足尾山地北部の山地斜面において,凍結・融解による斜面物質の地表下移動を調べた.凍結・融解による斜面物質の移動とその他の原因(温度・水分変化など)によるものとは,変位の方向や変位量などの点でかなり異なる.融解時における斜面物質の移動は,凍結時の氷晶分離析出の結果生成される土塊の変位によるもので,この土塊は地表下の融解しつつある層のなかを中間移動すると考えた.凍結・融解によって生じる斜面物質の変位量の垂直分布パターンは四つのタイプに分類される.そのうち,斜面下方への変位を示す三つのタイプのパターンの差は,融解時における各深さの中間移動の程度の相違を示すと考えた.また,凍結・融解による斜面物質の斜面下方への変位量は,傾向として,最大有効角(32°～37°)で極大値を示すことが明らかになった.

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山地内での各種の営力による土砂流送の平均的な機構を示す式が,掃流砂量式の一般形
Q_B=Cτα(Q_B:掃流砂量,τ:掃流力,C,α:定数)
によって近似できるものとし,これと流れの連続式などから導いた斜面の縦断形変化を記述する式(Mizu-tani,1974)により得られる計算値と,実際の山体の侵食量の測定値とが最もよく一致する条件を求めた結果,α=3～3.5が得られた.従来の掃流砂量式のαは,ほぼ1～2.5である.
α=3.3とした場合の斜面変化を記述する式により,山体の侵食速度を反映している地形要因を求め,断層崖や谷壁の発達について考察した.また,開析が進んでいる流域の主谷の縦断形が,対数関数で示されることを水系網の法則から導き,モデル縦断形,断層崖の開析谷および火山放射谷の縦断形が分水界の位置を適当に移動させることによって,片対数グラフ上でほぼ直線になることを示した.

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表題の地域において,1968年8月23日から29日までの期間,砕波後の波の遡上について経日的に測定した.その測定の結果から,(1)相対遡上高と深海波の波形勾配との関係を調べ,従来,主として造波水路で実験的に求められてきた両者の関係と比較し,実測値と実験値との差異について検討した.(2)遡上距離と砕波の波高との関係を調べ,Waddell,E・が米国のSantaRosa島の海岸で測定した両者の関係と比較し,両地域の間に生じた差異の原因について,両地域の海浜の地形や海浜砂などの特性から一応の説明を試みた.

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The objective of this study is to clarify some of principal factors which influence the variations and minute regional differences in the concentrations of air pollutants. The “Factor Analysis” method, which has been developed in psychology, was applied to the data on sulphur dioxide concentrations at nine stations in and around Sendai (Fig. 1) during the period from December, 1972 to February, 1973.
First, mean and maximum daily concentrations were analyzed, and the result was con-firmed with hourly measurements at three hour intervals. Two main factors were extracted by the computation (Tables 1 and 3). Then, the author attempted to examine the meanings of the extracted factors by means of the distribution of factor loadings (Figs. 4, 5, and 7), the time variation of factor scores (Figs. S and 9), and the correlations between factor scores and some of the meteorological elements (Tables 2 and 4). The meteorological data used for this purpose were as wind direction, wind speed, vertical gradient of temperature, solar radiation, and precipitation observed at the Sendai District Meteorological Obse-rvatory and the Yagiyama station.
The results obtained are as follows;
1) The first factor accounts for a large part of the variations in concentrations. Its loadings are plus everywhere, and the scores for them have negative correlation coefficients to wind speed and vertical gradient of temperature. These negative correlations indicate that the scores are higher under a calm and stable atmospheric condition, that is, the concentrations can be expected to be higher all over. Sendai under such a condition. Therefore, the first factor, the air pollution potential, is regarded as a condition which stagnates the pollutants over the large area.
2) The second factor mainly accounts for the local variations in the built-up area where medium and small emission sources are concentrated. The factor scores have positive correlation coefficients to wind speed and lapse rate. But, their values are generally lower on Sundays and higher on weekdays when a windy and unstable atmospheric con-dition; therefore, the second factor is considered to be conditioning wind-blown pollution.
3) Loadings of the second factor in the built-up area exceed those of the first factor as far as daily maximum value is concerned ; that is, higher concentration in the built-up area is closely related to the second factor. This indicates that, at any place in the vicnity of emission sources, higher concentrations tend to be accompanied more frequently by high wind speed and unstable lapse rates rather than by stable and calm atmospheric conditon.

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