• Atmosphere
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• v.20 no.1
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• pp.27-35
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• 2010

This study analyzes the climate change in Korea and its impact on the occurrence of forest fire events. The forest fire occurrences in Korea tend to concentrate around large cities. In addition, the spatial distribution of the forest fire occurrence seems to agree with local climate conditions. Though the occurrence of the forest fire shows strong interannual variation, it also exhibits a positive trend. Because the forest fire frequently occurs during early spring, we examined long term climate variability in Korea for the early spring seasons. The climate change in Korea generally has brought warmer, drier, and less precipitable conditions during the early spring. The changes of the atmospheric conditions provide favorable condition for the forest fire. The climate changes in Korea also depict distinct spatial variability according to the atmospheric variables. We compared the regional trend of the fire occurrence with the climate trends. The results show the sharpest growing in the forest fire occurrence over southwest of Korea. This study suggests that the decrease in the precipitation day might affect the sharp increasement of the forest fire occurrence in the southwest of Korea.

• Fisheries and Aquatic Sciences
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• v.5 no.3
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• pp.219-228
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• 2002

Based on the five-year (October 1992 through September 1997) Topex/Poseidon altimeter measurements, we describe the statistical characteristics of the eddy variability in the East Sea in terms of sea surface height anomaly, slope variability, and eddy kinetic energy (EKE). The sea surface height anomalies in the East Sea are produced with standard corrections from Topex/Poseidon measurements. In order to eliminate the high frequency noise in the sea surface height anomaly data, the alongtrack height anomaly data was filtered by about 40 km low-pass Lanczos filter based on Strub et al. (1997) and Kelly et a1. (1998). We find that there exists a distinct spatial contrast of high eddy variability in the south and low eddy energy in the north, bordering the Polar Front. In the northwestern area $(north\;of\;39^{\circ}N\;and\;west\;of\;133^{\circ}E)$ from the Polar Front where the eddies frequently appear, the EKE is also considerabel. The high kinetic energy in the southern East Sea reveals a close connection with the paths of the Tsushima Warm Current, suggesting that the high variability in the south is mainly generated by the baroclinic instability process of the Tsushima Warm Current. This finding is supported by other studies (Fu and Zlontnicki, 1989; Stammer, 1997) wh.ch have shown the strong eddy energy coupled in the major current system. The monthly variation of the EKE in both areas of high and low eddy variability shows a strong seasonality of a high eddy kinetic energy from October to February and a relatively low one from March to September. The sequential pattern of wind stress curl shows resemblance with those of monthly and seasonal EKE and the two sequences have a correlation of 0.82 and 0.67, respectively, providing an evidence that wind stress curl can be the possible forcing for the monthly and seasonal variation of the EKE in the East Sea. The seasonality of the EKE also seems to correlate with the seasonality of the Tsushima Warm Current. There also exists the large spatial and interannual variabilities in the EKE.

• Journal of the Korean Geographical Society
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• v.28 no.3
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• pp.193-199
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• 1993

The interannual fluctuation, trends and perio-dicties in summer rainfall of South Korea were analyzed primarily by using Mann-Kendall rank method and Power Spectrum analysis for the period from 1920 to 1985. Their relations to Indian summer monsoon rainfall have also been examined. Increasing or decreasing rainfall tendencies are not found in South Korea. In Power Spectrum alalysis, 2.5 years periods are predominent at the 95 per cent confidence level in south Korea as a whole and Pusan. Also the period of 11.0 years is found in Seou. There are another prominent spectral peaks at 2.4, 3.1, 6.2 and 7.3 years period, which are significant at 90 per cent confidence level.

• Journal of Environmental Science International
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• v.5 no.5
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• pp.619-633
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• 1996

Intraseasonal variability of the tropical convection over the Indian/western Pacific is studied using the Geostationary Meteorological Satellite high cloud amount. This study is directed to find the tropical-extratropical interaction in the frequency range of intraseasonal and interannual variabilities of the summer monsoon occured over the domain of 90E-171W and 495-50N. Especially, in order to investigate the intraseasonal interaction of last Asia summer monsoon associated with the tropical convections in the high cloud amounts, the spatial and time structure of the intraseasonal oscillation for the movement-and the evolution of the large-scale connections are studied. To describe the spatial and the time evolution, the extended empirical orthogonal function analysis is applied. The first mode may be considered to a normal structure, indicating that the strong convection band over 90E-120E is extended to sastward but this mode was detected as the intraseasonal variability during summer monsoon. It is found that the dominant intraseasonal mode of the tropical convection consists of the spatial changes over a broad period range centered around 40~50days.

