイランド現象の 調査と周辺市街地に対する冷却効果**

Cool island phenomena and cooling effect of green area in Toyohashi City on the surrounding area

概要を開く

Simultaneous observation of air temperatures was carried out inside and outside of the city park (Takashi Ryokuchi) in the central area of the Toyohashi city to estimate “cool island intensity” defined as temperature difference between the park and residential areas, and evaluate the effect of cold air advection or drainage from the city park. Observation period is Jul. 30 to Aug. 30 and the number of observation points was 29. Observation results show that the averaged cool island intensity was -0.84°C during the observation period. The cooling effect of Takashi Ryokuchi on the surroundings (residential area) in calm condition was small compared with that in windy condition.

10A004学術論文

**ヒートアイランド現象を抑制する多孔質保水煉瓦の基礎的特性**

Basic Characteristics of Water Permeable/Retainable Porous Paving Bricks

for Controlling Urban Heat Island Phenomenon

概要を開く

The aim of this paper is the design of water permeable/retainable porous paving bricks for controlling the urban heat island phenomenon. The model porous bricks, which had 22-43% open porosity and 0.4-50μm of average pore size, were prepared by sintering using cubic-shape fly-ash powders with very narrow particle size distributions. Influence of pore sizes and porosities in the model bricks on water pump-up ability, coefficient of permeability, water vapor evaporation ability and evaporation cooling effect of the brick surface temperature were evaluated quantitatively. The brick which had 33% or more of porosity and 4-30μm of average pore size was considered to be the most suitable for water permeable/retainable porous paving bricks.

10A005学術論文

**Large-Eddy Simulation のフィルター操作に基づく都市キャノピーモデルのスカラー輸送方程式の導出**

Derivation of Scalar Transport Equation of Urban Canopy Model Based on Filtering Operation of Large-Eddy Simulation

概要を開く

We propose a new approach to derive a spatially-averaged transport equation for a scalar quantity, such as
temperature or concentration, for an urban canopy model. First, in order to mathematically describe the actual
momentum field as a completely continuous field, the underling concepts of the immersed boundary method are
employed, where we assume that (i) the entire simulation space is filled with a fluid, and (ii) an external body force
field exists that reduces the wind speed to zero at all positions coinciding with the space occupied by the buildings.
Second, we mathematically describe the field of a scalar quantity as a completely continuous field by introducing a
source/sink field that acts only inside the space occupied by the buildings and controls the values of the scalar
quantity at the acting points. Then, we obtain a spatially-averaged scalar transport equation by applying a
(solid-inclusive) spatial averaging operation to the governing equation for the scalar field. Finally, by assuming that
the source/sink field controls the spatial-average of the scalar quantity inside the buildings to be equal to that
outside the buildings, we can obtain a spatially-averaged scalar transport equation that has no undefined term in the
case the boundary of the averaging cell does not cross the space occupied by buildings.