Study on Environmental Conservation in Suo Nada Region (1st Report) : Stream Line Analysis and Investigation on Atmospheric Diffusion near the Ground in a Small Scale Headland

周防灘地域の環境保全に関する研究〔I〕 : 局地風の流線観測と螢光微粒子による拡散実験

Study on Environmental Conservation in Suo Nada Region (1st Report) : Stream Line Analysis and Investigation on Atmospheric Diffusion near the Ground in a Small Scale Headland

Creators Fujiwara Teruo

Creators Motoda Yushiro

Creators Shiotsuki Yoshiharu

Characteristics of the wind structure near the ground and the atmospheric diffusion on small scale headland (Chigasaki, Saga Pref., 1000m. 800m) are investigated by means of flag net-work observation (for the former) and the fluorescent particle (F. P.) tracer technique (for the latter) for Jul. 10-16,1969. Results of stream line analysis and the comparison of the observed particle concentration by rotor rod samplers network with the calculated ones by the diffusion equation of the continuous point source and Pasquill's formula, are as follows : 1) When south-western wind is stronger than 5m/s, the vertical wind fields are often appeared at the southern part of the headland. 2) In other west and north-estern wind field, vortex are not appeared so much as in the south-western wind. 3) In this investigated headland where is very abundant in bushes and ups and downs of terrain, the values of observed F. P. concentration do not agree so well with the calculated values by the diffusion equation (Eq. 3) and Pasquill's formula as the hitherto results in the open flat region. But taking into account of the accuracy of the observed values, the availability of Pasquill's formula is comparatively recognized even in such a small scale region. 4) The values of F. P. concentration are extremely small at the downwind part of hill, the area of bushes and the valley. Accordingly, the atmospheric diffusion near the ground is much influenced by the effect of terrain and roughness of the ground surface.

[ISSN]0372-7661

[NCID]AN00244228