• Proceedings of KOSOMES biannual meeting
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• 2007.11a
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• pp.57-60
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• 2007

The Han River is divided into North and South Korea by NLL(Northern Limit Line) and its area has been blocked by CCL(Civil Control Line) since the Korean War in 1950. Satellite remote sensing, therefore, is uniquely suited to monitoring bar transformation in the region. In river with bar, the characteristics of its physical conditions have a close relationship with bar morphology. In this paper, a monitoring approach of bar transformation in the Han River Estuary is presented using RADARSAT/SAR images from 2000 to 2005 and spatial patterns of bar morphology are presented. It could be said that in the estuary vegetated area and natural levees are developed well, but bars are shifted after an event like a flood. It is also showed that suspended solids such as silt transported through the estuary could contribute highly to a sedimentation environment around Incheon.

• The Korean Journal of Applied Statistics
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• v.26 no.3
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• pp.413-420
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• 2013

Stochastic weather generator is a commonly used tool to simulate daily weather time series. Recently, a generalized linear model(GLM) has been proposed as a convenient approach to tting these weather generators. In the present paper, a stochastic weather generator is considered to model the time series of daily temperatures for Seoul South Korea. As a covariate, precipitation occurrence is introduced to a relate short-term predictor to short-term predictands. One of the limitations of stochastic weather generators is a marked tendency to underestimate the observed interannual variance of monthly, seasonal, or annual total precipitation. To reduce this phenomenon, we incorporate a time series of seasonal mean temperatures in the GLM weather generator as a covariate.

• Journal of Korean Society for Atmospheric Environment
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• v.16 no.6
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• pp.607-623
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• 2000

Major trends of ozone concentration variations in Korea were investigated by using observation data from around 100 stations for the period of 1991∼1997. In addition, important regulating those variations were inferred. Three measures such as the number of days exceeding 80ppb, the 95th percentile of daily maxima, and the annual average concentration were used for the analysis of multi-scale ozone concentration variations. Three areas in the southwest (Sosan, Mokpo, and Cheju) of which monitoring has been operated since 1995 showed the highest annual average concentrations over; this was noted because of the high annual average in the Yosu area in the early 1990s. Large increases in annual average concentrations were observed along the relatively cleaner areas connecting Kangnung and Kwangju(northeast to southwest), in contrast to polluted areas connecting Seoul and Pusan(northeast to southeast). Both the number of exceedance days and the daily maximum concentration were nearly constant in the Greater Seoul Area in spite of interannual flucturations associated with year-to-year changes in air temperature. Within the Greater Seoul Area, all three measures usually showed the same trend; they decreased in the middle and west and increased in the east and northeast. All three measures including the number of exceedance days increased largely at Sillim where the average concentration was high but no exceedance days were recorded in the early 1999s, Nationwide ozone concentration variations appear to be determined by the competitive influence of long-range transport and local urban emissions, Within the city including the Greater Seoul Area, changes in emission which accompany changes in population and in the number if vehicles ( in the process of urban development) were found to be important components of ozone concentration variations.

