著者

菅野 洋光 小沢 聖

出版者

日本農業気象学会

雑誌

農業気象 (ISSN:00218588)

巻号頁・発行日

vol.55, no.4, pp.337-344, 1999-12-10 (Released:2010-02-25)

参考文献数

1

著者

福井 英一郎

出版者

The Society of Agricultural Meteorology of Japan

雑誌

農業気象 (ISSN:00218588)

巻号頁・発行日

vol.1, no.2, pp.145-152, 1944

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(1) 半旬期別平均値で調べると最寒期は日本の大部分の地方で第5期 (1月21日~25日) が之に相當し, 一部の地方 (裏日本西半部, 琉球, 臺灣) では稍々晩れて現はれるが之は此の前後に於ける雲量及降水量の最多期と一致する。最も高温なのは第45期 (8月9日~13日) に現はれる場合が最多く, 臺灣, 琉珠, 南九州, 甲信地方では之より早いが之も此前後を通じて雲量と降水量が最も少くなる時に當つてゐる。<br>(2) 寒の戻りは日本では第27半旬 (5月11日~15昭) に出現し, 此の場合は殆ど其時期が一致して場所によつての遲速が認められない。其原因として考へられるのは前線帯の通過で此時期に通過するものが最定時性を有つてゐる爲と考へられる。秋の殘暑は第58半旬 (10月13日~17日) に出現することが最も多いが氣温の上昇量は前の場合の低下量に比して可なり小さい。<br>(3) 氣温の昇降度を6半旬頃に區切つて求めて見ると春及秋に最大きな値を示す。之は前線や低氣壓の通過に基くものと考へられる。又其地理的分布は緯度及水陸配布の影響が最大きい。

著者

鈴木 義則 山本 薫

出版者

日本農業気象学会

雑誌

農業気象 (ISSN:00218588)

巻号頁・発行日

vol.41, no.1, pp.9-15, 1985-06-10 (Released:2010-02-25)

参考文献数

7

被引用文献数

1

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In the western parts of Japan, there are frequent risks of frost damage on several crops such as tea plants, vine and others in the late spring. Experimental studies on protection of plants from the cold by sprinkling method utilizing latent heat of solidification were carried out to make establish practical application methods for the sake of saving water consumption.The main purpose of the experiments is to find the lowest value of effective sprinkling intensity under several air temperature conditions. Through discussions on the fitness of spray catching ratio, the experimental results were examined with the theoretical values by Niemann's and by the author's.Some results found in the experiments at cold night with radiative cooling are summarized as follows:1) Temperature of iced leaf under sprinkling could not increase up to 0°C under both conditions of lower air temperatures and smaller sprinkling intensity. There were clearly critical point of sprinkling intensity, which could maintain leaf temperature around 0°C. These points which are defined as the lowest value of effective sprinkling intensity were also changed with surrounding air temperatures. They became larger as air temperatures became lower. The relations between them was a linear one (Fig. 3.). Having compared the measured values with the theoretical values in their tendencies in the graph, it was found that the Niemann's one differed from the actual one especially in the lower temperature range but the author's one agree well throughout the giving range of temperature.2) The spray catching ratio measured using grouped branches with leaves of cranberry tree (Viburnum awabuki K. Koch) showed almost constant values in the range from 0.1 to 4.6mm·hr-1 of sprinkling intensity and was about 0.29 on average (Fig. 4.). The theoretical values by Niemann's method changed from 0.27 (at O°C) to 0.36 (at -4°C). On the other hand, the author's one was 0.27 (0--4°C), which was more close value to the experimental one.3) The fall-off of leaf temperature after 20 minutes of sprinkling-off changed proportionally to the initial leaf temperature, when air temperatures were -3.0--5.8°C. They became larger as initial leaf temperature became higher (nearly equal to 0°C). These relations were also changed parallely with air temperatures, that is, the fall-off of leaves temperatures became large as lowering of air temperatures.4) After re-sprinkling, the iced leaf temperature which was lowered to around air temperature began to increase showing the shape of saturation curve. The larger the sprinkling intensity was, the shorter the required time to make plant body temperature 0°C was. But in the case of smaller intensity of sprinkling, the required time became longer exponentially.

