農業気象
Online ISSN : 1881-0136
Print ISSN : 0021-8588
ISSN-L : 0021-8588
7 巻, 1 号
選択された号の論文の14件中1~14を表示しています
  • 武田 京一
    1951 年 7 巻 1 号 p. 1-3
    発行日: 1951/12/31
    公開日: 2010/02/25
    ジャーナル フリー
    A few years ago the author remarked in this Journal that in his and in Best's temperature profile measurement in the lowest layers of the atmosphere a systematic deviation from logarithmic law was observed. But as a precise wind velocity measurement was not simultaneously made then, the deviation could not be attributed to any reasonable source. Recently Pas will has published many simultaneous measurements of wind velocity, absolute humidity and air temperature in which the same systematic deviation from logarithmic law as described above is shown not only in temperature profile but also in wind and humidity profiles. This makes us expect that the deviations are due to a single source-probably, turbulence. Thus the author tries to explain the deviation in humidity profile by turbulence and shows a close agreement between the theory and the Pasquill's experiment both in stable and unstable atmospheres. But as regards temperature profile a systematic discrepancy between the theory and the Pasquill's experiment is found out in unstable condition though a close agreement is obtained in stable case. The disagreement may be due to radiation (e. g. the radiative transfer by Brunt) or a buoyancy term recently introduced by Priestley and Swinbank, but a closer computation is transfered till a next article.
  • 日下部 正雄
    1951 年 7 巻 1 号 p. 4-6
    発行日: 1951/12/31
    公開日: 2010/02/25
    ジャーナル フリー
    The author inquired into the seasonal change of soil moisture, by the data of routine observation at Owada, in 1948-1950. Under the influence of icepillar, the monthly mean of soil moisture in earth surface are very great in Jun and Feb., and they decrease in Spring. The second maximum in Jun. is the consequence of rainy season of “Bai-U.” In earth surface, the minimum of soil moisture appears in Jul. or Aug., then they increase gradually, and in winter they are in the most wet condition.
    The seasonal change of soil moisture of 5, 10 and 20cm. depth resemble each other. They are wet in winter, and dry in summer, and the second maximum observed in Jun. But the annual range in these layer is not so great, as in earth surface. Some seasonal change is recognised in 50 or 100cm. depth, but for want of data, the author can not discuss in defail.
    The author drawed the annual and monthly frequency curve of soil moisture. The monthly curvse of earth surface are classified in 5 typs, and those of 5 and 10cm. depth in 3 typs. In earth surface, the mean value of soil moisture are not coincide with the mode, but in 5 and 10cm. depth, they resemble each other.
  • 大後 美保, 丸山 栄三
    1951 年 7 巻 1 号 p. 7-8
    発行日: 1951/12/31
    公開日: 2010/02/25
    ジャーナル フリー
    We investigated about the effect of this protection against cold by covering it with the straw-matting at Owada-cho, in Saitama prefecture, from December 1950 to January 1951. Having covered the one of the two trees, whose diameters are 15cm, with the straw-matting and the other uncovered, we measured minimum temperature of trunk surfaces at 70cm height respectively. Its result is shown inTable 1.
    The relation between the temperature of the matted trunk (y) and the temperature of the uncovered trunk (x) is as the following equation. (see Fig. 1)
    y=1.85x0.87
    From the relation between (y-x) and x, in the Fig. 1, it was made clear that the effect of straw matting is most eff cacious when the temperature of the uncovered trunk is -6°C.
    The relation between the minimum temperature of the matted trunk (y) and the minimum air temperature at the meteorological observation field (x) is shown as follows; (see Fig. 2.)
    y=0.30+1.06x.
    By using this formula, the temperature of matted trunk is almost presumed from the air temperature at the meteorological observation field, and by it, it can be known whether the trunk needs more strawmatting or not.
  • 梅谷 博貞
    1951 年 7 巻 1 号 p. 9-10
    発行日: 1951/12/31
    公開日: 2010/02/25
    ジャーナル フリー
    As a result of the consideration on the dryness of the soil surface, the following formula is obtained
    y=y0e-Φ(T)t
    where, y is the soil moisture content on the soil surface, T the temperature of the soil surface, t the time measured counted by day in this case and y is a constant.
    From the data of the soil moisture content (1947-1950) except for the freeing periods at the Owada, Saitama, the following empirical formula is obtained by the least squares
    Φ(T)=1/10e-3.39+0.0T
    Using these results, it will be able to estimate the soil moisture content of the soil surface during the non-precipitation periods.
