• 대한원격탐사학회:학술대회논문집
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• 대한원격탐사학회 2005년도 Proceedings of ISRS 2005
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• pp.434-436
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• 2005

Analysis method using remote sensing data is one of the effective ways to research a spatial and temporal variability of the mesoscale oceanic motions. During past several decades, many researchers have been getting comprehensive results using remote sensing data with application of data fusion methods in many parts of geo-science. For this study, we took the integration and fusion of several remote sensing data, which are different data resolution, timescale and characteristics, for improving accurate analysis of variation of the Kuroshio Extension. Furthermore, we might get advanced ways to understand the variability of the Kuroshio Extension, has close relation to the spatial and temporal variation of the Kuroshio and Oyashio Current.

• 한국수자원학회:학술대회논문집
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• 한국수자원학회 2004년도 학술발표회
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• pp.691-695
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• 2004

In recent years, mary studies for efact estimation of groudwater recharge has been performed. They can be categorized into three groups : analytical method by means of groundwater recession curve, water budget analysis based on watershed, and the method using groundwater model. Since groundwater recharge rate shows the spatial-temporal variability due to hydrogeological heterogeneity, existing studies have various limits to deal with these characteristics. The method of estimating daily recharge rate with spatial-temporal variation based on rainfall-runoff model is suggested in this study for this purpose. This method is expected to enhance existing indirect method by means of reflecting climatic conditions, land use and hydrogeological heterogeneity.

• Current Research on Agriculture and Life Sciences
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• 제32권4호
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• pp.203-209
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• 2014

This study investigated characteristics of rainfall and water quality in Saemangeum area with attention to temporal and spatial distributions. A high variability in rainfall was noted during July and August. The temporal analysis of water quality data indicated that DO and TN as well as BOD, COD and SS were within national standards except for increased concentrations during spring and summer, unlike TP values that indicated poor water quality. Standard deviation showed a high variability in SS among the seasons most especially during summer. The high dispersion indicated variability in the chemical composition of pollutants where the temporal and spatial variations caused by polluting sources and/or seasonal changes were most evident for BOD and COD during winter and spring. The box plots and bar charts showed steadily low concentrations of BOD, COD, TN and TP except within Iksan and notable significant variations in SS concentrations among the monitoring stations. Thus, high pollution levels requiring intervention were identified in Mangyeong river basin with particular concern for areas represented by Iksan station. It was noted that Iksan received a considerable amount of rainfall which meant high runoff which could explain the significant pollution levels revealed in the water quality spatial distribution. Major pollution contributing pollutants within Saemangeum area were identified as SS, BOD, COD and TN. Therefore the present results could be used as a guideline for the temporal and spatial distributions analysis of both rainfall and water quality in Saemangeum watershed.

• Journal of Ship and Ocean Technology
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• 제8권2호
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• pp.20-28
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• 2004

A dynamic-thermodynamic sea ice model with 50-km spatial and 24-hour temporal resolution is used to investigate the spatial and long-term temporal variability of the sea ice cover the Arctic Basin. The model satisfactorily reproduces the averaged main characteristics of the sea ice and the sea ice extent in the Arctic Basin and its decrease in early 1990th. At times model allows to suppose partial recovery of sea ice cover in the last years of twenty century. The employment of explicit form for description of ridging gives opportunity to assume that the observed thinning is the result of reduction the intensity of ridging processes and to estimate long-term variability of probability the ridge free navigation in the different parts of the Arctic Ocean including the North Sea Route area.

• 한국농공학회논문집
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• 제63권6호
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• pp.49-60
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• 2021

BCSA (Bias-Correction and Stochastic Analog) is a statistical downscaling technique designed to effectively correct the systematic errors of GCM (General Circulation Model) output and reproduce basic statistics and spatial variability of the observed precipitation filed. In this study, the applicability of BCSA was evaluated using the ASOS observation data over South Korea, which belongs to the monsoon climatic zone with large spatial variability of rainfall and different rainfall characteristics. The results presented the reproducibility of temporal and spatial variability of daily precipitation in various manners. As a result of comparing the spatial correlation with the observation data, it was found that the reproducibility of various climate indices including the average spatial correlation (variability) of rainfall events in South Korea was superior to the raw GCM output. In addition, the needs of future related studies to improve BCSA, such as supplementing algorithms to reduce calculation time, enhancing reproducibility of temporal rainfall patterns, and evaluating applicability to other meteorological factors, were pointed out. The results of this study can be used as the logical background for applying BCSA for reproducing spatial details of the rainfall characteristic over the Korean Peninsula.

• 한국수자원학회:학술대회논문집
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• 한국수자원학회 2009년도 학술발표회 초록집
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• pp.1260-1264
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• 2009

Precipitation time series is a mixture of complicate fluctuation and changes. The monthly precipitation data of 61 stations during 36 years (1973-2008) in Korea are comprehensively analyzed using the EOFs technique and CSEOFs technique respectively. The main motivation for employing this technique in the present study is to investigate the physical processes associated with the evolution of the precipitation from observation data. The twenty-five leading EOF modes account for 98.05% of the total monthly variance, and the first two modes account for 83.68% of total variation. The first mode exhibits traditional spatial pattern with annual cycle of corresponding PC time series and second mode shows strong North South gradient. In CSEOF analysis, the twenty-five leading CSEOF modes account for 98.58% of the total monthly variance, and the first two modes account for 78.69% of total variation, these first two patterns' spatial distribution show monthly spatial variation. The corresponding mode's PC time series reveals the annual cycle on a monthly time scale and long-term fluctuation and first mode's PC time series shows increasing linear trend which represents that spatial and temporal variability of first mode pattern has strengthened. Compared with the EOFs analysis, the CSEOFs analysis preferably exhibits the spatial distribution and temporal evolution characteristics and variability of Korean historical precipitation.