著者

Keiko Kai Mikiko Kainuma Naomi Murakoshi Kenji Omasa

出版者

日本農業気象学会

雑誌

農業気象 (ISSN:00218588)

巻号頁・発行日

vol.48, no.5, pp.771-774, 1993 (Released:2010-03-16)

参考文献数

11

被引用文献数

4 8

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Strong correlations were found between blooming dates and meteorological factors. Based on these correlations, predictive maps of blooming dates in the Japanese Islands were proposed for each case of 1, 2 and 3°C of warming. The correlation was tested for the blooming dates of Prunus yedoensis, Prunus mume, Camellia japonica, Taraxacum, Rhododendron kaempferi, Wistaria floribunda, Lespedeza bicolor, Hydrangea macrophylla, Lagerstroemia indica, Miscanthus sinensis, etc., using the data of monthly mean temperatures, warming indices and cold indices from 102 meteorological stations in Japan between 1953-1990. Simple and multiple regression analyses were used for the correlation.Among meteorological factors, the strongest correlation was shown for monthly mean temperatures. Notably, the strongest was obtained for the case of Prunus yedoensis. The cold index and mean temperature of the previous December also showed the best correlation for species such as Prunus mume and Camellia japonica. Strong correlations between the leaf color-changing dates of Ginkgo biloba and Acer palmatum and the monthly mean temperature were found in one month of autumn. In these species, there was a delay of 2-7 days with a 1 degree increase in mean temperature.The 30-year 1km2 temperature-climate mesh-file developed by the Japan Meteorological Agency was used for the phenological estimation and predictive maps of blooming dates. Each observatory station was classified according to its annual mean temperature. Blooming for each mesh was estimated through monthly mean temperatures and regression equations of corresponding stations. Then, distribution maps of predictive blooming dates distinguished by 5-day divisions were made.

著者

庄野 浩資 天羽 弘一 高倉 直

出版者

日本農業気象学会

雑誌

農業気象 (ISSN:00218588)

巻号頁・発行日

vol.45, no.2, pp.87-92, 1989-09-10 (Released:2010-02-25)

参考文献数

7

被引用文献数

1 2

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A method to detect cucumber fruits in the canopy using image processing technique has been studied, with the aim of robotic harvesting. This method distinguishes a fruit from the other parts of the plant, not by the difference in their colors, but by the difference in shapes.The brightness in the digitized image was differentiated in horizontal direction, and clipped into three values (+, 0, -) by two thresholds. Then ridge-lines were drawn between (+) value area and (-) value area.The ridge-line images ordinarily contain some noise from the other parts of the plant. Accordingly, two images for the same scene were taken, one was illuminated from the left and the other was illuminated from the right. The center line image was obtained by comparing the two ridgeline images in consideration of the shift of the fruit's ridge-line which was calculated by a model. After the noise was reduced in the center line image, the center line of the fruit remained.This method contains four unknown parameters, and it was found that these parameters have the optimum value. But there were some deviations in the optimum values obtained from different images. The deviations were not so severe as to make the detection impossible in our experiment, but in general it is necessary to determine the optimum values applicable to many other scenes.This method was applied to some images taken in the field, and showed that it was able to detect the fruit when it was fully illuminated from both sides. The detection, however, became difficult when the light was intercepted by leaves and the illumination for the fruit was not enough.

著者

林 真紀夫

出版者

日本農業気象学会

雑誌

農業気象 (ISSN:00218588)

巻号頁・発行日

vol.40, no.3, pp.289-292, 1984-12-10 (Released:2010-02-25)

参考文献数

9

著者

ショウ ロバートエッチ

出版者

日本農業気象学会

雑誌

農業気象 (ISSN:00218588)

巻号頁・発行日

vol.38, no.3, pp.339-342, 1982-12-10 (Released:2010-02-25)

著者

Shin NAGAI Shinpei YOSHITAKE Tomoharu INOUE Rikie SUZUKI Hiroyuki MURAOKA Kenlo Nishida NASAHARA Taku M SAITOH

出版者

日本農業気象学会

雑誌

農業気象 (ISSN:00218588)

巻号頁・発行日

vol.70, no.3, pp.163-170, 2014 (Released:2014-09-10)

参考文献数

26

被引用文献数

6 10

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Long-term continuous phenological observation of cherry tree blooming is an important and challenging task in the evaluation of year-to-year weather and climate changes in spring in Japan. Here, (1) we performed daily field observations with a time-lapse digital camera in a deciduous broad-leaved forest in Japan from January 2004 to December 2013; and (2) we detected year-to-year variations in the blooming phenology of Prunus sargentii by visual inspection of the images and by image analysis. We found that (1) the red digital numbers (i.e., the digital intensity values of the red pixels; DNR) extracted from the time-lapse digital camera images tended to peak in full bloom; and (2) the green excess index (GEI) (based on the red, green, and blue digital numbers) tended to be lowest in full bloom. These results indicate that DNR and GEI are useful for detecting the timing of full bloom in P. sargentii.