  • 鈴木 清太郎
    1951 年 7 巻 1 号 p. 11-12
    発行日: 1951/12/31
    公開日: 2010/02/25
    ジャーナル フリー
    水田土壤の水の滲透する場合の熱傳導を數學的に導き出して, 普通の熱傳導の數式を補正した。その結果は第一次近似計算では熱の傳播の位相は變らず, 振幅の減衰は少さくなるので熱がよく滲透することになる。唯この式と實驗とを照合して
    土壤の熱傳導度=0.0052
    土壤の熱傳比熱=1.0
    を得たのは方法として興味あることと思う。
  • (1)滲透と地中温度傳導率
    矢吹 萬壽
    1951 年 7 巻 1 号 p. 13-14
    発行日: 1951/12/31
    公開日: 2010/02/25
    ジャーナル フリー
    In this paper, the author studied on the relation between percolation and thermal diffusivtiy at paddy fields.
    The percolation of paady fields was measured by the lysimeter newly designed. (see Fig. 1.)
    1. The thermal diffusivity of percolated soil fields increases monotonously with the increase of percolation. The relation may be represented by β2=0.00285+6.08p
    2+5.08p (see Fig. 2.)
    where β2: virtural thermal diffusivity, α2: thermal diffusivity, p: velocity of percolation.
    2. The amplitude of diuraal veriation of the ground temperature decreasess with the velocity of percolation. (see Fig. 3)
  • (1) 風害研究のあり方について
    坪井 八十二
    1951 年 7 巻 1 号 p. 15-16
    発行日: 1951/12/31
    公開日: 2010/02/25
    ジャーナル フリー
  • 鈴木 清太郎, 吉田 美夫, 荒井 哲男
    1951 年 7 巻 1 号 p. 17-18
    発行日: 1951/12/31
    公開日: 2010/02/25
    ジャーナル フリー
    水蒸氣が露或は霜となるとき, 莫大の潜熱を放出する。若しこの物理學上の結果が周圍條件の室内と違う大氣中にも當てはまると假定すると, 霜は寧ろ有益で, 農家にとつて歡迎すべき現象である。
    田澤・荒井の2氏は樺太の野外に於いて南瓜葉の冷却曲線を得て, 結霜の場合はその冷却率は緩慢となるを指摘した。
    然し此の種の實驗では, 同一冷却状態に於て甲葉は結霜し, 隣接の乙葉は無霜となる裝置を考案せねば, その眞相を把んだとは言えないであろう。
    こゝでは豫備實驗として室内實驗を行つた。冷却法は氷と食鹽の寒劑をブリキ箱に入れてその底に葉を2枚はりつけたのである。A葉は硝子のシヤーレを以つて被い中に水を少量入れ, B葉も同樣硝子のシヤーレで被うが中は無水にするか或は吸濕物質を入れて, 乾燥するようにした。かくしてシヤーレを冷却すると, Bには霜が出來ず, Aには霜が出來る。Fig. 1は菜種の若葉について行つた實驗で, A葉は霜が出來たが, 被害少なく, B葉は結霜せずして被害が多い。又品種によつて被害程度が違う。
    次ぎに冷却曲線の研究は最初に硝子板について行つた。これは熱電對の1接點をA内の板に, 他の接點をB内に入れて, 起電力を自記するのであるから, かようにして得た冷却曲線は2硝子板の温度差である (Fig. 2)。
    Fig. 2によればある冷却點に達すると, 曲線は急に飛躍している。これはA内の硝子板上に出來た結露が過冷却の状態から, 潜熱を發して急に氷結したからである。
    Fig. 2は前者と違い, 霜の出來るA内に置いた甘藷の若葉上の絶對冷却曲線である。此の曲線の形は硝子板の場合と趣を可なり異にしている。次第に露が霜に變じているらしくもあるが, 又過冷却から潜熱を急に放つて氷結したようなところもある。
    これは事によると葉上の露と葉中の液汁とが僅かの時間を徑て次ぎ次ぎに結晶したのがも知れない。
  • 篠原 久男
    1951 年 7 巻 1 号 p. 19-20
    発行日: 1951/12/31
    公開日: 2010/02/25
    ジャーナル フリー
  • (1) 露の形成について
    荒井 哲男
    1951 年 7 巻 1 号 p. 21-23
    発行日: 1951/12/31
    公開日: 2010/02/25
    ジャーナル フリー
    The growth of dew formed on a glass-surface cooled by a freezing mixture was examined under varying conditions, the main results of which are as follows.
