巻号一覧
27 巻 (1971 - 1972)
- 4 号 p. 123-
- 3 号 p. 79-
- 2 号 p. 37-
- 1 号 p. 1-
27 巻, 4 号
選択された号の論文の6件中1～6を表示しています
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横田 廉一, 高橋 英紀1972 年 27 巻 4 号 p. 123-128
発行日: 1972/05/25
公開日: 2010/02/25
ジャーナル フリーIn this paper, we compared the distributions of horizontal wind speed measured in a region of complicated configuration to those of its model area in the wind tunnel.
The results obtained may be summarized as follows:
(1) In the model test with 1/1000 reduced scale of the field, the distributions of the wind speed at 1.0mm height in the model area had a good similarity to that of 1.0m height in the field.
(2) The wind erosion has happened at two areas in this field (Fig. 1). The results of its model test in the wind tunnel showed that the wind erosion in area (D) and area (E) were caused by SW∼W wind and S wind, respectively.
(3) At first we predicted that the wind was converged by the shelter belt (I), consequently the wind erosion was brought about at the area (E) in the field. However, it was cleared that removing the shelter belt increased the wind speed at the area (E) and expanded the area of wind erosion on the model test of wind tunnel.抄録全体を表示PDF形式でダウンロード (2533K) -
礒部 誠之1972 年 27 巻 4 号 p. 129-135
発行日: 1972/05/25
公開日: 2010/02/25
ジャーナル フリーSignals from two uni-directional sonic anemometers at different levels in the canopy of mature corn of 3m high have been analysed with the method of “fast Fourier transforms” to yield energy and cross spectra and cross correlation coefficients. The spectral analysis reveals the formation of characteristic components in a frequency range of 0.11Hz to 0.18Hz. These compoments are shown to travel upward at least above a level of 85cm. The components in a range below the characteristic band of frequency seem to move downward. The cross correlation coefficients with time delay indicate that on the average the fluctuations of wind velocity travel upward and that the travelling speed increases with mean wind speed in the vegetation.
A constant-temperature hot-wire anemometer has provided the data for the energy spectra in a frequency range of 1Hz to 50Hz and their variations with level and wind speed condition in the vegetation. The spectra disclose the excitation of distinctive frequency components under moderate to strong wind conditions. Supplementary measurements of energy spectra of turbulence behind cylinders and plates in a wind tunnel and their comparison with the spectra in the corn provide an interpretation for the distinctive components to be due to stems of the corn. No conspicuous extremals which could be attributed to leaves are found in the spectra.
For details, reference should be made to: Isobe, S. (1972) A spectral anlysis of turbulence in a corn canopy. Bull. Nat. Inst. Agric. Sci. (Japan), Ser. A, No. 19, 101-113.抄録全体を表示PDF形式でダウンロード (733K) -
真木 太一1972 年 27 巻 4 号 p. 137-143
発行日: 1972/05/25
公開日: 2010/02/25
ジャーナル フリー南極の昭和基地で, 著著は, 風速の垂直分布については, 1970年3月より9月までと, 気温の垂直分布については, 1970年3月より1971年2月まで観測を行なつた。
観測結果を要約すると次のようになる。
(1) 気温傾度の頻度分布は, 年間では約75%, 冬期間だけでは約88%が安定状態であり, 冬季7・8月の分布範囲は広く, 夏季のそれは狭くなつている。春季 (10・11月), 秋季 (3・4月) では左右対称に近い変化を示しており, 冬季 (5～9月) では, 不安定側に夏季 (12・1・2月) では, 安定側に急減している。
(2) 逆転層発生時のみの平均気温であるTx, T20, T1の変化にも Kernlose type 現象がみられる。ここでTxは対流圏最高気温, T20とT1は20mと1m高度の気温である。冬季には, Tx, T20, T1の較差が顕著に大きくなつている。
(3) 南極では, 夏季を除けば, 逆転層の厚さが大になると逆転層の発生率は低くなり, 逆転層の厚さが小になると発生率は高くなる。
(4) Tx-T1, T20-T1, T10-T1の順に気温較差は小さくなり, その値は冬季7月が最大で, 夏季1・2月頃が最小になつている。
(5) (T10-T1)/(T20-T1) の変化は, 秋季に高く, 夏季に低く, 冬季と春季ではほぼ同じ値を示している。この理由は, 冬季と春季では, 気温の垂直分布が直線的に変化するためであり, 秋季では, 接地下層部の気温傾度が急激に増加するためであり, 夏季では, 下層部の気温傾度が急激に減少するためである。
(6) 風速と気温傾度の最大臨界値の関係は, 直角双曲線に近い変化を示していて, 5m/sec以下では急激に気温傾度が増加しており, 8m/sec以上では, 地吹雪発生のため減少している。抄録全体を表示PDF形式でダウンロード (964K) -
吉野 正敏, 星野 光子, 大和田 道雄1972 年 27 巻 4 号 p. 145-152
発行日: 1972/05/25
公開日: 2010/02/25
ジャーナル フリーThe total area of wind breaks reaches 37, 629 ha in Hokkaido in 1969. In order to rearrange the wind breaks, it was hoped to study the distribution and the density of wind breaks in relation to local wind conditions. Here, an example of the studies in the Shari-Abashiri region is reported.
