農業気象
Online ISSN : 1881-0136
Print ISSN : 0021-8588
ISSN-L : 0021-8588
43 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
  • 松田 松二, 只木 良也, 出原 茂樹, 宅見 啓, 大島 康行
    1987 年 43 巻 1 号 p. 3-13
    発行日: 1987/06/10
    公開日: 2010/02/25
    ジャーナル フリー
    長野県における代表的な人工林である落葉松林の物理環境の季節変化を, 森林の環境影響評価を念頭におきながら測定した。
    この季節変化は着葉の状態と密接に関係している。すなわち, アルベドの最高値は黄葉を反映して十月下旬に18%を示し, 樹冠透過放射量の最高値は落葉した冬期に約45%となった。樹冠はこのように熱の観点からすれば, 林床に対してマルチの役割を果たしており, 結果として林床の土壌表面温度は裸地区のそれよりも, 盛夏において, 最高温で約30℃, 最低温で約3℃低下して振幅も減衰している。林内の気温はまた盛夏において裸地区のそれより7.5℃低下している。太陽エネルギーの主な吸収部分は開葉, 落葉の過程に従って垂直方向に移動し, これは林内の気温垂直分布の季節変化に反映されている。熱収支の結果によれば, 最も大きな森林影響の一つは潜熱フラックスによる熱輸送で, 落葉松林はボーエン比を調節することによって, 周辺へ冷涼な大気を送り出していることになる。このような熱交換は裸地や都市域のアスファルト及びコンクリート面では殆ど欠如していることが強調されるべきである。
  • 1987 年 43 巻 1 号 p. 14
    発行日: 1987/06/10
    公開日: 2010/02/25
    ジャーナル フリー
  • 河野 徳義
    1987 年 43 巻 1 号 p. 15-20
    発行日: 1987/06/10
    公開日: 2010/02/25
    ジャーナル フリー
    This paper describes climatic factors in the greenhouses ventilated with two different systems; forced ventilation and natural roof ventilation. The author discusses 1) the profile of inside air temperature related to that of solar radiation, 2) horizontal distribution of inside air flow velocity and carbon dioxide concentration, and 3) photosynthetic rate of a tomato crop.
    Air temperature varied according to the height from the floor surface. Since the amount of solar radiation at the lower part in the plant canopy was smaller than that at the upper part, the air temperature decreased at the lower part. This decrease in temperature became larger with the increase in LAI. In the naturally ventilated greenhouse, a low temperature spot was observed close to the roof ventilators, through which the outside air came into the inside. The temperature in the spot was lower than that at the same position in the greenhouse ventilated with fans.
    Horizontal patterns of inside air flow velocity was similar to those of carbon dioxide concentration. The air flow velocity was large at the early stage of crops, but was reduced at the later stage in the naturally ventilated greenhouse. In the fan ventilated greenhouse, the incoming air descended to the floor surface at the early stage of crops, and thus carbon dioxide was supplied to the crops. As the crop stage became later, the area with large air flow velocity expanded in the whole greenhouse. Under such a condition a clear decline of carbon dioxide was observed from the inlet to the outlet of the air.
    The author estimated the reduction of photosynthetic rate due to the drop in carbon dioxide concentration. The percent reduction was 7-15% (LAI=1.0) and 22-32% (LAI=3.5) in the naturally ventilated greenhouse; about 10% (LAI=1.0) and about 25% (LAI=3.5) in the fan ventilated greenhouse.
  • (3) 培養小植物体を含む閉栓容器内の炭酸ガス濃度測定と培養小植物体の純光合成速度の推定
    富士原 和宏, 古在 豊樹, 渡部 一郎
    1987 年 43 巻 1 号 p. 21-30
    発行日: 1987/06/10
    公開日: 2010/02/25
    ジャーナル フリー
    This paper describes the CO2 concentration in tissue culture vessels and the net photosynthetic rates of tissue cultured plantlets in the closed vessels with stopper.
    Firstly, this paper shows changes with passage of time in CO2 concentration in the closed vessels containing plantlet (s) cultured under usual conditions. Secondly, it gives the estimated net photosynthetic rates of plantlets cultured in the closed vessels. Lastly, it estimates the effects of CO2 enrichments on the photosynthetic rate of one of the plantlets used.
    The plantlets used were 8 genera of ornamental foliage, and had grown large enough to pot. The CO2 concentration was measured by using a gas chromatograph.
    In order to estimate the photosynthetic rates of the plantlets in the closed vessels, a model of CO2-net photosynthesis was developed, and the parameters of the model were estimated on the basis of the measured values of the CO2 concentration in the closed vessels.
    The model is given by the following equation:
    Pn=Pns⋅[1-exp {-G/Pns⋅(Kc-C)}]
    where Pn is the net photosynthetic rate [μcm3 CO2 mg-1 h-1], Pns the saturated net photosynthetic rate for CO2 concentration [μcm3 CO2 mg-1 h-1], G the gradient of CO2-net photosynthesis curve at CO2 compensation concentration [μcm3 CO2 mg-1 h-1 vpm-1], Kc the CO2 concentration in the closed vessel [vpm], and C the CO2 compensation concentration [vpm]. Pns, G and C are the parameters of this model.