• 대한원격탐사학회:학술대회논문집
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• 대한원격탐사학회 2006년도 Proceedings of ISRS 2006 PORSEC Volume I
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• pp.118-121
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• 2006

Variations in the extent and dispersal of river plume are important in the study of coastal environment. The objectives of this study are to examine relationship between satellite detected plume area and river discharge and to clarify the temporal and spatial dynamic of plume from Tokachi River, Hokaido, Japan. We used 1.1 km spatial resolution of SeaWiFS normalized water-leaving radiance (nLw) images from 1998 to 2002. Supervised maximum likelihood classification was implemented to define classes of surface water optical properties. Satellite observed plume area was correlated to the amount of river discharge from April to October. First mode (44% of variance) of EOF analysis shows the turbid plume distribution resulting from re-suspension by strong wind mixing along the coast during winter. This mode also shows plume distribution along-shelf direction in spring and late summer. Second mode (17% of variance) shows spring pattern across-shelf direction due to strong discharge of snow melting water.

• 대한토목학회논문집
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• 제30권3B호
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• pp.285-293
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• 2010

지표에서의 토양수분은 수문학적, 생태학적 과정에서 지표면과 대기 사이의 물과 에너지의 교환을 조절하는 매우 중요한 인자로써 최근 이의 시공간적 변동성에 대한 연구가 활발하게 진행되고 있다. 본 연구에서는 2004년 6~9월에 걸쳐 추진되었던 Soil Moisture Experiment 2004(SMEX04) 프로젝트를 통하여 측정된 미국 Arizona 주의 Walnut Gulch Experimental Watershed 유역에 대한 토양수분 데이터를 이용하여 건조 지역에서의 토양수분의 시공간적 변동성을 통계적 방법으로 해석하였다. 시간 안정도를 분석하여 각 지점의 강우사상에 대한 민감도를 분석하였고 공간 변동성 분석을 통해 유역 내 강우관측소 주변 5개 지점을 대상으로 각 지점의 평균토양수분과 이의 표준편차 및 변동계수와의 관계를 파악하였다. 연구 결과, 대상지역에서 토양수분의 공간적인 분포는 대수정규분포가 적합하다는 것과 건조지역에서 보이는 공통된 특징인 높은 공간적 변동성을 확인할 수 있었다. 또한 시간 안정도 분석을 통해 지점별로 시간과 강우 발생에 대해 민감한 정도를 분석하였으며, 강우사상이 토양수분에 큰 영향을 주는 인자인 것을 확인할 수 있었다. 본 연구에서 도출된 토양수분의 시공간적 변동 특성은 차후 인공위성 토양수분 데이터의 retrieval algorithm을 개선하는데 도움이 될 것이다.

• 한국지하수토양환경학회:학술대회논문집
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• 한국지하수토양환경학회 2006년도 총회 및 춘계학술발표회
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• pp.282-285
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• 2006

This study is to present the method for estimating groundwater recharge with temporal-spatial variability using the SWAT model which can represent the heterogeneity of the watershed. The SWAT model can simulate daily surface runoff, evapotranspiration, soil storage, recharge, and groundwater flow within the watershed. The model was applied to Musimcheon watershed located in the upstream of Mihocheon watershed. Hydrological components were determined for the period 2001 - 2004, and the validity of the results was tested by comparing the estimated runoff with the observed runoff data at the outlet of the catchment. The results of temporal and spatial variations of recharge were presented, This study suggests that variations in recharge can be significantly affected by subbasin slope as well as land use changes.

• 한국물환경학회지
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• 제37권3호
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• pp.204-216
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• 2021

It is important to understand the factors influencing the temporal and spatial variability of water quality in order to establish an effective customized management strategy for contaminated aquatic ecosystems. In this study, the spatial diversity of the 5-year (2015 - 2019) average total phosphorus (TP) concentration observed in 40 Total Maximum Daily Loads unit-basins in the Nakdong River watershed was analyzed using 50 predictive variables of watershed characteristics, climate characteristics, land use characteristics, and soil characteristics. Cross-correlation analysis, a two-stage exhaustive search approach, and Bayesian inference were applied to identify predictors that best matched the time-averaged TP. The predictors that were finally identified included watershed altitude, precipitation in fall, precipitation in winter, residential area, public facilities area, paddy field, soil available phosphate, soil magnesium, soil available silicic acid, and soil potassium. Among them, it was found that the most influential factors for the spatial difference of TP were watershed altitude in watershed characteristics, public facilities area in land use characteristics, and soil available silicic acid in soil characteristics. This means that artificial factors have a great influence on the spatial variability of TP. It is expected that the proposed statistical modeling approach can be applied to the identification of major factors affecting the spatial variability of the temporal average state of various water quality parameters.