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Volume 53, Issue 1
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Mayumi YOSHIMOTO, Yoshinobu HARAZONO, Walter C. Oechel1997 Volume 53 Issue 1 Pages 1-10
Published: March 10, 1997
Released on J-STAGE: February 25, 2010
JOURNAL FREE ACCESSThe characteristics of micrometeorology and the CO2 flux of the Arctic wet tundra ecosystem were measured during the mid-summer of 1994 at Prudhoe Bay, Alaska. CO2 flux was measured by the eddy correlation technique with a sonic anemometer and an open path IRGA.
Over the coastal Arctic tundra, the micrometeorology of the surface boundary layer changed remarkably according to wind direction. Wind from the Polar Sea brought cold and moist air, and southern wind brought warm and dry air with higher water vapor deficit, which resulted different CO2 flux over the wet tundra ecosystem.
A simple canopy resistance model was applied in order to analyze the relationship between the CO2 flux and the micrometeorology, in which parameters were determined using measured data. The ecosystem respiration increased with water temperature, and the rate was larger under higher wind speed. The photosynthesis rate decreased with water vapor deficit between leaves and the atmosphere, and its decrement was larger under higher wind speed conditions.
The effects of micrometeorology on the CO2 flux were examined using the model, which showed that the level of ecosystem respiration due to high water temperature and that of photosynthetic decrease due to high water vapor deficit were the same orders as the potential of photosynthesis measured over the coastal Arctic tundra at Prudhou Bay, Alaska in mid summer. The magnitude of the ecosystem respiration and the decrement of photosynthesis were large enough to diminish the downward CO2 flux to zero. The CO2 budget over the coastal Arctic wet tundra was much affected by the ecosystem respiration and the contribution of water stress to plant photosynthesis caused by higher temperature and drying.View full abstractDownload PDF (1474K) -
Hiromitsu KANNO1997 Volume 53 Issue 1 Pages 11-19
Published: March 10, 1997
Released on J-STAGE: February 25, 2010
JOURNAL FREE ACCESSDaily mean air temperatures during the occurrence of a Yamase wind were estimated on a 1km2 mesh by using a multiple-regression analysis.
By using the criteria presented by Kanno (1993), 397 occurrences of Yamase wind were distinguished from the other weather-condition days from 1979 to 1993.
Daily-mean air temperatures on the mesh were estimated in nearly the same way as was presented by the Japan Meteorological Agency (1988). At first, the topographical factors on each 1km2 mesh were made by using the digital national land information data. Also, the mean air temperature in each mesh was roughly calculated by using aerological observation data and added to the dependent values. Next, the equation for daily mean air temperature estimation was obtained by using a multiple regression analysis. After estimation of daily-mean air temperatures on each mesh, the residuals from observed temperatures were revised and added to the estimated data.
Days when a Yamase wind occurred in 1993 —a typical cool summer year in Japan—were selected as examples and the precision of the estimated value was examined. In the case of July 20, the coefficient squared (R2) was 0.92 and the standard error was 0.39°C, and therefore the estimation of temperature was highly precise. The estimated temperatures in this study (Yamase mesh temperatures) were compared with the traditional mesh temperatures obtained by using the normal-deviation method, The Yamase, mesh temperature is higher in the Pacific coastal area and lower inland. Also, the Yamase mesh temperature on the slope facing east in the Kitakami Valley was lower than the traditional mesh temperature. According to the analysis of temperature distributions on the east-west transection, the Yamase mesh temperature was more appropriate than the traditional mesh temperature. These estimated temperatures were also compared with the observed temperature data, and we found the estimated error of Yamase mesh temperature was smaller than that of the traditional one. As a result, the present method can estimate the mesh temperature more accurately than the traditional method.View full abstractDownload PDF (2297K) -
Kimio INOUE, Mayumi YOSHIMOTO, Hiroshi ABE1997 Volume 53 Issue 1 Pages 21-28
Published: March 10, 1997
Released on J-STAGE: February 25, 2010
JOURNAL FREE ACCESSThe Pacific side of Tohoku district has been frequently suffered from cool foggy easterly (Yamase) in summer times, resulting in severe decrease of rice production. The penetration of sea fog into inland area gives important effects on solar radiation impinging on crop fields.