    1. The does not appear if the cooling surface is confined within a small box.
    2. When the surrounding air is colder than the glass surface, the dew does not form on it though the fog becomes conspicuously visible in the air.
    3. The derv formation does not seemingly enhance the evaporation from the water vessel placed near the glass surface. But when the circulation of a weak air current sets in and brings the moist air above the cooling surface, the dew is observed to deposit and causes water to evaporate to a greater extent.
    4. Though the cooling rate is kept the same, the enclosed glass surface always shows lower temprature than the open one and varies very little. It is however a remarkable fact that the dew forms on the former surface in very small quantity compared with the latter.
  • 1951 年 7 巻 1 号 p. 23
    発行日: 1951/12/31
    公開日: 2010/02/25
    ジャーナル フリー
  • (2) 煤紙による露の自記々録
    荒井 哲男
    1951 年 7 巻 1 号 p. 24-26
    発行日: 1951/12/31
    公開日: 2010/02/25
    ジャーナル フリー
    Dew and frost leave their traces on the sooted paper, when it is exposed to the nightly open air. This method made it possible for the writer to obtain a number of dew images made on various kinds of paper. And to bring about many interesting results.
    The writer arranged in grades several sorts of paper according to the degree of qualification of the dew recorder.
    The dew drop sametimes grows so large as to have a diameter of 1cm long during many hours. It is believed that the capillary action of the paper tissue can fully explain not only the formation of this large drop, but also many other features of dew images in the sooted paper.
  • 木村 吉郎
    1951 年 7 巻 1 号 p. 27-29
    発行日: 1951/12/31
    公開日: 2010/02/25
    ジャーナル フリー
    After the former report, I researched on the topographical deviation of prevailing easterlies in Aomori Prefecture during June, 1949 and obtained following results.
    (1) The mean wind directions (=x) of prevailing eastelies in June at iespctive five Pacific coastal points are almost the east as in table 1.
    (2) From the wind direction of the inland point corresponding to the coastal base point for the prevailing easterlies (=NE+ENE+E+ESE+SE) calculated by the method in table 2, the two vaules are derived: the standard deviation (=s) of the deviation of winds in angle and the difference of mean wind direction (=x) deviated at the inland point to the coastals as shown in table 3.
    (3) Making figure 1 with x-difference and s of deviated prevailing easterlies, and comparing the A, B and C groups in the former report, I considered that the prevailing easterlies deviate generally to south on the east side and to north on the west of the backboned mountain system of “Ou”, having probably the largest topographical effect in Aomoti Prefecture, by reason of the easterlies takes a roundabout route of the mountain system as shown in figure 2.
    (4) The larger the x-difference, the larger the s in general. The points having the larger two values are more apart generally to westward in the inland from the Pacific Coast of Aomori Prefecture.
  • 中馬 克己
    1951 年 7 巻 1 号 p. 30-32
    発行日: 1951/12/31
    公開日: 2010/02/25
    ジャーナル フリー
    1) I investigated the damage of sweet potato in the southern coastal region of Kagoshima caused by sea water which was brought by the typhoon Grace on 19 to 20, July, 1950.
    2) During this typhoon the amount of rain fall in the southern region of Kagoshima was very little in the first half and much in the latter half of the duration of the typhoon.
    3) In this region the brine was so concentrated as to do damage to the crop by the subsequent heavy rain-fall, while in the region far from the coast the brine was not only dilute, but washed away by the rain before it caused damage. This seemed to be the reason why the damage was restricted in the southern coastal region.
    4) Against the briny-wind, the leaves of sweet potato were less resistant than the wines. No injury was found on the roots, this may be due to the fact that the roots did not to the surface by the heavy rain.
    5) Owing to the small number of varieties observed, varietal difference of the damage was not determined, but as regards the power of recovery, Norin No. 9 seemed to be much strong.
    5) The degree of injury had much to do with the time of planting and consequently the rate of growth.
    The later the time of planting was, the more the damage was.
    7) In so far as the present investigation was concerned, no distinct relation between the direction of the ridge and the degree of damage was found.
    8) Damage was found to be reduced, in either wide or narrow range, on the leeward of such protection as slight elevation of the land, tea-plants planted around the field, windbreaks, lodges, and taros or soy-beans planted amony sweet potatoes.
    9) It is considered that the permanent measure to avoid the damage of briny-wind is to install the wind-breaks such as wood or fence.
    10) Planting of other crops which straw or stem is taller among sweet potato or between ridges, and determination of adequate time of planting and putting to use the ditch of ridge and direction of ridge will serve as a temporary measure to reduce the damage in question.
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