著者

中川 行夫

出版者

日本農業気象学会

雑誌

農業気象 (ISSN:00218588)

巻号頁・発行日

vol.29, no.2, pp.121-122, 1973-09-30 (Released:2010-02-25)

著者

斎藤 隆幸

出版者

日本農業気象学会

雑誌

農業気象 (ISSN:00218588)

巻号頁・発行日

vol.23, no.2, pp.65-74, 1967-09-30 (Released:2010-02-25)

参考文献数

9

被引用文献数

1 4

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In order to study the nocturnal cooling of plant communities, the fall of temperature of a wheat field during night was calculated for various values of net radiation and of wind speed above the surface of the wheat field, 60cm height and with 4.4 of L A I. The results of the calulation were compared with the fall of temperature of the bare soil surface during night.As it is observed that the thermal condition of the plant layer is approximately in equilibrium for the time just before sunrise, the vertical distribution of leaf temperatue, air temperature and water vapour density within the plant layer at the time of sunrise are calculated with various values of net radiation and of wind speed at the height 40cm above the surface of the wheat field on the assumption of equilibrium condition.The calculated profiles of leaf temperature and air temperature for 0.10cal·cm-2·min-1 of net radiation are shown in Fig. 4 for the values of 0.5m·sec-1 and 3.0m·sec-1 of wind speed. It is seen from Fig. 4 that difference between the temperatues of the upper part of plant layer and of soil surface under the plant layer is about 9.0°C for 0.5m·sec-1 of wind speed and about 0.5°C for 3.0m·sec-1.The fall of temperature during night was obtained from the difference between the calculated value of temperature and the temperature at the time of sunset. The temperature at the time of sunset was assumed to be equal to that at the top of the inversion layers. The fall of leaf temperature of the upper part of the wheat field, shown in Fig. 3, is in very close agreement with observational values. As seen in Fig. 3, the temperature fall increases rapidly with decreasing the wind speed below 1m/sec.The fall of temperature of the bare soil surface was also calculated for the radiation values and the wind speed at the height 50cm above the soil surface. The calculated results of the fall are in good agreement with those of BERLYAND (1956). The variation in the fall of temperature of the bare soil surface with wind speed is not so apparent as in the case of the wheat field.By use of both calculated results of the wheat field and of the bare soil surface, comparison was made of the fall of temperature of the upper part of the wheat field and of the bare soil surface under the same meteorological conditions. From the results it can be inferred that the night minimum temperature of the upper part of the wheat field is lower than that of the bare soil surface for the condition of calm wind, but that for windy condition the reverse is the case.

著者

林 陽生

出版者

日本農業気象学会

雑誌

農業気象 (ISSN:00218588)

巻号頁・発行日

vol.48, no.1, pp.57-64, 1992-06-10 (Released:2010-02-25)

参考文献数

15

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To investigate dependencies in the magnitudes of a waving ear on mean wind speed, field observations were carried out over a barley filed in the ripe stage. Fluctuating displacements derived from HONAMI were measured using a newly designed 2-dimension strain sensor. The velocity fields were measured by a sonic anemometer-thermometer.A coherently waving phenomena of HONAMI appeared and was evaluated by the fluctuating displacements of a single ear of the stand. Dividing a time series of the fluctuating displacement into five typical bands of frequency by use of an analog filter, it was shown that there are two dominants of 0.5-Hz and below 0.1-Hz in the original. The bands were from a natural frequency and a gustness of wind respectively. Comparing the amplitudes, the natural frequency contributed remakably to the original fluctuation of HONAMI.Magnitudes of an instantaneous ear-displacement, which represents 0.5-0.6-Hz of frequency, varied with increments of the mean wind speed within a range of 2.6-4.4-m/s. Except for this range, the dependency between the amplitude and the wind speed was not clear.Instantaneous changes in lateral displacements and velocity fluctuations were quite similar except for the component of higher frequencies. Under such circumstances, an ear-displacement will appear to infulence strongly the aero-dynamical properties of the canopy boundary layer.The force per unit length acts on a waving ear generates by a relative velocity of u-dx/dt. Here, u is the mean wind speed, and dx is the displacement of an ear from its mean position during dt. Using this concept, drug force was evaluated under two criteria for leeward ear-moving and ear-standing. Under the windy conditions, the force loaded on an waving ear reduced by 10% against the standing criterion with dx=0. On the other hand, the reduction rate became small down to 4% of the standing criterion under the condition of weak wind.

