• Journal of The Korean Society of Agricultural Engineers
• /
• v.48 no.5
• /
• pp.3-15
• /
• 2006

The purpose of the study is to determine grid cell of radar relationship, and to promote the radar data on hydrology field. The study region is the Chungjudam basin with a drainage area of $6,648km^{2}$ located within the 260 km circle under the DWSR-88C C-band umbrella(Kwanak Mt Radar). Grid cell was produced to extract radar reflectivity and rainfall data of the same time and point using Arc-view software package. The grid cell size is to estimate mean correlation coefficient for $1km{\times}1km,\;2km{\times}2km,\;3km{\times}3km$ grid. The result of mean correlation coefficient showed good result(0.57) for the $1km{\times}1km$ grid cell. The 32 rainfall stations Z-R relationship was estimated in Chungjudam basin.

• Journal of Korea Water Resources Association
• /
• v.38 no.12 s.161
• /
• pp.1039-1049
• /
• 2005

The objective of this study is to produce optimal radar-derived rainfall for hydrologic utilization. The ground clutter and beam blockage effects from Mt. Kwanak station (E.L 608m) are removed from radar reflectivities by POD analysis. The reflectivities are used to produce radar rainfall data in the form of rain rates (mm/h) by the application of the Marshall-Palmer reflectivity versus rainfall relationship. However, these radar-derived rainfall are underestimated in temporal and spatial scale compared with observed one, so it is necessary to hire a correction scheme based on the gauge-to-radar (G/R) statistical adjustment technique. The selected watershed for studying the real-time correction of radar-rainfall estimation is the Soyang dam site, which is located approximately 100km east of Kwanak radar station. The results indicate that adjusted radar rainfall with the gauge measurement have reasonal G/R ratio ranged on 0.95-1.32 and less uncertainty with that mean standard deviation of G/R ratio are decreased by $9-28\%$. Mean areal precipitation from adjusted radar rainfall are well agreed to the observed one on the Soyang River watershed. It is concluded that the real-time bias adjustment scheme is useful to estimate accurate basin-based radar rainfall for hydrologic application.

• Korean Journal of Remote Sensing
• /
• v.32 no.2
• /
• pp.155-169
• /
• 2016

In this study, we developed a multi-sensor blending short-term rainfall forecasting technique using radar and satellite data during extreme rainfall occurrences in Busan and Gyeongnam region in August 2014. The Tropical Z-R relationship ($Z=32R^{1.65}$) has applied as a optimal radar Z-R relation, which is confirmed that the accuracy is improved during 20mm/h heavy rainfall. In addition, the multi-sensor blending technique has applied using radar and COMS (Communication, Ocean and Meteorological Satellite) data for quantitative precipitation estimation. The very-short-term rainfall forecasting performance was improved in 60 mm/h or more of the strong heavy rainfall events by multi-sensor blending. AWS (Automatic Weather System) and MAPLE data were used for verification of rainfall prediction accuracy. The results have ensured about 50% or more in accuracy of heavy rainfall prediction for 1-hour before rainfall prediction, which are correlations of 10-minute lead time have 0.80 to 0.53, and root mean square errors have 3.99 mm/h to 6.43 mm/h. Through this study, utilizing of multi-sensor blending techniques using radar and satellite data are possible to provide that would be more reliable very-short-term rainfall forecasting data. Further we need ongoing case studies and prediction and estimation of quantitative precipitation by multi-sensor blending is required as well as improving the satellite rainfall estimation algorithm.

• Proceedings of the Korea Water Resources Association Conference
• /
• 2009.05a
• /
• pp.1136-1140
• /
• 2009

