巻号一覧
25 巻 (1969 - 1970)
- 4 号 p. 205-
- 3 号 p. 147-
- 2 号 p. 79-
- 1 号 p. 1-
25 巻, 4 号
選択された号の論文の9件中1～9を表示しています
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斎藤 隆幸, 永井 良典, 礒部 誠之, 堀部 淑子1970 年 25 巻 4 号 p. 205-214
発行日: 1970/03/25
公開日: 2010/02/25
ジャーナル フリーMeasurements of turbulence were carried out by use of a sonic-anemometer at several heights above and within a corn canopy with a mean height of 300cm. Turbulent intensity, autocorrelation coefficients, mixing length, transfer coefficient and energy spectra were computed for vertical and horizontal components of wind.
(1) Both √w′2 and √u′2 are in proportion to the mean wind velocity at each height. Above and in the upper part of the canopy, √w′2 is smaller than √u′2. In the middle part, √w′2 is nearly equal to√u′2 which may indicate the existence of isotropic turbulence.
(2) The autocorrelation coefficients above and within the canopy are calculated for vertical and horizontal components of wind fluctuation. Using the calculated values, the vertical mixing length and the transfer coefficient at each level are estimated respectively by the following equations
lw=√w′2∫T0Rwdt (1)
K=√w′2·lw (2)
where Rw is the autcorrelation coefficient for the vertical component of wind fluctuation, and T is the smallest time at which Rw becoms zero.
The values of both lw and K above the canopy agreed well with those calculated from the log-profile of wind velocity above the canopy.
The horizontal mixing length, lu is also calculated by use of the autocorrelation coefficient for the holizontal component of wind fluctuation.
Above and in the upper part of the canopy, lw increases with wind velocity, but it seems independent of wind velocity in the middle and lowest part. lu increases with wind velocity at any height above and within the canopy.
The transfer coefficient is, above and in the upper part of the canopy, in proportion to the square of the wind velocity, but, in the middle and lower part, is proportional to the wind velocity.
(3) With the values of τ and du/dz, lw which is defined by
τ=ρl2w(du/dz)2 (3)
is obtained, τ is the flux of momentum calculated from K and du/dz. The values of lw, from eq. (3) becomes in the canopy as large as three times of that at the top. It is therefore considered that equation (3) is not applicable in the canopy.
(4) Energy spectra of turbulence are estimated of vertical and horizontal components of wind fluctuation above and within the canopy. By expressing the spectra at high frequenciy end as
F(n)-np, (4)
the value of p increases with the gradient of wind velocity.
There are some developed peaks of n·F(n), which is probably due to local eddies created by plant.
A following equation is obtained for the vertical component of wind fluctuation at any height above and within the canopy
lw·nmax/u=0.08
where nmax is frequency at which n·F(n) is maximum.抄録全体を表示PDF形式でダウンロード (1234K) -
トウモロコシ群落内の拡散係数と葉面拡散速度内島 善兵衛, 宇田川 武俊, 堀江 武, 小林 勝次1970 年 25 巻 4 号 p. 215-227
発行日: 1970/03/25
公開日: 2010/02/26
ジャーナル フリー1967年の夏にトウモロコシ圃場で行なつた観測データを用いて, 作物群落内の拡散係数・葉面拡散速度・気孔拡散速度などの分布を明らかにすることを試みた。それらの結果を要約するとつぎのようになる。
1. 群落内の拡散係数の決定には熱収支法を使用した。拡散係数は表面から深さにつれて最初急に, あとはゆるやかに減少した。その模様は指数法則で近似でき, 減衰係数は2.46～2.88となり, 現在までの結果と一致した。しかし, 拡散係数の減少は気象条件によつてかなり変化することがわかつた (第3, 4図参照)。
2. 群落内における顕熱フラックスの変化と葉―気温差とから, 各層の平均的な葉面拡散速度(Df)を求めた。日中平均値は, 上層の3.8cm/secから中層の0.9cm/secへと, 深さにつれて減少した。深さに伴うDfの減少は指数函数で近似でき, 減衰係数は2.8になつた。Dfは周辺空気中の拡散係数につれて増加し (第6図参照), 比例係数は1.25×10-3となつた。これは現在までの値より若干大きい。
3. 葉面拡散速度と蒸散についての有効拡散速度とから, 気孔拡散速度を求めた。気孔拡散速度は群落上層から深さにつれて減少するが, それは正午頃において特に著しかつた。日中平均値は上層の0.29cm/secから中層の0.11cm/secへと約1/3に減少した。これは指数函数で近似され, 減衰係数は2.29となつた。上層葉の拡散速度と入射全波放射との間には双曲線的関係が見出された (第8図参照)。これは室内実験の結果とよく一致している。
4. 水蒸気フラックスの垂直分布と葉面積密度分布とから, 各葉層の蒸散強度を求めた (第9図)。蒸散強度は深さにつれて減少した。群落上層のそれは朝方の1×10-6から正午頃の3×10-6へと増加し, 午後は減少して1×10-6g/cm2sec以下となつた。各層の蒸散強度と純放射量 (水平面) との間には双曲線的関係が見出された (第10図)。群落内の水蒸気場のシミレーションで重要な役割を果す葉面相対湿度は上層の0.6～0.7から中層の0.7～0.8へと増加した。午後おそくには, 葉面相対湿度の高度変化は弱くなつた。抄録全体を表示PDF形式でダウンロード (1878K) -
武智 修1970 年 25 巻 4 号 p. 229-232
発行日: 1970/03/25
公開日: 2010/02/25
ジャーナル フリーThe intact measurement of leaf moisture is attempted with the transmission of beta radiation.
