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REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
> Journal Vol & Issue
Korean Journal of Agricultural and Forest Meteorology
Journal Basic Information
Journal DOI :
Korean Society of Agricultural and Forest Meteorology
Editor in Chief :
Volume & Issues
Volume 2, Issue 4 - Dec 2000
Volume 2, Issue 3 - Sep 2000
Volume 2, Issue 2 - Jun 2000
Volume 2, Issue 1 - Mar 2000
Selecting the target year
Changes in Absorption Coefficient of Krypton Hygrometer in Long-term Monitoring of Evapotranspiration and Its Calibration Using a Dew Point Generator
Park Yunho ; Kim Joon ; Lee Heechoon ; Lim Jonghwan ; Kwon Wontae ;
Korean Journal of Agricultural and Forest Meteorology, volume 2, issue 3, 2000, Pages 75~79
Calibrations of fast-response krypton hygrometers were carried out using a dew-point hygrometer to investigate the changes in their absorption coefficients due to long-term field operation. Absorption coefficients changed proportionally with the number of hours of field operation. The increase in absorption coefficient indicates that the water vapor flux, calculated with the original absorption coefficient, would underestimate the true flux in the field. To minimize the uncertainty in quantifying evapotranspiration and surface energy budget studies, frequent calibrations (for example, every 1500 hours of field operation) of krypton hygrometer are recommended.
On the Effect of Tube Attenuation on Measuring Water Vapor Flux Using a Closed-path Hygrometer
Hong Jinkyu ; Kim Joon ; Choi Taejin ; Yun Jin-il ; Tanner Bert ;
Korean Journal of Agricultural and Forest Meteorology, volume 2, issue 3, 2000, Pages 80~86
Eddy covariance method is widely used in measuring vertical fluxes of mass and energy between the atmosphere and the biosphere. In this method, scalar concentration is measured with either open-path or closed-path sensors. For the latter, fluctuations of scalar concentration are attenuated as the sample travels through a long tube, resulting in flux loss. To quantify this tube attenuation, water vapor concentrations measured with both closed-path and open-path sensors were analyzed. Our statistical analysis showed that the power spectral density obtained from the closed-path sensor was different from that from the open-path sensor in the frequency range of > 0.5 Hz. The loss of water vapor flux due to tube attenuation was < 5% during midday. At nighttime, however, the flux loss increased significantly because of the low wind speeds and the weak turbulence sources. Theoretical calculation for the tube attenuation showed a small bias in high frequency range probably because of the interaction of sticky water vapor with a tube wall.
Microclimate in Rice Nursery Bed Covered with Various Materials
Hwang Kyu Hong ; Lee Jeong Taek ; Yun Jin Il ; Shim Kyo Moon ; Hur Seung Oh ;
Korean Journal of Agricultural and Forest Meteorology, volume 2, issue 3, 2000, Pages 87~94
To recommend adequate covering materials and shapes of rice nursery bed for mechanical transplanting rice seedling, measuring of microclimate inside the rice nursery protected by polyethylene tunnel type, polyester tunnel type, and polyester flat type was compared to that outside the nursery. The vapor pressure deficit inside the polyester tunnel and polyethylene tunnel was higher than that outside the tunnel during daytime on a sunny day. During daytime on cloudy with rain day, the vapor pressure deficit inside polyester tunnel was higher than that in polyethylene tunnel or outside the nursery tunnel. The heat fluxes in the rice nursery tunnel during daytime flowed more to the soil than to the outside tunnel. Amounts of soil heat fluxes in polyethylene tunnel were higher than in polyester flat and polyester tunnel. The vertical profile of air temperature inside the nursery tunnel came to inversion during daytime and was lapse during nighttime regardless weather condition. The maximum temperature inside the nursery tunnel were 47.2
in polyethylene tunnel and 37.
in polyester tunnel which was 21.1
higher than outside the tunnels respectively on sunny day. On cloudy with rain day, the temperature inside nursery tunnel was higher 8.4
polyethylene and polyester tunnel respectively then outside. Daily temperature changes became larger in the polyethylene tunnel, polyester tunnel, and outside the nursery tunnel in order. The rice seedling growth in polyester tunnel was better than the other nursery beds.
Analysis of Meteorological Variation during Winter Barley Cropping Season in Korea
Shim Kyo-Moon ; Lee Jeong- Taek ; Yun Seong-Ho ; Hwang Kyu-Hong ;
Korean Journal of Agricultural and Forest Meteorology, volume 2, issue 3, 2000, Pages 95~102
The northward shift of the cultivation region of winter barley has been considered because of consecutive warm winters from the middle of 1980's. There was 1.02
rise in mean air temperature during winter barley cropping season from 1975 to 1998. During this period, the maximum air temperature affected the mean air temperature rise rather than the minimum air temperature. The amount of mean precipitation was 513.3 mm during winter barley cropping season from 1975 to 1998 and was least in 1992. Sunshine hours has increased little by little in the all regions except rural regions. The air temperature during winter barley cropping season from 1987 to 1999 in which the winter was warm was higher than the normal air temperature(1961~1990). On the other hand, the air temperature during winter barley cropping season from 1974 through 1986 was similar to the normal air temperature. The amount of mean precipitation during winter barley cropping season from 1987 through 1999 was similar to the normal precipitation except April. During this period, the amount of mean precipitation of April was lower by 26 mm than the normal year(1961~1990). Sunshine hours during winter barley cropping season from 1987 to 1999 decreased generally in comparison with a normal year. Considering the air temperature rise during wintering from 1987 to 1998, it might be possible to extend the cropping area of winter barley northward.