都市キャノピー内における冬季のCO<SUB>2</SUB>・温位・H<SUB>2</SUB>Oプロファイル Vertical profiles of carbon dioxide, temperature, and vapor within and above a suburban canopy in wintertime

Access this Article

Author(s)

Abstract

東京都大田区に位置する低層住宅街にある気象観測タワーを使用し,CO<SUB>2</SUB>・気温・H<SUB>2</SUB>O・風速・乱流の鉛直分布を2004年11月_から_12月まで計測した.大気安定度別に各スカラーのプロファイルを検討したころ,都市キャノピー内部で夜間の大気安定時にCO<SUB>2</SUB>が高濃度化するという興味深い現象を発見した.また気温分布と都市表面温度分布の計測より,屋根面で冷却された空気塊がキャノピー内部に堆積することを示唆する結果が得られた.本研究ではこの冷気流の存在とCO<SUB>2</SUB>の高濃度化と関連性について考察した.一方,H<SUB>2</SUB>OはCO<SUB>2</SUB>と異なる濃度分布を示しており,発生源の位置が濃度分布の形成に重要な役割を持つことを示した.

This study concerns the build-up of CO<SUB>2</SUB> within a suburban canopy under nocturnal stably stratified conditions. The results were derived from wintertime field measurements of the vertical profiles of CO<SUB>2</SUB>, air temperature, and turbulent flows. We examined the ensemble mean vertical profiles using the bulk Richardson number (Rb). Under stable conditions (Rb>5), the high CO<SUB>2</SUB> concentration within the canopy stayed at almost the same level, which indicates that the CO<SUB>2</SUB> emitted from the houses accumulated within the canopy. Such behavior was not found in the H<SUB>2</SUB>O profile. We argue that these profiles are influenced by subsiding cold air from the rooftop, thus drawing the high CO<SUB>2</SUB> levels from ventilation fans down towards the ground.

Journal

  • Proceeding of Annual Conference

    Proceeding of Annual Conference 18(0), 113-113, 2005

    THE JAPAN SOCIETY OF HYDROLOGY AND WATER RESOURCES

Codes

Page Top