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1 はじめに 工場や倉庫,住宅など低層構造物の耐風設計,ある いは高層ビルなど大規模建築物周りの風環境アセスメ ントなどにおいて,地表面近くの風速分布,乱れの強 さ,ガストファクターなど,自然風の性状を把握する ことは重要である。日本建築学会の建築物荷重指針・ 同解説(以下,荷重指針)では,地表面付近の風速の 性状が複雑であり,地表面粗度の影響を大きく受ける ことや,これまでに報告された実測例が少なく不明な 点が多いことより,周辺の地表面の状況に応じて定ま るある高さ Zb以下の範囲においては,平均風速,乱れ の強さを一定値としている。また,それ以上の高さで は,地上高さ Z の指数関数として与えている。したが って,これに基づいて算定した場合,Zbより低い構造 物の風荷重や地表面付近の平均風速を過大に評価して いることも多いと考えられる。 筆者らは,地表面粗度の状況が異なる複数の場所に おいて,地上高さ 10m までの 2 ないし 3 高度における 風速の観測を行う機会を得た。本報告は,それら実測 結果に基づき,地表面近くの風の性状について検討し

The authors et al. have developed a measurement system which can analyze meteorological data transmitted to E-mail servers from several observation sites.This measurement system is effective for observations made at remote places due to the utilization of the Internet. It also has an advantage in that the data is sent over the Internet in real time. This paper gives an outline of this system and describes observation examples obtained through its use.

Field measurements of winds on atmospheric corrosion for two important cultural properties were carried out.First, observations of a Buddhist statue were made. In the area where the statue is located, winds blow from the south or north most frequently. On rainy days, winds blow mostly from the north and during strong winds, winds are in most eases from the south. Due to this, it was presumed that northerly winds would cause pollutants and that southerly winds would bring salt particles from the sea to the Buddhist statue.Second, observations were made of a shrine as another important cultural property. Metallic parts of the shrine building corrode due to damage from salt. Although an analysis which is directly related to atmospheric corrosion has yet to he carried out, it was found that strong winds blow mainly from the sea in this area. Furthermore, the wind direction characteristics caused by the topographic features along the Sea of Japan in Shimane Prefecture were investigated by carrying out analyses of winds which include data obtained at several meteorological offices.