Journal of Agricultural Meteorology

Why the Thickness of the Dry Surface Layer in Sand Dune Fields Exhibits a Diurnal Variation?

Tetsuo KOBAYASHI, Akiyoshi MATSUDA, Makio KAMICHIKA, Yoshihiro YAMAMUR ...

1991 Volume 47 Issue 1 Pages 3-9
Published: June 10, 1991
Released on J-STAGE: February 25, 2010

DOIhttps://doi.org/10.2480/agrmet.47.3

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A dry surface layer usually forms in a sand dune field and it has an effect on the micro-climate. The thickness of the layer exhibits a diurnal variation with a maximum in the late afternoon and a minimum in the early morning. The thickness is a measure of the degree of dryness in the upper layers in sand dune fields; thus, the diurnal variation in the thickness suggests that there are large diurnal as well as irregular variations in the moisture conditions of the upper layers. The reason for the diurnal variation is that the rate of evaporation from the ground changes during the course of the day, while the upward water flux in the moist underlayer remains nearly constant throughout the day.

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Effects of Cultural Temperatures on the Ice Nucleation Activities of INA Pseudomonas syringae

Zhimin LIU, Michiaki OKANO, Keiichi NAKAYAMA, Juro HANYU, Hisashi KON, ...

1991 Volume 47 Issue 1 Pages 11-14
Published: June 10, 1991
Released on J-STAGE: February 25, 2010

DOIhttps://doi.org/10.2480/agrmet.47.11

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The study was conducted to clarify the effects of cultural temperature on the activities of INA (ice nucleation-active) bacteria Pseudomonas syringae.
INA bacteria were cuttured at 5 levels of temperature (0, 10, 20, 25 and 30°C) for 1 to 5 days of cultural periods respectively. The soybean leaflets contacted with the suspension of these INA bacteria cultured under above cultural conditions. The ice nucleation activities were evaluated through the freezing temperatures of water droplets suspended with INA bacteria and of soybean leaflets spread with INA bacterial suspension.
There were no large differences between the freezing temperatures of water droplets suspended with INA bacteria cultured under the temperature condition of 20°C and below. However, the freezing temperatures of droplets suspended with INA bacteria cultured at 25 and 30°C decreased with the cultural duration.
On the other hand, the freezing temperatures of soybean leaflets also dependent on cultural temperature, although they were generally lower than those of water droplets. The ice nucleation activities of the INA bacteria cultured under 25 and 30°C were almost nil.

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An Estimation of Leaf Area Damaged by Leaf Eater Using Spectral Reflectivity

Haruhiko YAMAMOTO, Kazushige SOGAWA, Tomonari WATANABE, Hiroya HIGUCHI

1991 Volume 47 Issue 1 Pages 15-20
Published: June 10, 1991
Released on J-STAGE: February 25, 2010

DOIhttps://doi.org/10.2480/agrmet.47.15

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For estimating the percentage of damaged leaf areas of rice and soybean single leaves infested respectively with Cnaphalocrocis medinalis and Spodoptera litura of leaf eater, non-destructive measuring method was investigated using spectro radiometer.
1) The most effective index of spectral reflection parameter for estimating the percentage of rice leaf area eaten by Cnaphalocrocis medinalis was (R_750nm-R_450nm)/(R_750nm+R_450nm). The regression equation was the percentage of damaged leaf areas=144.5-180.5 (R_750nm-R_450nm) /(R_750nm+R_450nm). The correlation coefficient was -0.971.
2) The most effective index of spectral reflection parameter for estimating the percentage of soybean leaf area eaten by Spodoptera litura was (R_750nm-R_600nm)/(R_750nm+R_600nm). The regression equation was the percentage of damaged leaf areas=119.0-166.0 (R_750nm-R_600nm)/(R_750nm+R_600nm). The correlation coefficient was -0.983.
3) The observed and the estimated values of damaged leaf percentage areas were distributed on the ratio line of one to one. The correlation coefficient for rice and soybean leaves infested with Cnaphalocrocis medinalis and Spodoptera litura were 0.981 and 0.966, respectively.

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Japanese Weather Highlights in 1990

Osamu KITAMURA

1991 Volume 47 Issue 1 Pages 21-27
Published: June 10, 1991
Released on J-STAGE: February 25, 2010

DOIhttps://doi.org/10.2480/agrmet.47.21

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Micrometeorological Characteristics of the Sloping Greenhouse at Kuroki, Fukuoka Prefecture

Haruhiko YAMAMOTO, Hiroshi SEINO, Hitoshi HONJO

1991 Volume 47 Issue 1 Pages 29-34
Published: June 10, 1991
Released on J-STAGE: February 25, 2010

DOIhttps://doi.org/10.2480/agrmet.47.29

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Cool Summer Damage and Kenji MIYAZAWA

Agrometeorological Consideration on “the Life Story of Gusukô Budori”

Takeharu BOKURA

1991 Volume 47 Issue 1 Pages 35-41
Published: June 10, 1991
Released on J-STAGE: February 25, 2010

DOIhttps://doi.org/10.2480/agrmet.47.35

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The Study of Water and Carbon Dioxide Circulation over Semi-Arid Fields in China

Eiji OHTAKI, Osamu TSUKAMOTO, Takeshi MIURA

1991 Volume 47 Issue 1 Pages 43-46
Published: June 10, 1991
Released on J-STAGE: February 25, 2010

DOIhttps://doi.org/10.2480/agrmet.47.43

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Symposium on Fruit Quality and Light

Working Group on Meteorological Improvement Studie

1991 Volume 47 Issue 1 Pages 47-50
Published: June 10, 1991
Released on J-STAGE: February 25, 2010

DOIhttps://doi.org/10.2480/agrmet.47.47

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Erratum to : A Report on the Establishment Meeting of the Heilongjiang Society of China-Japanese Agricultural Meteorology

1991 Volume 47 Issue 1 Pages 81a
Published: 1991
Released on J-STAGE: February 25, 2010

DOIhttps://doi.org/10.2480/agrmet.47.81a

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Erratum to : Estimation of Surface Soil Water Content in Kyushu by Spectral Characteristics

1991 Volume 47 Issue 1 Pages 81b
Published: 1991
Released on J-STAGE: February 25, 2010

DOIhttps://doi.org/10.2480/agrmet.47.81b

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