지상강우 관측망을 이용한 강우량 측정의 대안으로서 사용되는 기상 레이더를 활용한 강우량 추정의 경우, Z-R 방정식을 이용하여 반사도를 강우량으로 환산하는 방법을 일반적으로 사용한다. 이때 발생하는 각종 오차는 레이더 장비가 가지는 기계적인 오차뿐만 아니라 Z-R 방정식이 가지는 오차 등이 있으며, 이를 보정하기 위해서 레이더를 활용하여 추정된 강우량에 지상강우량계와 레이더강우량과의 비율인 G/R비를 보정하는 방법을 일반적으로 사용한다. 본 연구에서는 이와 같이 레이더 강우량을 보정하기 위해서 사용되는 G/R비를 산정하는데 미치는 지형적인 효과를 고려하기 위해서 광덕산 레이더 유효범위 100km 내(군사분계선 이북 미포함)의 지역에 대하여 군집분석을 실시하여 크게 산악지역과 평야지역으로 구분하고, 각각 구분된 지역에 대하여 G/R 비를 산정하여 초기추정 레이더 강우량에 곱하는 mean-field bias 보정을 실시하였다. 광덕산 레이더 기상관측소의 유효범위 100km 내의 2007년, 2008년 홍수기(6/21${\sim}$9/20)기간 동안 94개 Automatic Weather Station(AWS)지점에 대하여 크게 산악지역과 평야지역으로 지역화 시키는 방법은 비계층적 군집분석 기법 중 fuzzy-c mean 방법을 적용하였다. 또한 광덕산 레이더 반사도 기본 자료는 차폐영역으로 생기는 반사도 데이터 누락을 보완하기 위하여 0도와 1.5도 sweep 합성 10분단위 uf 자료를 사용하였으며, AWS와 보정이 이루어지는 레이더 격자의 크기는 최대 4km${\times}$4km로 선정하였다. 본 연구에 있어서 검증방법은 지역을 구분하기 전과 후를 AWS 실측 관측값과 절대상대오차, 평균제곱근 오차로써 비교하였다.

• Korean Journal of Fisheries and Aquatic Sciences
• /
• v.3 no.2
• /
• pp.93-102
• /
• 1970

1. On the basis of the samples collected on the eastern coast of Koje-Do from May to September, 1969, studies have been made on the growth and the relationships between the carapace length and the body length, and between the carapace length and the body weight of Penaeus japonicus Bate. 2. The mean carapace length of P. japonicus was 51mm in May, 57mm in June, 47mm in July and 50mm in September respectively. 3. As a result of the present studies two populations of P. japonicus exist in waters around Koje-Do, namely the spring and fall spawning populations. 4. The relationship between the carapace length ($\iota$) and the body length(L) and between the carapace length and the body weight (W) are indicated by the following equations: May $$L=2.6544{\iota}+3.1258$$ $$W=1.892{\iota}^{1.9844}$$ June $$L=2.8659{\iota}+2.1796$$ $$W=1.082{\iota}^{2.4323}$$ July $$L=2.5840{\iota}+3.3090$$ $$W=1.290{\iota}^{2.3094}$$ September $$L=2.4234{\iota}+4.5775$$ $$W=1.599{\iota}^{2.1857}$$ 5. With regard to the relationships between the carapace length and the body length and between the carapace length and the body weight there is no significant difference between the populations spawning in June and September. 6. The relationships between the carapace length ($\iota$) and the body length (L) and between the carapace length and the body weight (W) for the samples cultured at three different localities are indicated by the following equations: Koje-do $$L=3.7738{\iota}+0.0805\;(r=0.934)$$ $$W=0.4690{\iota}^{3.0713}$$ Oma-do $$L=2.993{\iota}+1.6455\;(r=0.990)$$ $$W=0.6328{\iota}^{2.6579}$$ Kumdang-do $$L=3.2749{\iota}+0.9055\;(r=0.983)$$ $$W=0.5768{\iota}^{2.8076}$$ 7. During the larval stages the relationship between the body length (L) and the rearing day (D) is indicated by the following equations: Zoeal stages (1-3) L=0.1279D+0.2686 (r=0.979) Mysis (1) - Post larva (6) L=0.1697D+0.5634 (r=0.994) Post-larvs (7) - Post larvs (21) L=0.1344D+1.9501 (r=0.978)

• Journal of the Korean Society of Fisheries and Ocean Technology
• /
• v.38 no.4
• /
• pp.293-299
• /
• 2002

