Publications by authors named "Sangdan Kim"

Streamflow prediction in ungauged basins (PUB) remains a significant challenge in water resource planning and management. Although recent studies have proposed various approaches to reduce prediction errors using data-driven models (DDMs), further efforts are needed to improve applicability and accuracy of predictions in ungauged basins. This study proposes a framework that utilizes DDM as a post-processor to enhance the PUB performance of process-based models (PBMs) or DDMs and investigates its applicability.

View Article and Find Full Text PDF

The impacts of drought range from water supply for humans to ecosystems. Drought affects river water quality by disturbing the hydrological regime in a variety of ways, and can degrade water quality by reducing surface and groundwater availability. In particular, drought-induced low flows, reduced nutrient dilution, and extreme increases in water temperature affect various water quality parameters in streams.

View Article and Find Full Text PDF

Information on water availability in basins can be crucial for making decisions for effective water resource management in basins. As the operation of hydrometric stations in Korea is mainly focused on flood season and large rivers, most basins have lack or no observed data. Consequently, this complicates water resource planning and management.

View Article and Find Full Text PDF

Drought is a natural phenomenon that can occur in all climatic zones, and is persistent and regionally widespread. Extreme drought caused by climate change can have serious consequences for freshwater ecosystems, which can have significant social and economic impacts. In this study, the effect of meteorological drought on river water temperature was analyzed probabilistically in order to identify the risk of river water temperature stress experienced by the aquatic ecosystem when a meteorological drought occurs.

View Article and Find Full Text PDF

Drought caused by various meteorological factors negatively affects vegetation. Constructing a joint probability distribution between vegetation and drought information may be appropriate to understand the vulnerability of vegetation to drought. In this study, a copula-based trivariate joint probability model is proposed to investigate the effects of various aspects of meteorological drought on vegetation (vegetation drought).

View Article and Find Full Text PDF

The drought index, which mainly focuses on the moisture supply side of the atmosphere, which has been mainly used in the field of drought monitoring, has limitations that cannot reflect drought caused by changes in various climate variables such as an increase in surface air temperature due to global warming. To overcome these limitations, various evaporation demand-based drought indices have been proposed, focusing on the aspect of atmospheric moisture demand. However, drought indices that consider only precipitation or the demand for atmospheric evaporation are difficult to comprehensively interpret drought caused by various climatic factors.

View Article and Find Full Text PDF

This paper presents a design method by which the overflow risk related to a detention for managing nonpoint pollutant sources in urban areas can be evaluated. The overall overflow risk of a nonpoint pollutant sources control detention can be estimated by inherent overflow risk and operational overflow risk. For the purpose of calculating overflow risk, the 3-parameter mixed exponential distribution is applied to describe the probability distribution of rainfall event depth.

View Article and Find Full Text PDF

One-dimensional SnO(2) nanomaterials with wide bandgap characteristics are attractive for flexible and/or transparent displays and high-performance nano-electronics. In this study, the crystallinity of SnO(2) nanowires was regulated by controlling their growth temperatures. Moreover, the correlation of the crystallinity of nanowires with optical and electrical characteristics was analyzed.

View Article and Find Full Text PDF

The aim of this article was to study the effects of land use change and water reuse options on an urban water cycle. A water cycle analysis was performed on the Goonja drainage basin, located in metropolitan Seoul, using the Aquacycle model. The chronological effects of urbanization were first assessed for the land uses of the Goonja drainage basin from 1975 to 2005, where the ratio of impervious areas ranged from 43% to 84%.

View Article and Find Full Text PDF

We report a versatile hybrid device consisting of one-dimensional ZnS and Te-doped ZnS (ZnS:Te) nanowires (NWs) upon two-dimensional multilayer graphene films (MGFs). Single-crystalline ZnS and ZnS:Te NWs were grown directly on a MGF without a catalyst, and exhibited blue-green and blue emission peaks of ∼ 503 and ∼ 440 nm. A field emission light emitter using ZnS:Te NWs on a MGF was demonstrated, and it indicates excellent contact properties between the NWs and MGFs.

View Article and Find Full Text PDF

Tunable-white-light-emitting materials are developed by combining two single-crystal oxide nanowire materials-ZnO and SnO(2)-having different light emissions. The tuning of white-light emission from cool white to warm white is achieved for the first time by adjusting the growth sequence and growth time of the ZnO and SnO(2) nanowires. Combined ZnO:SnO(2) nanowire arrays yield a desired emission color from (0.

View Article and Find Full Text PDF

Most related literature regarding designing urban non-point-source management systems assumes that precipitation event-depths follow the 1-parameter exponential probability density function to reduce the mathematical complexity of the derivation process. However, the method of expressing the rainfall is the most important factor for analyzing stormwater; thus, a better mathematical expression, which represents the probability distribution of rainfall depths, is suggested in this study. Also, the rainfall-runoff calculation procedure required for deriving a stormwater-capture curve is altered by the U.

View Article and Find Full Text PDF