• Proceedings of the Korea Water Resources Association Conference
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• 2015.05a
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• pp.474-474
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• 2015

Horton 지수는 유역에 대한 수문순환의 특성을 정량화하는 지수로서 유역의 습윤량과 기화량의 비로 산출된다. 습윤량과 기화량은 토양 수분과 밀접한 관계를 가지므로 추계학적 거동에 따른 토양수분의 동역학모형을 파악하여 Horton 지수를 산출할 수 있다. 본 연구에서는 추계학적인 토양수분수지 모형을 이용하여 서울, 부산, 대구, 제주 지역을 대상으로 30년간 일 기상자료(강우량, 일 평균기온, 풍속, 상대습도, 일조시간)을 이용하여 Horton 지수를 각각 산출하였으며 Horton 지수에 대한 변동성 분석을 실시하였다. 분석 결과, 모든 대상 유역에서 기후의 계절성에 의하여 Horton 지수가 작아짐을 확인할 수 있었다. 하지만 습윤한 기후를 가진 서울과 건조한 기후를 가진 대구에서는 각각 연 강우량이 많거나 연 강우량이 적은 해에 Horton 지수에 미치는 기후의 계절성의 영향력이 줄어듦을 살펴볼 수 있었다.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.30 no.5B
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• pp.471-477
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• 2010

In this study, the variability of the Horton index which is ratio of vaporization and wetting water is investigated using a conceptual soil water balance model. From the proposed model, the steady-state soil water probabilistic density function is derived through meteorological and watershed characteristics and then the sensitivity of Horton index to the precipitation occurrence rate and the mean of wet day precipitation is examined. As a result, the inter-annual variability of the Horton index is lower than that of precipitation and they showed the strong negative correlation. It is also shown that although precipitation is not varied, the Horton index can be varied due to the fluctuation of the precipitation occurrence rate and the mean of wet day precipitation. In addition, it is presented that there is a non-linear relationship which has a critical point switching proportional or inverse relationship between the Horton index and two main characteristics of precipitation process.

• Journal of Korea Water Resources Association
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• v.43 no.6
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• pp.533-541
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• 2010

It is basic for a flood prediction to calculate direct runoff from rainfall in a basin by the rainfall-runoff model. The direct runoff is calculated from rainfall excess or effective rainfall based on a rainfall-runoff model. The total rainfall minus rainfall loss equals rainfall excess with time. This loss can be treated equal to an infiltration loss under the assumption that the infiltration is a major one among the losses in the rainfall-runoff model. Practically obtaining the infiltration loss $\Phi$ index method, W index method or modified ones of these have been used. In this study it is assumed the loss of rainfall in a basin be a well-known Horton infiltration mechanism. And in case that the parameter set is given in the Horton infiltration model a procedure and assumption for calculating hourly infiltration loss and rainfall excess are offered and the results of its application are compared with those of $\Phi$ index method. By this study it is well shown the value of Horton infiltration function is exponentially decay with time as the Horton infiltration mechanism.

• Journal of Korea Water Resources Association
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• v.46 no.7
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• pp.735-744
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• 2013

The effect of climate and landscape characteristics on hydrologic partitioning and vegetation response is analyzed in this study. After quantifying hydrologic partitioning using the Horton index, the relation between regional climate characteristics and the Horton index is investigated. In addition, using the comparison between the predictability of the Horton index with only regional climate characteristics and the predictability of the Horton index with landscape characteristics as well as regional climate characteristics, the relative contribution of landscape characteristics on hydrologic partitioning is analyzed. Finally, investigating the predictability of the aridity index and Horton index on the normalized difference vegetation index, the effect of climate and landscape characteristics on vegetation response is estimated.

• Journal of Korea Water Resources Association
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• v.39 no.11 s.172
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• pp.977-984
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• 2006

The parameters in the Horton's model which has well known as typical infiltration model were determined by the use of the optimization technique. It was assumed the initial infiltration capacity in this model was related to the antecedent precipitation per 10 days with linear combination. And both the parameters of the ultimate infiltration capacity and the decay factor were determined uniquely on a basin. Thus the optimal model's parameters representative to a basin were obtained and the Horton's infiltration equations by rainstorm events were determined. The data of ten rainstorm events for this study were observed at the Jeonjeokbigyo station located at the Selmacheon experimental basin that was $8.5km^2$ wide in the Imjin river.

• Journal of Wetlands Research
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• v.13 no.1
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• pp.35-44
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• 2011

In order to explore vegetation adaptation to climate variability and the impacts on water balance dynamics, the inter-regional and the inter-annual variability of both water availability and vegetation productivity are investigated. The Horton index, which is the ratio between actual evapotranspiration and catchment wetting as a measure of vegetation water use at catchment-scale, is revisited to quantify the effects of growing-season water availability on hydrologic partitioning at catchment scale. It is shown that the estimated Horton index is relatively constant irrespective of inter-annual climate variability. In addition, the Horton index is compared with catchment-scale vegetation rain use efficiency. The results show that there is an interesting pattern in the response of vegetation water use to water availability. When water becomes the limiting factor for vegetation productivity, the catchment-scale vegetation rain use efficiency converges to a common maximum value in agreement with earlier findings at the ecosystem level.