• Korean Journal of Environment and Ecology
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• v.29 no.1
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• pp.29-45
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• 2015

Water chemistry and fish community, based on fish compositions and ecological characteristics(trophic/tolerance guilds and condition factor), were compared in Gucheon Reservoir($G_cR$) and Yeoncho Reservoir($Y_cR$). Chemical parameters of water quality such as BOD, COD, nutrient(N, P) and suspended solids indicated that water quality was better in the $Y_cR$ than $G_cR$, and the temporal variability in seasonal and interannual patterns were greater in the $Y_cR$. The greater variability was mainly attributed to intense dilutions of reservoir water by Asian monsoon rain during July-August. Fish guild analysis indicated that species diversity was higher in the $G_cR$ than the $Y_cR$, and that the proportion of tolerant and omnivore species were greater in the $Y_cR$. Regression analysis of body weight-total length showed that the regression coefficient(b value) was lower in the $G_cR$(2.15 ~ 2.40) than the $Y_cR$(2.59 ~ 3.14). Condition factor(K) of fish against the total length showed negative slope of Zacco temminckii, Carassius auratus, Pseudorasbora parva and Rhinogobius brunneus population in the $G_cR$, and a positive slope of Carassius auratus and Rhinogobius brunneus population in $Y_cR$. Overall, our data suggest that the growth of the fish populations, based on the length-weight relations and condition factor, reflected the trophic regime of nutrients and organic matter.

• Korean Journal of Agricultural and Forest Meteorology
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• v.6 no.4
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• pp.235-241
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• 2004

There is a growing concern about the possible increase in inter-annual variation of minimum temperature during the winter season in Korea. This view is strengthened by frequently reported freezing injury to dormant fruit trees, while warmer winters have prevailed recently. The January minimum temperature record at fourteen weather stations was analyzed for 1951-2000. The results showed no evidence of increasing standard deviation at 3 locations between 1951-1980 and 1971-2000, while the remaining 11 stations showed a trend of decreasing standard deviation for the two periods. An empirical model explaining the spatial variation of the standard deviation was derived by regression analysis of 56 stations' data for 1971-2000. Daily minimum temperature and the site elevation may account for 68% of the observed variations. We applied this model to restore the average standard deviation of the January minimum temperature for 1971-2000, and the result was used to produce gridded minimum temperature data for the recurrence interval of 10 and 30 years at 250m resolution. A digital form of the plant hardiness zone map may be developed from this product for site-specific selection of adapted plant species.

• Proceedings of the Korea Water Resources Association Conference
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• 2018.05a
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• pp.192-192
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• 2018

토양수분량은 가뭄, 홍수 및 갈수 예보, 유출 해석, 작물의 소비수량 산정과 같이 국가 물 관리 및 수자원 계획 및 개발 등의 목적으로 활용되고 있다. 또한, 생태수문학의 중요한 인자로써 식생의 성장 및 변동의 원인과 결과를 동시에 제공한다. 이는 대기의 상호작용 및 총체적인 물 수지와 관련되며 지표면의 침투, 증발산, 오염물의 이송 및 생태계에도 중요한 인자로 활용된다. 토양수분량은 수자원 부존량에 차지하는 비중은 매우 적지만 대상유역의 유출기구 특성을 지배하는 주요인자로 작용하여 홍수량의 규모에 크게 영향을 미친다. 미국 등 여러 선진 외국에서는 오래 전부터 토양수분에 대한 이론적인 개념을 정립하여 토양수분량을 정기적으로 관측해 오고 있다. 우리나라 또한 토양수분량 관측을 하고 있으며, 주로 농업목적으로 토양수분량 관측소가 운영되고 있다. 그 중 기상청에서는 주로 농업기상관측 항목에 포함하여 농업기상관측소를 운영하고 있으며, 농촌진흥청에서는 농작물의 생육 목적으로 토양수분량 자료를 관측하고 있다. 하지만, 유역 단위의 가뭄과 물 순환을 규명하기 위한 연구가 부족하여 최근 국토교통부에서는 유역 단위의 토양수분량 자료생산 연구를 계획하고 있다. 유역 단위의 토양수분관측의 어려움은 주로 산지에서 발생하는 토양수분의 변동이다. 이는 사면의 유출과 식생의 영향 및 기반암의 영향을 받기 때문이다. 본 연구에서는 청미천(수레의산)과 설마천(감악산) 산지 사면에 설치된 유전율식(TDR, Time Domain Reflectometer)장비로 관측된 최근 3년간(2015~2017)의 데이터를 이용하여 경년변화특성을 분석하였다. 분석 결과는 유역의 물 순환을 규명하는데 가장 중요한 연구로써 활용될 것으로 기대된다.