巻号一覧
54 巻 (1998)
- 4 号 p. 315-
- 3 号 p. 225-
- 2 号 p. 125-
- 1 号 p. 1-
54 巻, 3 号
選択された号の論文の7件中1～7を表示しています
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グリーン アランエドウィン, 林 陽生1998 年 54 巻 3 号 p. 225-234
発行日: 1998/09/15
公開日: 2010/02/25
ジャーナル フリー近赤外線の揺らぎを測定して境界層の顕熱フラックスを評価する手法(シンチレーション法)と渦相関法を組み合わせ, 水稲田における各種フラックスの観測を行った。シンチレーション法の最大の特徴は, 近赤外線のパスを長く設定することによって, 広範囲の地域を対象としたフラックスの測定が可能な点にある。本研究では, パスの長さを320m, 高度を水稲群落上約1mに設定した。近赤外線の屈折を引き起こす要因は主に気温の不均一性であるが, 水稲群落上のように湿潤な状態では湿度の効果が無視できない。始めに, 湿度の効果について理論的に導いた。観測期間中の天候は晴れ時々曇りでボーエン比は0.3以下の非常に湿潤な状態であった。解析の結果, 日中のリフラクティブ・インデックス(揺らぎの規模の指標)は夜間のそれより小さかった。観測結果を30分平均値に整理し, シンチレーション法と渦相関法による顕熱フラックスを日中と夜間について比較したところ, 安定条件によって異なる関係が現れた。すなわち, シンチレーション法による値は日中の不安定条件下では過小評価となり, 夜間の安定条件下では過大評価となった。これらの結果はWeseley(1976)の指摘と一致するものの, シンチレーション法においては水蒸気による近赤外線エネルギーの吸収効果の影響について今後考察する必要があると考えられた。抄録全体を表示PDF形式でダウンロード (3271K) -
米村 正一郎, 矢島 正晴, 酒井 英光, 諸隈 正裕1998 年 54 巻 3 号 p. 235-245
発行日: 1998/09/15
公開日: 2010/02/25
ジャーナル フリーRice yield was estimated at all the third mesh points in Japan for the condition of elevated CO2 concentration and increased temperature with a growth model. Growth parameters of the model for 36 principal Japanese japonica type varieties were employed for the calculation. In cases of the temperature change in -2, +2 and 4°C, decrease of the total yield of Japan was estimated to be about -14, -5 and -12%, respectively. Under the conditions with temperature increment of 2°C, only rice yield in Hokkaido rose. In central and southern part of Japan, rice yield decreased as the temperature rose, however, the reduction could be avoided by advancing the planting date.
Effect of CO2 concentration on rice yield was incorporated into the radiation use efficiency which was calculated from light-photosynthetic curves of canopies in growth chambers. Rice yields increased from 10 to 15% depending on the radiation intensity when CO2 concentration was elecated from 350ppm to 1200ppm. Under the lower the radiation intensity, the increase of rice yield caused by elevated CO2 concentration was higher.抄録全体を表示PDF形式でダウンロード (6156K) -
丸山 篤志, 大場 和彦, 黒瀬 義孝1998 年 54 巻 3 号 p. 247-254
発行日: 1998/09/15
公開日: 2010/02/25
ジャーナル フリーA simple model to estimate the daily mean water temperature of paddy fields from observed meteorological data was developed. The model is based on a crop growth model coupled to an equilibrium water temperature model. Using this model, the water temperature of a paddy field can be estimated from only three factors namely, air temperature, solar radiation, and water vapor pressure, observed a nearby weather station. Validity of the model was examined on actual paddy fields of different style of cultivation, under warm temperate climate. There was a good agreement between observed and calculated temperature. This suggests that the water temperature of paddy fields can be estimated well using this model without any correction to adjust for the style of cultivation.