• Journal of Korea Water Resources Association
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• v.32 no.5
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• pp.565-577
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• 1999

The geometric patterns of a stream network in a drainage basin can be viewed as a "fractal" with fractal dimensions. Fractals provide a mathematical framework for treatment of irregular, ostensively complex shapes that show similar patterns or geometric characteristics over a range of scale. GIUH (Geomorphological Instantaneous Unit Hydrograph) is based on the hydrologic response of surface runoff in a catchment basin. This model incorporates geomorphologic parameters of a basin using Horton's order ratios. For an ordered drainage system, the fractal dimensions can be derived from Horton's laws of stream numbers, stream lengths and stream areas. In this paper, a fractal approach, which is leading to representation of a 2-parameter Gamma distribution type GIUH, has been carried out to incorporate the self similarity of the channel networks based on the high correlations between the Horton's order ratios. The shape and scale parameter of the GIUH-Nash model of IUH in terms of Horton's order ratios of a catchment proposed by Rosso(l984J are simplified by applying the fractal dimension of main stream length and channel network of a river basin. basin.

• Proceedings of the Korea Water Resources Association Conference
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• 2011.05a
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• pp.89-89
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• 2011

한 유역에서 유출 모형의 성공을 좌우할 수 있는 중요한 요소 중 하나는 강수 손실량(precipitation loss)을 결정하는 것이다. 손실량은 홍수 예측이나 수자원 평가를 위한 유출 모형의 주요 입력 자료가 된다. 만족할 만한 유출 모형을 구현하기 위해서는 손실량의 정확한 평가가 요구된다(Najafi, 2003). 총 강우량 중에서 손실량을 뺀 초과 강우량 또는 유효 강우량은 치수적 측면이든 이수적 측면에서 요구되는 직접 유출량(direct runoffs)에 상당하는 규모로서 유출 모형에서 매우 중요하다. 이제까지 많은 경우에 직접 유출되는 유효 강수량은 총강수량에서 주요 손실량 성분인 침투량을 감하여 산출하여 왔다. 이 때 침투량은 호우사상별로 적게는 유출량의 30%에서 많게는 100%까지 차지할 만큼 주요한 손실 성분으로 취급되었다(Chow, 1964 ; Singh, 1989). 침투량을 산정하기 위한 기존 모형내 포함되는 매개변수 값은 실용적으로 잘 정립되지 않았기 때문에 유출 모형에 실제 적용하는데 어려움이 있다. 한편 침투량 산정 모형 중에 Horton 모형은 가장 잘 알려져 있는 모형 중 하나이다(Horton, 1939 ; 1940). 후속 성과(Blake et al., 1968; Rawls et al., 1976)은 있었지만 모형내 매개변수 값을 결정해야 하는 실용상의 어려운 점이 있다(Singh, 1989). 그리고 국내 초과 강수량 산출 모형에 관한 연구사례가 다수(조홍제,1986; 남선우와 최은호, 1990; 정성원과 김승, 1991; 안태진 등, 2000; 박햇님과 조원철, 2002; 유주환, 2006) 있었지만 시간적으로 연속함수를 갖는 Horton 침투 모형을 실무적으로 이산화 하여 적용할 수 있도록 하는 방법의 절차 및 원칙이 제시되지 않아 유출 모형에 직접 적용하기 쉽지 않은 형편이다. 이에 본 발표에서는 한 유역에서 Horton 매개변수를 결정한 기존 연구(2006, 유주환)의 성과를 적용한 Horton 침투모형을 강수사상별 이산화한 시간별로 적용하는 절차와 적용 원칙을 소개하고자 한다.

• Proceedings of the Korea Water Resources Association Conference
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• 2009.05a
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• pp.107-111
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• 2009

The parameters in the Horton's model which has well known as typical infiltration model were determined by the use of the optimization technique. It was assumed the initial infiltration capacity in this model was related to the antecedent precipitation per 10 days with linear combination. And both the parameters of the ultimate infiltration capacity and the decay factor were determined uniquely on a basin. Thus the optimal model's parameters representative to a basin were obtained and the Horton's infiltration equations by rainstorm events were determined. The data of ten rainstorm events for this study were observed at the Jeonjeokbigyo station located at the Selmacheon experimental basin that was $8.5\;km^2$ wide in the Imjin river.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.34 no.3
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• pp.785-794
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• 2014

Hydrologic responses in watershed are determined by complex interactions among climate, land use, soil and vegetation. In order to effectively investigate hydrologic response in watershed, one needs to analyze the characteristics of climate as well as other factors. In this study, the relative contribution of climate factors and watershed characteristics on hydrologic response is investigated by using hydrologic indexes such as the aridity index and the Horton index. From preliminary analysis, it is shown that the Horton index is proper in terms of classifying hydrologic responses in main natural watersheds of south Korea. While climate and watershed characteristics both contributes to hydrologic responses, the degree contributed from each factor is changed depending on annual climatic humid conditions. In dry conditions, the climate factor is the predominant influence on hydrologic responses. However, in wet conditions, the contribution of watershed characteristics on hydrologic responses is relatively increased.