The anchovy scoop net fishery is one of the important in the South sea and coastal of Jeju of Korea. They are using incandescent lamp as a fishing lamp at night to gather anchovy shoals in the water surface. Fishing lamp (AC 100 V 500 W$\times$2~3 or AC 100 V 1 ㎾$\times$1) was installed at 1 m ahead of the prow and 1.5 m height from the water surface. The fishing lamp let anchovy shoals rise to the water surface and are attracted to bag net. On this study, the distribution of submarine illumination of 1㎾ and 2 ㎾ incandescent lamp were analyzed and discussed to investigate the ability of fishing lamp which can gather anchovy shoals effectively. The submarine illumination of incandescent lamp showed peak in wave length 690 nm. The relationship between submarine illumination (L) and water depth (Z) of 1 ㎾ and 2 ㎾ incandescent lamp in vertical light is 1 ㎾ : L = 3851. 9 $e^{-1.4587Z}$ $R^2$=0.9952 2 ㎾ : L= 8211.9 $e^{-1.2852Z}$ $R^2$=0.9977 The submarine illumination of 2 ㎾ incandescent lamp of 0～4 m layers appeared to be 3 to 4 times higher than 1 ㎾ incandescent lamp, and in more deep layers than 6 m appeared to be equal value of each lamp. The light of incandescent lamp (1 ㎾) pass through much better into vertical direction than horizontal, and submarine illumination of 20 m layers was 1.0 l$\chi$. Therefore, fishing lamp power is thought that 1 ㎾ incandescent lamp is more efficient than 2 ㎾ to gather anchovy shoals in depth of 15~20 m to water surface.

• Proceedings of the Korea Water Resources Association Conference
• /
• 2018.05a
• /
• pp.133-133
• /
• 2018

최근 기후변화로 인해 국지성 호우와 도시화로 인한 불투수율 증가로 내수침수 및 홍수와 같은 피해가 빈번하게 발생하고 있는 추세이다. 이로 인해 강우 관측의 정확도에 대한 논의가 지속되고 있으며, 공간적 분포를 고려할 수 있는 레이더의 활용성이 증가하고 있다. 하지만 레이더 자료는 지상강우 자료와 달리, 반사도와 강우강도 간에 관계식(Z-R 관계식)을 통한 추정치이기 때문에 실제 관측한 지상강우 자료와 함께 보정작업을 수행해야 한다. 본 연구에서는 지구통계학분야에서 제시된 공간 보간법중 하나인 크리깅 기법을 이용하여 강우의 공간적 분포를 추정하였다. 본 연구에서 사용한 크리깅 기법으로는 일반적으로 많이 사용되는 OK(Ordinary Kriging), CK(Co-Kriging), KED(Kriging with External Drift)와 RK(Regression Kriging)기법을 사용하였고, 이를 이용하여 강우장을 생성하고, 생성된 강우장과 레이더값을 비교하였다. 지상강우와 관측소 위치에서의 실제 강우값과 추정된 강우값의 정량적 평가를 실시하였으며, 레이더 강우자료의 공간분포특성과 유사성을 확인하기 위해 각 기법에서의 베리오그램을 비교하였다. 본 연구를 통해 공간적 분포를 고려하여 강우장 분포의 정확도를 높일 수 있었고, 향후 다양한 레이더 보정기법과의 비교를 통해 강우 관측의 정확도를 높일 수 있을 것으로 판단된다.

• Korean Journal of Ecology and Environment
• /
• v.54 no.1
• /
• pp.12-23
• /
• 2021

As fish communities are sensitive to natural environmental changes as well as anthropogenic pressures, their composition and characteristics help us to assess the aquatic ecosystem health. The fish fauna and the length-weight relationship of Zacco platypus in the Seomjin River system were investigated from July 2018 to May 2019. The collected species during the survey period were 49 species belong to 14 families including 19 Korean endemic and two endangered species. According to Bray-Curtis similarities, 14 sites were divided into four groups based on the fish community composition; two groups(group A, B) and two uncategorized sites(group C, D). There were significant differences between groups A and B(analysis of similarities, R=0.722, p=0.002). A similarity percentage analysis revealed that Z. koreanus(8.55%), Micropterus salmoides(6.90%), and Lepomis macrochirus (4.90%) contributed to these differences of fish assemblages between group A and B. Group A showed higher relative abundances of exotic species such as M. salmoides and L. macrochirus, while Z. platypus and Z. koreanus which are the common species in Korea, were the most dominant species in group B. Based on the length-weight relationship of Z. platypus, b values were varied from 2.82 to 3.80, indicating that growth patterns of the species were spatially different. This study could be served as baseline data for understanding fish fauna, assessing habitat characteristics based on the fauna, and identifying health conditions of Z. platypus in the Seomjin River system.