The model was applied to estimate the water temperature of paddy fields under normal and abnormal weather conditions. Under normal weather conditions, there were regional differences in water temperature of paddy fields caused by the differences in elevation and cultivation period of paddy fields. Under abnormal weather conditions, the deviation from normal of water temperature was directly proportional to the deviation from normal of air temperature. A 1.0°C decrease in air temperature during a cool summer year corresponded to a 1.0°C decrease in water temperature of paddy fields, whereas a 1.0°C increase in air temperature during a hot summer year corresponded to a 0.6°C increase in water temperature of paddy fields.抄録全体を表示PDF形式でダウンロード (2816K) -
真木 太一1998 年 54 巻 3 号 p. 255-266
発行日: 1998/09/15
公開日: 2010/02/25
ジャーナル フリーAn investigation was carried out at the Jagaramogara basin in Tendo, Yamagata from 1996 to 1997. Obtained results are as follows:
(1) There are wind caves or holes with changeable wind direction, blowing out cool air from the holes in summer half year of May to October and drawing in cold air in winter half year of November to April at the basin bottoms of Ohjigoku and Shimojigoku in Jagaramogara. The author found that the entrances of wind in summer and exits of wind in winter are the stone holes from the region below the cliff of Amayobari west slope to the region fallen down on upper Murakumonoike, and also found that the same regions mentioned above are the entrance in summer and the exit in winter including with the upper holes of the sloped area at Shimojigoku basin.
(2) The hole air temperature was observed 0°C at the end of May, 2 to 3°C with relative humidity of 100% and wind speed of 1.5m/s from July to August, maximum of 5.3°C in the middle ten days of October and minimum of -5.4°C in the last ten days of January. There are ices in the wind cave at least until June. The air temperature of blowing wind from the hole in summer is low based on the conduction heat contacted from the ice to air and by cooling of sublimation, fusion and evaporation heats.
(3) Inversion of air temperature frequently appeared at night from autumn to spring and is fairly even at the daytime in summer. Strong cooling continued for a long period by adding to the cold air lake with temperature inversion and to cold air blowing out from the holes of basin bottom under a proper condition.
(4) The cold air current being relatively dry and warm is observed and typical wind speed is fairly strong of 2.0 to 2.5m/s. The air current starts to blow from the elevation 760m on Amayobari Mt., slides down on the slope and joins in the basin. The cold air lake is developed by radiation cooling. The thermal belt appeared at the elevation of 560 to 570m.
(5) The plant profile indicates the reverse distribution to elevation which the semi-alpine plants of dwarfing with cold-drought resistance are found near the lower part of basin. There are many plant species, but the number of holes were decreased recently.抄録全体を表示PDF形式でダウンロード (3771K) -
卜藏 建治1998 年 54 巻 3 号 p. 267-274
発行日: 1998/09/15
公開日: 2010/02/25
ジャーナル フリーPDF形式でダウンロード (1112K) -
邱 国玉, 籾井 和朗, 矢野 友久, 佐瀬 勘紀1998 年 54 巻 3 号 p. 275-282
発行日: 1998/09/15
公開日: 2010/02/25
ジャーナル フリーENWATBAL (ENergy and WATer BALance)は, 土壌蒸発量(E)と植物蒸散量(T)を計算する数値モデルである。本研究では, このモデルの裸地圃場とソルガム群落圃場への適用性について検討した。裸地におけるEの実測値と計算値を比較した結果, ENWATBALモデ
ルは十分な精度でEを推定することができる。Eの実測値と計算値の回帰係数はr2=0.92である。さらに, ソルガム群落におけるEの実測値と計算値はほぼ一致し, 実測値と計算値の回帰係数はr2=0.63である。ソルガム群落におけるTの実測値と計算値はほぼ一致し, 回帰係数はr2=0.63である。ソルガム群落における蒸発散量(ET)の実測値と計算値はほぼ一致し, 実測値と計算値の回帰係数はr2=0.70である。従って, ENWATBALモデルは, E, TおよびETを十分な精度で推定することができると結論づける。抄録全体を表示PDF形式でダウンロード (939K) -
高谷 悟, 能登 正之1998 年 54 巻 3 号 p. 283-287
発行日: 1998/09/15
公開日: 2010/02/25
ジャーナル フリーPDF形式でダウンロード (544K)
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