This study was made to make clear cloud physical characteristics of sea fogs penetrated from the sea into the Taneichi region. The observations were made during the sea fog seasons from May to August in 1990 and 1991, respectively. The fog penetrates more frequently in periods of weak or no solar radiation, such as evening, night, and morning, than in daytimes. It was also observed that the sea fog into crop field is more frequent and strong under weather conditions with the wind directions from E to S.
The size distribution of sea fogs was measured by the Poval film method at the each observation point with different distances from the Taneichi seashore. The average size of sea fogs decreases linearly with the distance from the Taneichi seashore. This reason was mainly due to water evaporation on fog droplet surface. The results were compared with average size of sea fogs estimated indirectly from Eq. (2). Although there is relatively large scatter of points, it is reasonable to say that Eq. (2) can be used to estimate average values for droplet size from the data of visivility and fog water content.View full abstractDownload PDF (3427K) -
Md. Abdul BATEN, Hisashi KON1997 Volume 53 Issue 1 Pages 29-39
Published: March 10, 1997
Released on J-STAGE: February 25, 2010
JOURNAL FREE ACCESSField experiments were conducted on soybean (Glycin max L.) in summer and potato (Solanum tuberosum L.) in autumn to evaluate the effect of row orientations of crops on some selected micrometeorological factors during 1994 and 1995. The intercepted solar radiation was the largest in the plants growing in bidirection in summer and it exhibited intermediate trend in autumn as compared to E-W or N-S row orientations. In summer, penetrated solar radiation between two plants and near the stem base of a N-S row was larger than that of E-W row. While in autumn, the observed solar radiation between two plants and near the stem base of a E-W row was markedly larger than that of N-S row. The area weighted mean of penetrated solar radiation was larger in E-W soybean rows but lower in potato rows as compared to N-S row orientations. Soil surface temperature between N-S potato rows was larger than that of E-W potato rows and the upper canopy surface temperature of potato was larger in E-W rows as compared to N-S rows. Net radiation observed over E-W potato rows was larger as compared to N-S potato rows but net radiation measured under canopy of E-W potato rows was smaller than that of in N-S rows. Net radiation measured over N-S soybean rows was larger than that of E-W soybean rows and it was smaller between N-S soybean rows when measured under canopy as compared to E-W rows. The albedo observed over potato was larger over E-W rows as compared to N-S rows. Albedos over soybean canopy showed opposite trend with the albedos observed over potato canopy. It was larger over N-S rows as compared to E-W rows. High harvest index was associated with larger interception of radiation.View full abstractDownload PDF (1251K) -
Satoshi IWAKIRI1997 Volume 53 Issue 1 Pages 41-45
Published: March 10, 1997
Released on J-STAGE: February 25, 2010
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Taichi MAKI, Yoshinori SUZUKI, Seiji HAYAKAWA1997 Volume 53 Issue 1 Pages 47-53
Published: March 10, 1997
Released on J-STAGE: February 25, 2010
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1997 Volume 53 Issue 1 Pages 54a
Published: 1997
Released on J-STAGE: February 25, 2010
JOURNAL FREE ACCESSDownload PDF (42K) -
1997 Volume 53 Issue 1 Pages 54b
Published: 1997
Released on J-STAGE: February 25, 2010
JOURNAL FREE ACCESSDownload PDF (42K) -
Automation, Culture, and EnvironmentYasuomi IBARAKI, Tsuyoshi HONJO1997 Volume 53 Issue 1 Pages 55-58
Published: March 10, 1997
Released on J-STAGE: February 25, 2010
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The Executive Committee of Sectional Meeting on Lo1997 Volume 53 Issue 1 Pages 59-61
Published: March 10, 1997
Released on J-STAGE: February 25, 2010
JOURNAL FREE ACCESSDownload PDF (358K)
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