Transmitted radiation intensity I (cpm) is approximately represented by
I=α·I0e-μMt(1+u), (1)
where α=geometrical efficiency of the detection of transmitted beta radiation
I0=incident radiation intensity (cpm)
μ=mass absorption coefficient (cm2/mg)
Mt=mass thickness of dry tissue of the leaf (mg/cm2)
u=moisture ratio of the leaf.
The moisture ratio of citrus leaves was measured using 204Tl as the beta ray source. The leaf was placed between the source and the detector, a G-M tube. In the course of drying the leaf was weighed and the transmitted beta radiation was counted.
Absorption curves of the beta radiation by a citrus leaf versus the moisture ratio showed that equation (1) is valid in the mass thickness range from 22 to 37 mg/cm2.抄録全体を表示PDF形式でダウンロード (487K) -
上村 賢治, 久保 祐雄, 小沢 行雄1970 年 25 巻 4 号 p. 233-239
発行日: 1970/03/25
公開日: 2010/02/25
ジャーナル フリーRecently so-called “Graft Carbon Sheet Heater” is produced. It is a sheet of electric resistance, that is made of glass-cloth, on which carbon black with a certain vinyl-monomer is glazed at 160°C-180°C for ca. 10 minutes.
The graft carbon sheet heater has the following characteristics:
(1) There is the clear tendency to increase in resistance with time.
(2) The surface temperature of the graft carbon sheet heater at the balanced situation is different after the setting conditions;
(a) on the concrete floor ca. 20°C
(b) on the surface of the sand bed ca. 40°C
(c) 15cm underground ca. 60°C
(3) At the balanced situation the constant temperature gradient can be found in the sand bed and the certain temperature can be observed at the certain centimeter underground.
(4) The raising effect of the gaft carbon sheet heater for the air-temperature is expected especially in a vinyl-hause.抄録全体を表示PDF形式でダウンロード (2889K) -
羽生 寿郎, 内島 立郎1970 年 25 巻 4 号 p. 241-246
発行日: 1970/03/25
公開日: 2010/02/25
ジャーナル フリーAn index of the climatic productivity of paddy rice was firstly proposed by Murata (1964) using the average of daily mean air temperatures and that of daily insolation amounts during the productive period of rice of 40 days from 10 days before to 30 days after heading time. However, the yield is affected by climatic conditions during the whole growing period of the plants. Therefore, we attempt to look for the index which contains climatic elements covering the whole growing period. We already analysed the relationships between climatic conditions (air temperature and duration of sunshine) and ripening with in 40 days after heading time, and obtained a climatic index ripening, YG.
In this report, we have analysed the relationships among the rice yield, the daily mean air temperatures, θ6·7 and the total durations of sunshine, S6·7 by Jordan's recorder in the main growing areas in the northern districts of Japan for June and July, namely, transplanting period and heading time. Yield is affected considerably by θ6·7, but not by S6·7, as shown in Fig. 1. Thus, the lowest critical conditions of rice yields, 400, 500, 550kg/10a, could be obtained from the relations among θ6·7, S6·7 and yeields in Fig. 1, a yield of 500kg/10a may not be attained below the critical curve of 500kg/10a at all.
