地学雑誌
Online ISSN : 1884-0884
Print ISSN : 0022-135X
ISSN-L : 0022-135X
75 巻 , 6 号
選択された号の論文の9件中1~9を表示しています
  • M. F. GLAESSNER
    1966 年 75 巻 6 号 p. 307-315
    発行日: 1966/12/25
    公開日: 2009/11/12
    ジャーナル フリー
  • 中村 和郎
    1966 年 75 巻 6 号 p. 316-325
    発行日: 1966/12/25
    公開日: 2009/11/12
    ジャーナル フリー
    The higher temperature in the city was ascertained in Nairobi, a city of the equatorial region, by analyzing the climatological data and by conducting temperature measurements in and around the city.
    Nairobi is a city with the population of 267, 000 (1962). It is located at 1°17' S on the East African Plateau gently sloping toward the east. The altitude ranges from 1, 800 meters in the west to 1, 600 meters in the east. The climate seems to be modified locally by the presence of forests in the wetter west where the average annual precipitation exceeds 1, 000 mm., and by the extensive grasslands in the drier east where trees are totally lacking with about 840 mm. of annual precipitation. The climate of the built-up area may be affected mainly by the density of buildings, the greater friction near the ground surface, and the thermal characteristics of concrete or asphalt. The warming effect through heating by combustion is thought to be negligible in an equatorial city. Dust is not thought to be enough to give such an effect to reduce insolation as is expected in a large city.
    The climatological data for three stations in and around Nairobi are available. The East African Meteorological Department at Dagoretti Corner (1, 798 meters above sea level) represents the western suburban area. The Eastleigh Air Port (1, 634 meters) is taken as a representative station for the urban area. Although it is located off the center of the city, there is no appropriate station in the city. The third station is the Nairobi International Air Port (1, 624 meters) representing the eastern suburban area.
    The city temperature is characteristically higher than the suburban areas in so far as minimum temperature is concerned. The difference between Eastleigh and the International Air Port reaches 1.3°C (Table 1). When compared with large cities in the higher latitudes, it is rather small. But the city center would make a greater difference.
    As for maximum temperature, there does not seem to be a conspicuous difference between the city and the suburbs. The city center has therefore a small diurnal range of temperature.
    Dagoretti is cooler than the International Air Port by 2.2°C for maximum temperature and by 1.3°C for minimum temperature. But the temperatures for the two stations can be plotted on the altitude-temperature line calculated for all the stations in Kenya (Fig. 2). The low temperature at Dagoretti may be accounted for by the altitudinal difference.
    It is also seen on the graph that the minimum temperature at Eastleigh is appreciably higher for the altitude, implying the urban effect.
    In order to know the simultaneous distribution of temperature in Nairobi, temperature measurements were conducted with a thermister-thermometer installed on a landrover. Temperatures were read at some 120 places in the city. Reduction had to be made to a certain time, for it took the author about one and half hours to complete a round trip of measurement. Figs. 3-6 are the distribution maps of temperatures thus obtained.
    Two warmest areas are always found on the maps. One is near the city center. But it does not always coincide with the area of the highest density of buildings. The vicinity of the Nairobi railway station is likely to be the warmest for some unknown reason. The other warm area is in the northeastern part of the city. Why this place is particularly warm-satisfactory explanations are not given for it.
    The high city temperatures are discernible even in the daytime. There is a relatively steep gradient of temperatures in the northern and western periphery of the built-up area. It is interesting to note, however, that the temperature gradient becomes extremely gentle at 9 p. m., when, it has been reported, nocturnal radiation begins to make a marked city-suburbs, temperature difference.
  • ゲラーシモフ I.P.
    1966 年 75 巻 6 号 p. 326-331
    発行日: 1966/12/25
    公開日: 2010/04/23
    ジャーナル フリー
  • 多田 元彦
    1966 年 75 巻 6 号 p. 332-336
    発行日: 1966/12/25
    公開日: 2009/11/12
    ジャーナル フリー
    岩手県雫石盆地に発達する新第三系の層位学的ならびに堆積学的研究を行なつておる途上, 岩手ポゾラン採石現場付近に発達する中新世上部の桝沢層上部から円錐形構造をもつたコンクリーション様のものを入手することができた。これは当時の堆積環境を知るうえに重要な手がかりになるものではなかろうかと考えて研究し, 次のような結果を得たのでこれを報告する。
    この円錐形構造をもつたものは湖成堆積物と考えられている桝沢層から発見されたが, これとよく形体が類似したクリンドリクヌスは海成堆積物から発見されている。
    この円錐形構造をもつたものはさや状の外壁と内部とからなつており, さや状の外壁は褐鉄鉱よりなり, 環状のふくらみをもつている以外は何も認められないし, 内部は硅藻質細粒凝灰岩からできており, セプタ状の下にくぼんだラミナが発達し, 褐鉄鉱のシミがついている。
    これにやや類似したものにディプロクラテリオンやリゾコラリウムがあるが, 内部構造, 外壁の形態, 軸の方向, 大きさ等にそれぞれ相異がみとめられ, 同一視することはできない。今までの文献にはこれと同一と考えられるものは著者の知るかぎりではみあたらないが, 不完全な標本なので命名を控えておく。
    生成環境は植物化石や淡水硅藻化石から湖成層であり, 現在と同じ高度であつたなら今より寒冷であつたと考えられる。その生成の水深度については決定する資料を持たないが, 桝沢層の上部から発見されている。
    成因については, 非常に困難ではあるが, 桝沢層の上部に発見される植物化石や亜炭砕屑物をもたらした樹木の幹・枝の内部が朽ちて, その後に堆積物が充填され, その外壁となる樹皮があとで褐鉄鉱によつて置換されたものと考えられるが, まだ確定的ではない。
  • 諏訪 彰
    1966 年 75 巻 6 号 p. 337-338
    発行日: 1966/12/25
    公開日: 2009/11/12
    ジャーナル フリー
  • 小林 貞一
    1966 年 75 巻 6 号 p. 338-339
    発行日: 1966/12/25
    公開日: 2009/11/12
    ジャーナル フリー
  • 小林 貞一
    1966 年 75 巻 6 号 p. 339
    発行日: 1966/12/25
    公開日: 2009/11/12
    ジャーナル フリー
  • 矢沢 大二
    1966 年 75 巻 6 号 p. 339a-358
    発行日: 1966/12/25
    公開日: 2009/11/12
    ジャーナル フリー
  • 貝塚 爽平
    1966 年 75 巻 6 号 p. Plate1-Plate2
    発行日: 1966/12/25
    公開日: 2009/11/12
    ジャーナル フリー
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