• Proceedings of the KSRS Conference
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• 2006.03a
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• pp.145-148
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• 2006

새로 조성된 간척지 갯벌이 건조 수축하면 지반 침하와 더불어 토양 내로의 마이크로파의 침투 깊이가 증가한다 따라서 인공위성 DInSAR를 이용하여 지반 침하량을 구하고자 할 때, 건조 시 동시에 발생하는 마이크로파의 개펄 침투 현상을 규명하여 보정해 주어야 한다. 이를 위하여 다편광 산란계(Polarimetric Scatterometer)를 구성하여 건조 개펄에 대한 실내실험을 실시하였다. PolScat의 구성은 5.0-5.6GHz 대역의 dual-polarization square horn antenna를 사용하였으며 Agilent 8753ES 벡터 네트워크 분석기를 사용하였다. 길이 2m, 폭 2m, 높이 20cm의 개펄 샘플을 약 6주 동안 실내에서 건조시켜 위상을 측정한 결과 지반 침하와 함께 약 4mm의 마이크로파 투과현상이 발견되었다. 따라서 인공위성 DInSAR 지반침하량 계산에 있어서 반드시 토양 수분에 따른 마이크로파의 토양 침투 깊이를 보정해 주어야 함이 밝혀졌다.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.19 no.5
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• pp.556-561
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• 2008

The characteristics of microwave reflectometry, which is based on the technologies of FM radar and is applied as a non-invasive method to examine the properties including density distribution of inhomogeneous media, is investigated. The microwave reflectometry system requires not only an optimized system hardware but as well as the understanding of system response from the media under test in order to provide the system solution describing the object under test quantitatively. The introduction of microwave reflectometry especially in the area of applied plasma physics has been relatively new and the number of usage is found to be increasing gradually. The experimental method to characterize the microwave system as a device to examine the properties of plasma is explained. The microwave reflectometry signals consist of the cutoff signals which originate from the region where most of the reflected power comes from and the scattered signals which result as an interaction of the microwave and the density perturbations. This paper describes the experimental results of the scattered signal from the microwave reflectometry, such as the wavenumber dependence and the sensitivity on density perturbation, and the comparison of the characteristics with those from the numerical simulations and those from the cutoff signals.

• 한국지구물리탐사학회:학술대회논문집
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• 2006.06a
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• pp.271-276
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• 2006

In this paper a polarimetric airborne SAR measurement has been used to study the radar polarimetric characteristics in the intertidal area on the south coastof the Korea. The L-band NASA/JPL airborne SAR (AIRSAR) data, which were acquired on the intertidal zone during PACRIM-II Korea campaign on September 30, 2000, were used for this research. The most intertidal zones of Yeoja Bay are composed of muddy soils with high silt and clay percentage. Models of microwave scattering from rough surfaces, i.e., semi-empirical model, and Extended Bragg model, were applied to investigate the surface characteristics of intertidal zones.

• Proceedings of KOSOMES biannual meeting
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• 2006.11a
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• pp.193-199
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• 2006

This article reviews several microwave instruments employed in observation and analysis of tropical cyclones (TCs), typhoon, and hurricanes. Microwave signals are useful for observing tropical cyclones with severe storms since it isn't severely absorbed by the clouds and rain in the storm. The instruments discussed include scatterometers, microwave radiometers, synthetic aperture radars (SARs), and rain radar from space. The date such as winds, rainfall and cloud-distribution in the TCs obtained by microwave instruments provide important informations for forecasting the intensity and path of the typhoon. For example, there're wind-distribution provided by SSM/I which has a wide swath, detailed wind fields from ERS-1, 2 scatterometers and RADARSAT-1 SAR and TRMM's rain radar pro 떠 ding high resolution. Operational satellite instruments lunched recently have improved upon the problems of low resolution and narrow swath indicated at the beginning microwave remote sensing. Understanding and practical using sufficiently about the microwave instruments will serve for searching the features such as generation and development of the TCs.

• Geophysics and Geophysical Exploration
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• v.15 no.1
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• pp.16-22
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• 2012

In this study, we setup a ground-based scatterometer using an antenna of which the center frequency is 9.5 GHz (X-band), and measured radar backscatterings from air/ice and ice/water interfaces to extract ice thickness. Both of air/ice and ice/water interfaces make strong radar backscatterings and so we can clearly identify two peaks in measured data by scatterometer. By using the distance of two peaks and refractive index of ice, we confirmed that it is possible to measure ice thickness. Field survey was performed at the downstream of Jiam River flowing into Chuncheon Lake. We measured radar backscattering from river ice along a survey path and extracted ice thickness. The ice thickness map of the downstream of Jiam River was produced by using kriging which is one of well known interpolation methods. The ice thickness was about 50 cm along the mainstream while ice was thin as 30 ~ 40 cm at a fast-flowing meander. Ice thickness was particularly thinner at some locations than that of surrounding areas even in the mainstream region of constant flow. This was because of impurities in ice or artificially formed refrozen holes after fishing. We expect that this study helps to expand utilization field of X-band SAR and airborne scatterometer system.

• The Magazine of the IEIE
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• v.13 no.4
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• pp.32-39
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• 1986

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.11 no.5
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• pp.763-772
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• 2000

The Radiative Transfer Model(RTM) for computation of microwave polarimetric backscattering coefficients of a various types of vegitation canopies has been examined in this paper. Leaves in the vegitation canopy are modeled by rectangular resistive sheets, which sizes and orientations are randomly distributed. Surface roughness and soil moisture of soil surface are considered in this computation. The backscattering coefficients of grasslands are computed for various values of radar parameters and canopy parameters. A polarimetric scatterometer radar system at 15 GHz has been used for measurement of the scattering coefficient from a grass canopy and a cabbage canopy. The computation results obtained by the RTM for the canopies are compared with the measurement for examination of the RTM.

• Korean Journal of Soil Science and Fertilizer
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• v.45 no.4
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• pp.503-510
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• 2012

Microwave radar can penetrate cloud cover regardless of weather conditions and can be used day and night. Especially a A ground-based polarimetric scatterometer operating at multiple frequencies can continuously monitor the crop conditions. We analyzed scattering characteristics of rice and soybean using pauli decomposition method. Surface scattering (${\alpha}$) is the dominant component over the entire stages for all bands and pauli decomposition value was the highest for L-band. Double bounce scattering (${\beta}$) and volume scattering (${\gamma}$) were approximately equal for C-band and volume scattering was higher than double bounce scattering for X-band in rice field. In soybean, double bounce scattering becomes higher than volume scattering during the R2 stage (DOY 224) and there was a significant difference between the two components after the R4 stage (DOY 242) for L-band. The maximum growth stage of soybean can also be detected using L-band double bounce scattering. The peak of double bounce effect coincides with the peak of growth biophysical variables on DOY 271. We found that pauli decomposition can provide insight on the relative magnitude of different scattering mechanisms during the rice and soybean growth cycle.

• The Magazine of the IEIE
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• v.42 no.4
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• pp.50-63
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• 2015

• 한국지구물리탐사학회:학술대회논문집
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• 2010.10a
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• pp.53-54
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• 2010