    The results can be summarized as follows:
    (1) In all closed vessels, the CO2 respired in the dark period was accumulated to the concentration level from about 3000 to 9000vpm. One or two hours after the start of the light period, the CO2 concentration in the vessels are rapidly decreased to less than 90vpm by the photosynthesis of plantlets. Thus, it became clear that all plantlets have photosynthetic ability under the light period.
    (2) The plantlets could not fully achieve their photosynthetic capacity, because the CO2 concentration in the closed vessels were too low in most of the light period.
    (3) Estimated net CO2 uptake per day of all plantlets in the closed vessels were negative. This means that the plantlets had grown by using sucrose in the media as the main source of carbonhydrate.
    (4) The results of the estimation on the effects of CO2 enrichment indicate that net photo-synthetic rate of a plantlet may be increased not only by increasing the inside CO2 concentration, but also by increasing the outside concentration or by increasing the number of air changes of the vessel when the outside concentration is higher than that of inside during the light period.
    The above results indicate that tissue cultured plantlets in the closed vessels can be grown photoautotrophically during and after the multiplication stage by improving the CO2 and light environments in the closed vessels.
  • (2) リモートセンシングによる緑地の抽出と表面温度の解析
    本條 毅, 高倉 直
    1987 年 43 巻 1 号 p. 31-36
    発行日: 1987/06/10
    公開日: 2010/02/25
    ジャーナル フリー
    Remote sensing is perhaps the most economical method for assessing the thermal effects of urban greenspaces. Since 1984 the thermal infrared band of Landsat TM sensor provides high resolution imagery data showing surface temperature distributions. In previous studies we showed Landsat TM data clearly exhibit characteristics of lower temperature in the urban greenspaces and investigated the intensity of temperature decrease in urban greenspaces by comparing the distribution of temperature with the distribution of greenspaces classified by using remote sensing data.
    However as the scale of the urban components is usually smaller than the resolution of Landsat TM sensor (30m×30m), many pixels contain a mixture of cover classes. A pixel including multiple classes is called a mixel and it is very hard to classify mixels with conventional methods such as the maximum likelihood method or the cluster analysis. Therefore, the precision of the classification is restricted by the resolution of a pixel.
    In the present study we introduce fuzzy clustering to examine the distribution of urban greenspaces more precisely. Fuzzy clustering is based on the theory of fuzzy sets which allows fuzzy boundary of sets. Using this method it is possible to calculate the ratio of greenspaces in a mixel (hereafter we call the ratio ‘greenness’). The distribution of greenspaces as the result of fuzzy clustering is compared with the temperature distribution.
    As a test area, a region of 32×32 pixels in Minato-ward, Tokyo is selected from Landsat TM data of Kanto district (pass 107-row 35, acquired on Aug. 3rd, 1985). The ground truth of the greenness is calculated from the vegetation map of Minato-ward digitized by an image scanner.
    To evaluate the precision of fuzzy clustering we compared the ground truth of greenspaces shown in Fig. 5(a) with the result of fuzzy clustering shown in Fig. 5(b). These patterns visibly show good agreement but the greenness of a corresponding pixel is not exactly the same because of various types of errors. After the process of flattening to ease the errors, the relation between the ground truth and the result of fuzzy clustering is shown in Fig. 6. The agreement is satisfactory considering the various errors included in the original data and difficulty of the classification.
    To show the relation between the ratio of greenspaces and surface temperature, the distribution of surface temperature obtained from band 6 is also shown in Fig. 5(c). It seems that low temperature area generally coincides with the high greenness area.
  • 小田 雅行, 野中 正義, 星野 和生
    1987 年 43 巻 1 号 p. 37-39
    発行日: 1987/06/10
    公開日: 2010/02/25
    ジャーナル フリー
  • 金関 四郎
    1987 年 43 巻 1 号 p. 40
    発行日: 1987/06/10
    公開日: 2010/02/25
    ジャーナル フリー
  • 清野 豁, 元田 雄四郎
    1987 年 43 巻 1 号 p. 41-44
    発行日: 1987/06/10
    公開日: 2010/02/25
    ジャーナル フリー
  • 朱 超群, 鳥谷 均, 古藤田 一雄, 吉野 正敏
    1987 年 43 巻 1 号 p. 45-51
    発行日: 1987/06/10
    公開日: 2010/02/25
    ジャーナル フリー
  • 久保木 光熙
    1987 年 43 巻 1 号 p. 53-57
    発行日: 1987/06/10
    公開日: 2010/02/25
    ジャーナル フリー
  • 本條 毅, 庄野 浩資, 平藤 雅之, 佐瀬 勘紀
    1987 年 43 巻 1 号 p. 59-64
    発行日: 1987/06/10
    公開日: 2010/02/25
    ジャーナル フリー
  • 高橋 英紀, 真木 太一
    1987 年 43 巻 1 号 p. 65-70
    発行日: 1987/06/10
    公開日: 2010/02/25
    ジャーナル フリー
  • 農業気象災害研究部会・近畿・中国四国・九州支部
    1987 年 43 巻 1 号 p. 71-75
    発行日: 1987/06/10
    公開日: 2010/02/25
    ジャーナル フリー
  • 施設園芸研究部会・情報システム研究部会
    1987 年 43 巻 1 号 p. 77-78
    発行日: 1987/06/10
    公開日: 2010/02/25
    ジャーナル フリー
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