• 제어로봇시스템학회:학술대회논문집
• /
• 2005.06a
• /
• pp.2468-2473
• /
• 2005

Because the rain gauges of tipping bucket type can easily use the digital signal, the rain gauges are widely used for the meteorological observation. In general, the resolution of rain gauges of tipping bucket type can be categorized by the 0.1mm, 0.5mm, and 1.0mm classes. But, the error of the tipping bucket rain gauges is made by the intensity of rainfalls and is expected to make the standard calibration method for error measurement. Thus, we developed the hardware of standard calibration facility for rain gauges by weighting measurement method and proposed the standard procedure by rainfall intensity in this study Also, we calculated the error for the rainfall intensity and obtained useful result through the proposed calibration method.

• Journal of Advanced Navigation Technology
• /
• v.10 no.4
• /
• pp.356-363
• /
• 2006

The demand for digital multimedia service using Ka band satellite communication are growing rapidly. So, in this paper, we have analyzed rain attenuation with typical model, and proposed prediction model of rain attenuation in high frequency(20 GHz). This paper illustrates Korea rain attenuation characteristics at the Ka band Koreasat beacon frequency based on the theoretical and empirical approaches and seek for efficient techniques by rain attenuation estimate and analyzed performance of adaptive modulation system. Propose prediction model of rain attenuation and parameter of satellite link can be available for the Ka band satellite communication.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
• /
• v.10 no.5
• /
• pp.701-710
• /
• 1999

To predict rain attenuation accurately, we must know scattering characteristics of rain-drops for real drop shapes. In this paper, the scattering characteristics of rain-drops are analyzed by an analytical model, and the differences in the characteristics of the forward scattering amplitudes for three different rain-drop shapes are compared. Using the results for the Pruppacher-Pitter's real rain-drop shaper, the specific rain attenuation in domestic environment is predicted, and the difference from the ITU-R model is compared and analyzed.

• Journal of Institute of Control, Robotics and Systems
• /
• v.12 no.8
• /
• pp.818-823
• /
• 2006

Because the rain gauges of tipping bucket type can easily use the digital signal, the rain gauges are widely used for the meteorological observation. In general, the resolution of rain gauges of tipping bucket type can be categorized by the 0.1mm, 0.5mm, and 1.0mm classes. But, the error of the tipping bucket rain gauges is made by the intensity of rainfalls and is expected to make the standard calibration method for error measurement. Thus, we developed the hardware of standard calibration facility for rain gauges by weighting measurement method and proposed the standard procedure by rainfall intensity in this study Also, we calculated the uncertainty for the rainfall intensity and obtained useful result through the proposed calibration method.

• Proceedings of the IEEK Conference
• /
• 2002.07c
• /
• pp.1575-1577
• /
• 2002

In this research we propose a method far rain rate estimation by using Doppler spectrum's data of wind profiler. The Doppler spectrum is used to calculate the wind velocity and wind direction. But in this research uses the parameters from Doppler spectrum, it calculates the rain rate. The rain rate estimation in this method will be compared to the obtained rain rate from the surface rain gauge. Two equipments are installed in the same area. The correlation coefficient between rain rate measuring method is 0.65.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
• /
• v.9 no.3
• /
• pp.410-418
• /
• 1998

Rain-attenuation and cross-polarization models for millimeter-wave propagation are discussed and compared with measurements in the various countries. Rain-rate conversion model which converted <$\tau$minutes rain-rate data to one minute rain-rate data, which is applicable for domestic environments are also discussed. Using the converted domestic rain-rate data, probability distributions of rain attenuation and cross-polarization discrimination are computed for various models, and the results are compared with each other.

• Korean Journal of Plant Resources
• /
• v.13 no.2
• /
• pp.131-139
• /
• 2000

The effects of the simulated acid rain on the growth response and water status of Glycine soja was observed in 2 months-old seedlings. The seedlings were treated with acid rain(pH 3.5), three times per week. Glycine soja showed significant reduction in the total length, total weight, dry weight, water contents and top/root ratio after treatment of simulated acid rain(pH 3.5) for 56 days. The growth of shoot was more susceptible to acid rain than that of roots. On the contray, Number of lateral roots, water saturation deficit and epidermis transpiration was higher than that of control(pH 5.6) after 56 days treatment of simulated acid rain.

• Journal of electromagnetic engineering and science
• /
• v.8 no.2
• /
• pp.84-89
• /
• 2008

In a wireless channel above microwave frequency, rain attenuation is very important. In order to predict rain attenuation, 1-min. rain rate distribution is required. This paper discusses appropriate conversion methods to estimate 1-minute rain rate from that of other integration time. Based on the measurement data filed in ITU-R WP3J including ETRI data for 6 consecutive years, distributions of rain rate with 1-, 5-, 10-, 20-, 30-minute integration time were analyzed, both on the global and regional basis, and the parametric relationship between the statistical characteristics of 1-minute and other measurement data were investigated to deduce the conversion methods. It is shown that the global model works good with good accuracy for 5-, 10-, 20-min integration time, and the global model is also applicable globally with good accuracy for 5-, 10-, 20-min integration time. The global conversion model was adopted last year as an ITU-R document for new recommendation. The regional conversion model would also be very useful for locations of similar climatic zone.

• Journal of Korean Society for Atmospheric Environment
• /
• v.9 no.2
• /
• pp.147-153
• /
• 1993

From March 1990 to August 1991, every each 5mm bulk precipitation samples were collected at one residental area in Taejon City to investigate chemical characteristics of acid rain. Major ion concentrations of rain samples $(pH, SO_4^{2-}, NO_3^-, CL^-, NH_4^+, Na^+, K^+, Ca^{2+}, Mg^{2+})$ were analysed and compared with the concentration of air pollutants (T. S. P, $SO_2, NO_x$) that were measured by Ministry of Environment. The results of statistical analysis are as followings. Rain pH was relatively high on October and January and relatively low on August, November and February. Major anion is sulfate, and it's concentration is 2.36 times higher than nitrate's, and major cations are ammonium, sodium and calcium ion. Monthly variation of sulfate and calcium concentrations are higher than the others. Ion concentration and rain pH were correlated negatively with rainfall amount. Major ions in rain samples were $SO_4^{2-}, NO_3^-, NH_4^+, Ca^{2+}$ and regression equations are proposed by multiple regression of measured data. Also, regression equation between air pollutants(T. S. P, $SO_2$) and $SO_4^{2-}, Na^+, K^+, Ca^{2+}, Mg^{2+} ions in rain samples were made. From this wer can predict rain pH.

• Journal of Environmental Science International
• /
• v.18 no.10
• /
• pp.1115-1121
• /
• 2009

The purpose of this study is to estimate the impact of rainfall measurement according to the installation conditions of rain gauges: windbreak, grass mat, installation elevation or obstacle. Rain gauges were installed by the standards of Korea Meteorological Administration(KMA), and the rainfall measurement was conducted daily unit during two years(2007~2008). In conclusion, observed error of rain gauge did not affect whether windbreak was installed or not. If there is the obstacle around rain gauge, average error rate was increased about 3.3%: (2007year-2.49%, 2008year-4.10%). If rain gauge is located in a high place, average error rate was increased about 4.89%. Additionally, the observed error of rain gauge according to the wind speed has a positive correlation with obstacle and installation elevation and has a negative correlation with windbreak and has no affection with grass mat.