東京都心部ビル屋上の気象観測に基づく熱環境の評価  [in Japanese] Thermal Environment of Building Roofs Based on Measurements in the Central Areas of Tokyo  [in Japanese]

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Abstract

都市の熱環境とエネルギー消費構造の相互関係を解明し,改善の道を探るための統合数値モデルの開発・検証に有用なデータを得るため,東京都心のビル街の屋上で気象要素を測定した.超高層ビル街と近辺の大規模緑地縁辺部における1996年夏の観測では,ビル街の気温と緑地縁辺の裸地上の気温の対照的な変動が典型的にとらえられた.また,比較的均質な中高層ビル街で1998~99年に行った年間継続測定から,屋上面熱収支を主要項別に見積もることができた.四季の典型的な快晴日各1日における比較によれば,ビル表面の加熱による顕熱放出や壁体の蓄熱による午後から夜間にかけての再放熱は夏に格別大きいわけではなく,むしろ春の方が大きかった.熱収支残差として求めた表面の顕熱フラックスと,高さ2.5mにおいて渦相関法で求めた顕熱フラックスとは,風速・乱流測定に理想的とは言えない屋上空間にもかかわらず,昼間の変動パターン・大きさとも基本的によく一致した.上向きの顕熱フラックスと(表面温-気温)の比αは,通常観測された風の範囲内(概略6ms^-1以下)では風速の一次関数となり,この関係を上記の数値モデルに用いて顕熱フラックスを見積もることの合理性について確証が得られた.

In order to obtain validation data for a model system describing the relationship between urban energy system and thermal environment, meteorological properties were measured on the roof of buildings in the central areas of Tokyo. From a series of measurement in the skyscrapers quarter and its neighborhood, typical contrast was found in air temperature variations in the building canopy layer and above a bare soil corner of a garden. From another series of measurement performed in the old city for more than one year, four major factors of heat budget were evaluated for the roof surface of a building of 24 stories --- net short-wave and long-wave radiations, total turbulent sensible and latent heat fluxes, and heat conduction through the wall. Comparison of these factors on four cloudless days selected from different seasons, when the latent heat flux could be neglected, indicated that the heat transfer from the surface to the ambient air was rather larger in April than in August. General coincidence was found between the sensible heat flux (H) evaluated for the surface as the residual term and that measured by the eddy correlation method at the 2.5 m height, while the condition of wind measurement was unsatisfactory because of the rooftop structures. The heat transfer coefficient, defined as the ratio of upward H under unstable condition and the temperature difference between the surface and the air, could be represented as a linear function of the mean wind speed.

Journal

  • 天気

    天気 49(11), 887-899, 2002-11-30

    日本気象学会

References:  9

Cited by:  2

Codes

  • NII Article ID (NAID)
    110001812874
  • NII NACSIS-CAT ID (NCID)
    AN00151568
  • Text Lang
    JPN
  • Article Type
    Journal Article
  • ISSN
    05460921
  • NDL Article ID
    6370684
  • NDL Call No.
    Z15-35
  • Data Source
    CJP  CJPref  NDL  NII-ELS  NDL-Digital 
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