著者

Toshichika Iizumi Gen Sakurai Masayuki Yokozawa

出版者

日本農業気象学会

雑誌

農業気象 (ISSN:00218588)

巻号頁・発行日

pp.D-13-00023, (Released:2014-04-03)

参考文献数

42

被引用文献数

3 10

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The consequences of observed changes in climate and management on yield trends in major crop-producing regions have implications for future food availability and access. We presents an assessment of the impacts of historical changes in sowing date and climate to the maize yield trend in the United States (U.S.) Corn Belt from 1980 to 2006, using large-area crop modeling and data assimilation technique (the model optimization based on the Markov Chain Monte Carlo method). The model calibrated at a regional scale successfully captured the major characteristics of the reported changes in yield and the timing and length of maize growth periods over the Corn Belt. The simulation results using the calibrated model indicate that while the climate change observed for that period likely contributed to decrease the yield trend, the positive contribution from the reported earlier shift of sowing date offset the negative impacts. With given spread in the assessment results across previous studies and this study, the credence of the conclusion that the negative impacts of the climate change on the U.S. maize yield trend are more likely attributed to the decreasing growing-season precipitation trend than to the temperature trend increased. This study addressed an emerging use of large-area crop modeling and data assimilation to attribute observed change in crop yield trend to climate and management.

著者

丸岡 知浩 伊藤 久徳

出版者

養賢堂

雑誌

農業気象 (ISSN:00218588)

巻号頁・発行日

vol.65, no.3, pp.283-296, 2009-09-10

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植物の開花や落葉などの時期は、気温に密接に関連している。従ってこれらは地球温暖化の影響を受けやすいと言える。実際、Walther et al.は近年の気温上昇の影響を受けて、植物の開花や落葉などの時期が変化していることを報告した。一般的には温暖化とともに、開花は早くなり、落葉は遅くなる。しかし暖地では冬季に十分な寒さを経なくなるので、休眠打破が遅れ、開花が遅くなることも指摘されている。日本のサクラも例外ではない。近年の気温上昇傾向を受けて、サクラの開花の時期は早くなっている。しかし冬季に暖かいと休眠打破が遅れ、開花が遅くなることも知られている。その典型が2007年であった。この年は暖冬で、全体的には開花日が早まったが、南九州や八丈島などの暖地で極端に開花が遅くなる現象が見られた。特に八丈島では観測史上初めて満開には至らなかった。本研究では、DTS(温度変換日数)法に基づきながらも、全国一律のパラメータを用い、予測したい期間の気温のみで休眠打破の時期、開花日までを予測できるように開花モデルを作成する。また、さらに現在気候において開花しない名瀬と開花の南限である種子島のデータを使用することによって、開花そのものの有無の判定基準を作成する。そしてその開花モデルを将来の予測気温に適用し、将来の開花を予測する。

著者

佐々木 喜一 木村 玲二 伊志嶺 正人 大田 守也

出版者

日本農業気象学会

雑誌

農業気象 (ISSN:00218588)

巻号頁・発行日

vol.61, no.1, pp.77-81, 2005 (Released:2006-07-21)

参考文献数

7

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Evapotranspiration from a sugar cane field was observed during the summer season in the Miyako Islands. Interpolation was also conducted for the data deficit period by using the bulk transfer coefficient and evapotranspiration efficiency, which were represented as a function of solar radiation and soil water content. Evapotranspiration was 6.4 mm day-1 in late June, and decreased gradually. It was under 3.5 mm day-1 (100 W m-2) at the end of October.

著者

真木 太一

出版者

日本農業気象学会

雑誌

農業気象 (ISSN:00218588)

巻号頁・発行日

vol.39, no.3, pp.225-234, 1983-12-10 (Released:2010-02-25)

参考文献数

3

著者

中山 敬一 浦野 永久 今 久 松岡 延浩

出版者

日本農業気象学会

雑誌

農業気象 (ISSN:00218588)

巻号頁・発行日

vol.48, no.4, pp.359-363, 1993-03-10 (Released:2010-02-25)

参考文献数

5

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To clarify the effects of water blooms on the heat balance in a water body, some heat balance components were observed in a small water pond (length and breadth of 160cm; depth of 45cm) made of polystyrene board of 15cm thick.Floatage of stratified water blooms increased the albedo on the water surface but decreased the net radiation in daytime. The water temperature near the surface was increased in daytime, and decreased in nighttime as a result of the floatage of water blooms. The amount of heat storage in the water body was reduced by the stratified water blooms, because of suppressing effect for transmission of solar radiation into the water body. The amount of latent heat flux was increased in daytime by the stratified water blooms but decreased in nighttime depending on the lower water surface temperature and the reduced heat storage in the water body.