• Journal of Korean Society of Forest Science
• /
• v.13 no.1
• /
• pp.79-84
• /
• 1971

This study is, by correlation and regression analysis, on the correlation between culm height and other growth factors which are circle at eye height and length of internode. The samples were come by in Tamyang district, To sum up, the results are as follows; 1. Two growth factors are much more correlative to culm height; both simple correlation and multiple correlation between the former and the latter are significant. ($r_{yx}=0.91$, $r_{yz}=0.78$, $r_{yx{\cdot}z}=0.84$, $r_{yz{\cdot}x}=0.55$, $R_{y{\cdot}xz}=0.94$) Seeing above significance, circle at eye height is more highly correlative than length of internode. 2. The following regression equation was derived from regression analysis. y= -0.687+0.335x+0.206z. y ; culm height. x ; circle at eye height. z ; length of internode. 3. By testing of the equation, regression coefficients are as follows; ${\beta}{\neq}O$, ${\gamma}{\neq}O$, ${\beta}{\neq}O{\neq}{\gamma}$ 4. The results tested the precision of the empirical formula, standard error of standard error by percentage are as follows. $Sy{\cdot}xz=0.89$, $Sy{\cdot}xz(%)=8.14$.

• Proceedings of the Korea Water Resources Association Conference
• /
• 2008.05a
• /
• pp.997-1000
• /
• 2008

기상 레이더와 지상강우계를 이용한 실시간 강우산정기법은 전형적인 Marshall-Palmer(M-P) 방법, geostatistic 접근법을 이용한 방법, 회귀분석에 의한 방법, Kalman filter를 이용한 방법 및 실시간 weight mask를 이용한 보정 등 여러 형태가 존재한다. 본 연구에서는 실시간 강우산정을 위한 각 방법의 장단점 및 적용성을 분석하였다. 전형적인 M-P 방법은 잘 알려진 바와 같이 호우사상을 과소 추정하는 단점을 가졌으며 기존 연구자들이 제시한 바와 같이 층운형, 대류형과 같은 강우형태에 따라 다른 Z-R관계식을 가지므로 단일 Z-R관계식으로 강수를 산정함에 있어 한계를 가진다. Geostatistic 기법을 이용한 실시간 강수 산정의 경우, 지상 강우계 정보를 활용하여 강우공간분포를 개선하는 여러 기법 즉 cokriging, external drift 기법 등이 존재함에도 불구하고 과다한 계산시간, 실시간 variogram 산정과 적용상의 문제 등을 내포하고 있다. 실시간 회귀분석을 이용한 강우산정은 실제 적용에 있어 지상 강우계와 레이더 반사도사이의 선형 상관관계에 대한 결정계수가 매우 낮아 기법 적용이 간단한 장점에도 불구하고 적용에 한계를 가진다. Kalman filter기법을 이용한 실시간 레이더 강수산정은 계산시간이 여타 기법보다 많이 소요되어 실시간성을 유지하는데 한계를 가진다. 실시간 weight mask를 이용한 보정기법은 지상강우계 강우강도와 기상레이더 강우강도가 선형상관관계를 가진다는 가정이 대상지역 전체에 균일하게 적용될 수 없음에도 불구하고 기법의 적용이 간편하며 실시간 강우 공간분포를 실제 강우 관측인 지상 강우계 공간 분포 특성을 간접 강우 관측인 기상 레이더 반사도 분포와 결합하여 공간 변화 특성을 잘 나타낸다는 장점을 가지므로 실용적 적용에 있어 장점을 가진다.