The writers made firstly investigations into the density and the prevailing directions of wind breaks through interpretation of air photos and secondly field observations of wind-shaped trees, such as Larix leptolepis, Fraxinus mandshurica and Populus spp., as an indicator of the local wind conditions. The following results, as given in the figures attached, were obtained: The Shari-Abashiri region studied can be divided into three from the viewpoint of wind conditions. They are; i) the northern foot region of Mt. Shari, ii) the coastal region and the marshy region along the Shari River, and iii) the hilly region between the cities, Koshimizu and Kiyosato.
The characteristics of each regions are: In the first region, the density of wind breaks is 100m/ha on the average with the maximum 150-200m/ha. The southeasterly winds prevail up to 100m above sea level on the foot as called “Sharidake-oroshi (fallwind from the Mt. Shari)”, which blows especially in spring. The direction of the wind breaks are mainly from SW to NE. In the second region, the density of wind breaks is lower than 25m/ha. This coastal region is lower than 20m above sea level and has 2-3km width. There prevail the northerly winds from the Sea of Okhotsk. Where the marshy, low land extends 8-10km inland from the coast, the northerly winds invade into there. In the third region, the density of wind breaks is mainly 50-75m/ha. Almost all wind breaks run in W-E direction. The prevailing wind directions are southerly, but northerly in an exceptional year with cool summer, like in 1971.抄録全体を表示PDF形式でダウンロード (3548K) -
(1) 防風垣後方の気温の分布横田 廉一, 高橋 英紀, 萩原 守1972 年 27 巻 4 号 p. 153-158
発行日: 1972/05/25
公開日: 2010/02/25
ジャーナル フリーIn order to make clear the influence of shelter-hedge upon thermal conditions of cultivated fields, measurements of wind and temperature profiles were made in the lee of model windbreaks. Experiments were made in a wind tunnel as shown in Fig. 1 and on a plowed field. The geometrical sizes of model shelter-hedges and the hydraulic charactriestics of underlying surfaces are shown in Table 1. The results obtained are summarized as follows:
1. The similitude between phenomena observed in the wind tunnel and field experiments was examined by the following relations proposed by Inoue (1959) and Nemoto (1961, 1967) for wind profile in the surface air layer
HN/HM=ZON/ZOM, UN/UM=(HN/HM)1/3
Relationships among wind speed, roughness and height of shelter-hedge used in the experiments satisfied approximately the relations mentioned above, indicating that the results obtained in wind tunnel experiments may be applicable to field conditions.
2. Fig. 4 indicates clearly that the vertical distribution of air temperature in the lee of the shelter-hedge (closeness 100%) is not very affected by thermal stratification in air flow. However, the distribution pattern of air temperature in the lee of the shelter-hedge (closeness 100%) changed considerbly by wind speed as shown in Fig. 5. Especially, the temparature profiles observed in field experiments (N) was much affected by wind speed.
3. The temperature rising effect of shelter-hedge was studied in relation to the closeness of sheter-hedge in the wind tunnel. The model shlter-hedges with the closeness of 100, 60, 50, 40 and 30% were set in the wind tunnel and temperature profles in the lee of these shelter-hedges were measuried by using thermocouples. Two-dimensional distributions of air temperature as shown in Fig. 7 indicate that the temperature rising effect is highest in the lee of shelter-hedge with closeness of 60%.抄録全体を表示PDF形式でダウンロード (731K) -
内陸部への吹走にともなう各気象要素の推移について佐々木 信介, 卜蔵 建治1972 年 27 巻 4 号 p. 159-163
発行日: 1972/05/25
公開日: 2010/02/25
ジャーナル フリーSimultaneous observations at 4 points were made in July, 1970 in the plain of the Oirase river, Aomori prefecture in order to investigate the characteristics of Yamase wind.
The observational stations were established, one at the seaside and the other three on some rice fields of inland at distances of 4, 12 and 28km from the coast respectively. Observations were made for micrometeorological elements in general up to the height of 1m above the ground.
The effects on Yamase wind passing from coast over inland were generally slowing down of the velocity, the humidity and water drops in the atmosphere were decreased, and the temperature rose.
The air temperature at a linear distance of 10km from coast was about 2°C higher than that of the coast. The rate of increase in air temperature was affected by solar radiation energy.
When Yamase wind is broken up by obstructions like houses and trees, the wind velocities and water content in the atmosphere are significantly affected.
At the base of the mountains the thickness of layer of clouds increased. Furthermore the solar radiation energy decreased and the air temperature was lower during heavy Yamase wind.
It was considered that these phenomena were influenced by the location of the mountain.抄録全体を表示PDF形式でダウンロード (3037K)
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