巻号一覧
52 巻 (1996 - 1997)
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52 巻, 3 号
選択された号の論文の4件中1～4を表示しています
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青野 靖之, 神田 英之, 張 暁川, 文字 信貴1996 年 52 巻 3 号 p. 221-231
発行日: 1996/09/10
公開日: 2010/02/25
ジャーナル フリーDistributions of heat budget terms of the forest in Mt. Ikoma area, located at the boundary of Osaka and Nara Prefectures, are analyzed using LANDSAT TM (Thematic Mapper) data. Sensible and latent heat fluxes are derived independently by the use of the bulk equations. In the bulk equation for sensible heat transfer at each pixel, surface temperature (provided by TM band 6 data), air temperature (interpolated according to elevation) and wind speed are used as variables. The bulk transfer coefficient is corrected using the bulk-Richardson number calculated from air and surface temperatures for each pixel. The moisture availability, wind speed, specific humidity of air and saturation specific humidity at surface temperature are used as variables in the bulk equation for latent heat transfer. The normalized difference vegetation index (NDVI) is used to estimate the moisture availability for each pixel. The bulk transfer coefficient for water vapor is assumed to be equal to that for heat.
TM data, sensed on August 6, 1990 is used to estimate distributions of heat budget terms in this study. The heat fluxes, averaged over the forest area, are estimated as 269Wm-2 for sensible and 256Wm-2 for latent heat, whereas mean estimations for net radiation and ground heat flux are 529Wm-2 and 42Wm-2 respectively. The mean value of moisture availability in the bulk equation for latent heat transfer is derived as 0.08. The distributions of sensible and latent heat flux in the forest area show that each flux on east side of mountain is greater than that on west side, because surface temperatures on east side are higher than those on west side approximately 2-3°C, due to the azimuth angle of the sun.抄録全体を表示PDF形式でダウンロード (8442K) -
鈴木 純, 中山 敬一1996 年 52 巻 3 号 p. 233-240
発行日: 1996/09/10
公開日: 2010/02/25
ジャーナル フリーIn the summer of 1994, drought injury in crops occurred due to high temperatures and low rainfall throughout Japan. In this study, the authors examined the characteristics of soil moisture condition and evapotranspiration to determine the water balance in a maize field during the drought.
The results are summarized as follows:
1) The total amount of soil moisture in the soil layer to a depth of 1.0m below surface throughout the growing season was less than the Depletion for Optimum Growth point (DOG). And soil moisture was reduced even at a depth of 2.0m, primarily because of the rapid development of the maize root system and water uptake.
2) Characteristics of the energy balance in the maize field during the growing season under the drought conditions in this study were different from results reported by others for other crops, for example the intensity of latent heat flux approximated net radiation flux, and sensible heat flux was nearly or less than zero.
3) Dry matter production, Total Digestible Nutrients and some other components were less in 1994 than 1995, when those values were comparable to values during a normal year, despite the similarities between the two years in the weather conditions for the growth of maize. This difference may be due to the difference in total amount of soil moisture below the soil surface to a depth of 1.0m at the conclusion of Baiu, the rainy season. In 1995, the soil moisture content was higher than DOG because of the high rainfall during Baiu.
4) On the bases of the above findings, the authors propose a simple irrigation method. When rainfall is insufficient at the end of the rainy season, fields are irrigated only once as soon as possible to attain the field capacity in the soil layer to a depth of 1.0m below surface.抄録全体を表示PDF形式でダウンロード (1087K) -
今 久, 洪 聖善, 松岡 延浩1996 年 52 巻 3 号 p. 241-245
発行日: 1996/09/10
公開日: 2010/02/25
ジャーナル フリーAn experiment was conducted to see how much the air temperature on the ground was cooled by the cooling of soil surface due to local watering. The day was fine and the soil was very dry, so the temperature of soil surface amounted to more than 50°C. But it was cooled by 20°C due to watering. The cooling of soil surface cooled the air on the ground. In the case of watering from 5cm radius to 5m radius, the cooling effect of soil surface attained to higher air layer according to the increase of watering radius. The height influenced: z (cm) was represented by the power function with the watering radius: r (cm). The relation is represented as the following function,
z=(r/6.39)1.03
The air on the ground was cooled by 6°C at the 1cm height and by 3°C at 10cm height by the watering of 5m radius. The cooling degree of the air temperature at each height was represented by the logarithmic function of the height.抄録全体を表示PDF形式でダウンロード (510K) -
近藤 純正1996 年 52 巻 3 号 p. 247-252
発行日: 1996/09/10
公開日: 2010/02/25
ジャーナル フリーPDF形式でダウンロード (729K)
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