著者

武田 知己 平野 高司 浦野 慎一 堀口 郁夫

出版者

The Society of Agricultural Meteorology of Japan

雑誌

農業気象 (ISSN:00218588)

巻号頁・発行日

vol.57, no.3, pp.145-153, 2001-09-10 (Released:2010-02-25)

参考文献数

14

被引用文献数

1 1

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Canopy structure of crops is an important factor determining the radiation environment of the canopy. Although many researchers have dealt with foliage distribution by using a probability density function, studies that reproduce a spatial destribution and spatial form of foliage in 3 dimensional (3D) space have only recently been reported. In this study, we developed a geometric model by using L-system to reproduce the form of sunflower plants in 3D space. The model consisits of frame and leaf models. In order to obtain functions to illustrate the frame model, positions of nodes, leaf bases, and leaf tips were measured from photographs of sunflower plants taken at five different stages in a growing season, and lengths of internode, petiole and leaf were determined. Moreover, lengths of five lateral veins, and divergence angle between midrib and fifth lateral vein were measured.Growth curve of internode and petiole could be expressed as a logistic function of step number in L-system. Leaves elongated as a function of petiole length. Zenith angle of petiole decreased with step number from 1 to 7, and then stabilized at about 35°. Leaf zenith angle was related to petiole zenith angle. Divergence angles between successive leaves differed in different phyllotaxis. In distichous phyllotaxis, divergence angle was 180° between the leaves at the same node, and 90° between the leaves at successive nodes. On the other hand, in alternate phyllotaxis, divergence angle was about 135°. Leaf expansion could be related to increase in leaf length.In conclusion, the geometric model using L-system successfully reproduced the growth of sunflower plants with increase in node number.

著者

日下部 正雄

出版者

日本農業気象学会

雑誌

農業気象 (ISSN:00218588)

巻号頁・発行日

vol.16, no.1, pp.34-37, 1960-06-30 (Released:2010-02-25)

参考文献数

3

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著者は主として西日本災異誌によつて梅雨によつて起つたと推定される災害について調査した。まず梅雨による災害が全災害のうちでどのような位置を占めるかをみると, 古代においては干ばつが首位を占め梅雨についての記録が比較的少なかつたが, 14世紀ごろから次第に重要性を増し, 17世紀ごろになると梅雨は台風についで注目すべき位置を占めるようになつている。またこのころになると単なる長雨による災害ではなく, 梅雨末期の大雨が大きな役割を演ずることを, 洪水の旬別ひん度や, 川潮の旬別ひん度などから明らかにした。また山潮が風化花崗岩土地帯に多いことを示した。

著者

石川 大太郎 湯田 健之 関岡 信一 肥山 浩樹 石黒 悦爾

出版者

養賢堂

雑誌

農業気象 (ISSN:00218588)

巻号頁・発行日

vol.64, no.2, pp.61-68, 2008-06-10

被引用文献数

2 1

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近年、地球温暖化等の環境変動により局地的な豪雨が頻発している。鹿児島県においても北部地域で2003年7月20日ならびに2006年7月22日に日雨量350mmを超える記録的な大雨が発生した。これらの局地的豪雨は大規模な斜面崩壊・大小の河川の氾濫などを誘発し、多大の被害や損害をもたらしている。本研究では、斜面崩壊地域予測を目的として、土壌水分の変動を植生の葉内水分変動を用いて簡易に推定する手法の開発を試みた。室内において樹木から摘採した葉の含水率変動と分光反射特性を解析し、衛星データ(現在一般的に用いられており汎用性が高いと考えられるLandsat/TMを対象)、ならびに近赤外域を有しない航空写真について、含水率を推定する指標を考案した。さらに、これらのデータが得られない場合の対応として、簡易にしかも即時的に取得可能な分光画像に対応した分光反射特性を用いた指標の考案を試みた。またこれらの指標を適用した含水率変動率指標(WCF)を提案し、現地調査にて撮影した分光画像及び対象地域を撮影した航空写真を用いて本研究の実用性を検討した。