Further, the relationship between θ6·7 and YG is analysed, and a θ6·7-YG co-ordinate which indicates the climatic conditions during the whole growing period is constructed. The climatic data of each area in the northern districts of Japan in recent years are plotted on this coordinate with yield data. Three critical curves mentioned above are obtained using the same method as in Fig. 1 (Fig. 2). Fig. 3 shows the relative situation between the values of the co-ordinate for normal years in these areas and the critical curves. It is considered that the greater is the diffeerence of the relative situations between the normal yield and the critical curve, the greater is degree of inhibition of yield by other factors than climatic ones.抄録全体を表示PDF形式でダウンロード (842K) -
武田 京一, 塩月 善晴1970 年 25 巻 4 号 p. 247-255
発行日: 1970/03/25
公開日: 2010/02/25
ジャーナル フリーRecently, also in the warm region Kyushu, which is situated in the south-western area of Japan Islands, a local snowfall has become one of the important meteorological phenomena in winter, since snowfalls have many influences upon agriculture, trasportation, especially in the high-way road which nowadays is going to develop, water resources and so on. The authors have investigated snowfalls by means of the climatological analysis and general synoptic analysis, and had a chance to observe the natural snow crystals and snowflakes associated with the snow clouds developed in the north-west monsoon period, Feb. 5th to 7th in 1969. The snow crystals and flakes were observed with the method of the macroscopic sketch, the replica observation, the close lens camera, and the photographic recording. By those analyses described above it is found that when we have much snow in Kyushu where usually the snowfall occurrence is very rare and its amount is very little, the synoptic conditions and the pattern of snowfall distribution are quite similar to those when the heavy local snowfalls occurred in the coastal regions of Japan Sea. Results of analyses are summarized as follows.
1) In large scale synoptic situation, when the cold and dry air mass from the Siberian Continent comes down southward near the northern part of Korean Peninsula and then passes over the Japan Sea, it is modified with heat and vapor from the sea water below and becomes an unstable air mass.
2) The occurrence of snowfall is characterized by the strong wind zone near the 850mb level. This corresponds to the strong curvature of wind profile explained previously by Higuchi.
3) In meso scale synoptic situation, local lines of convergence appear along the north and south-west coast of Kyushu. Those are made due to the cooling effect of radiation in the inland area and increases in the rate of precipitation.
4) Types of Radar Echoes observed support that the snow clouds are convective ones and show their band structure which is characteristic to local heavy snowfalls in Hokuriku and Hokkaido.
5) Snowfall distribution shows that much amount of preciptation is seen rather in the lower plain, and this is quite similar to local heavy snowfalls in the coastal region of the Japan Sea.
6) Snow crystals observed at Mt. Hiko are almost consistent with the expected ones by Nakaya's Ta-S diagram.抄録全体を表示PDF形式でダウンロード (4164K) -
坂上 務1970 年 25 巻 4 号 p. 257-265
発行日: 1970/03/25
公開日: 2010/02/25
ジャーナル フリーThe agriculture in Japan, especially in western Japan, suffers from flood damages.
In this paper the author investigated the property of the heavy rains during the period from 7th to 10th of July 1967, recording the total amount of precipitation over 300mm in the north-western Kyushu, including the region of Nagasaki and Saga prefectures. Many severe flood damage landslides and their related damages occurred owing to the rainfalls.
The results of the investigation from the standpoint of the local scales are as follows:
(1) The heavy rains are composed of concentrated heavy rain caused by mesoscale disturbances passing along the Baiu front and of that associated with a low pressure.
(2) The rain area is composed of 3 zones which stretched out from western Nagasaki to the Seburi mountains. The scale of rain cells (area) is about 10 to 20km in diameter and their intensity are at most 20-40mm per 10min.
(3) In the later part of this paper, the author makes a survey of landslids, and occurrence of landslide related to the rainfall. The author suggests that the landslides are more closely related to heary rainfalls of 20mm/10min than hourly and daily rainfall.抄録全体を表示PDF形式でダウンロード (6380K) -
日下部 正雄1970 年 25 巻 4 号 p. 267-274
発行日: 1970/03/25
公開日: 2010/02/25
ジャーナル フリーPDF形式でダウンロード (1282K) -
1970 年 25 巻 4 号 p. 283
発行日: 1970年
公開日: 2010/02/25
ジャーナル フリーPDF形式でダウンロード (119K)
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