• Korean Journal of Soil Science and Fertilizer
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• v.47 no.1
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• pp.48-58
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• 2014

In order to evaluate water balance at upland according to RCP8.5 climate change scenario distributed by Korean Meteorological Administration (KMA), we simulated soil moisture using estimation model, called AFKAE0.5 for 66 sites from 2011 to 2020, and established the water balance maps. The amount of annual average precipitation by RCP8.5 scenario was highest in 2016 as recorded 2,062 mm and lowest in 2011 with 1,134 mm. As result of analysis for monthly precipitation and runoff, the amounts of precipitation and runoff have been especially intensive in July in 2014, 2016, 2019, and 2020. Overall, the area of Kyeongbuk and Gyeonggi was estimated more dried status of soil compared with precipitation. Except 2015 and 2020, soil water balance was recorded as negative value in other years which was calculated by subtracting output from input. The status of soil moisture was the most dry in 2020 among those in other years.

• Journal of Korea Water Resources Association
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• v.31 no.6
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• pp.807-819
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• 1998

The relationships of El Nino and La Nina with both temperature and precipitation in South Korea is studied. Monthly temperature and precipitation are analyzed using harmonic analysis to identify region, magnitude and season that have responses associated with El Nino and La Nina. The first harmonic is extracted from a 24 month El Nino and La Nina composite at each station. The regions are identified by the similarity in the phase of the harmonic vectors. The responses of precipitation to El Nino and La Nina are found in the all regions. However, the response of precipitation to El Nino and La Nina is identified only in the southern region. In addition, statistical significance for response periods is investigated through cross correlation analysis. Once an El Nino and a La Nina event set in, the results of this analysis can provide an efficient information for the management of water resources, agriculture and environment.

• Proceedings of the KSRS Conference
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• 2002.10a
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• pp.366-366
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• 2002

Cloud-to ground lightning and total precipitation over Korean peninsula during the summer monsoon season are studied extensively with a special emphasis on the characteristics of convective precipitation. Ten years (1988-1997) lightning and rainfall data and a temporal and spatial scale of one month and 10$^2$ km$^2$ respectively are used to calculate the monthly number of CG lightning flash count. Monsoonal convective activity is higher over the west coast with maxima at two different regions, one in the northern part which increases nortwestward and the other is at the middle west coast of Korea increasing towards the west coast. East coast represents the minimum value of monsoonal convective activity. In the east coast of Korean peninsula, particularly in the region east of Tae-back mountain, the value of Rain yield, (which is defined as the ratio of total precipitation to CG flash count over a common area), is maximum with an average value of 3$\times$10$^{8}$ kg fl$^{-1}$, while the minimum value of rain yield is occurred in the west of Tae-back mountain, with an average value of 0.8$\times$10$^{8}$ kg fl$^{-1}$. Results show in the west coast stations, nearly 82% of the total rainfall is convective in nature, at the middle of the peninsula 53% of the total rain is convective while in the east coast stations 46% contribution from the convective rain is seen. Kanghwa receives the maximum convective rain while at Ulsan the convective rain is minimum. Correlation coefficient between the total precipitation and CG lightning during the summer monsoon season is 0.54.

• The Journal of Engineering Geology
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• v.33 no.2
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• pp.241-256
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• 2023

Long-term droughts and frequent spring droughts are causing damage to crops, which are the means of livelihood of residents of the Yeoncheon region. To analyze the degree of drought in Yeoncheon, the ratio of monthly precipitation and discharge was reviewed through observed data, and the standardized precipitation index and streamflow drought index were calculated. As a result of drought analysis using precipitation and discharge observation stations near the Yeoncheon basin, it was analyzed that the drought that occurred in 2014 was common to all drought indices and that drought occurred continuously until 2019, either large or small. In the case of drought indices with a duration of 12 months, it is expected that the damage caused by the drought would be severe as the drought period lasted 24 months. In order to manage drought damage, it is important to understand and predict the current state of drought. In order to cope with drought in advance, it is urgent to implement an integrated operation management strategy for rivers and waterworks structures according to the degree and duration of drought.

• The Korean Journal of Applied Statistics
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• v.5 no.2
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• pp.123-137
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• 1992

We analyzed a time series composed of the annual precipitations of Seoul based on the measurements of a Korean raingage and a modern raingage. The precipitations measured with a Korean raingage for the period of 1771 to 1907 are followed by the precipitations with a modern raingage for the period of 1908 to 1990. The latter part of the time series of annual precipitations were obtained from a book for annual precipitations of Korea by Korea Meteorological Administration and the former from Wada's table 1 for monthly precipitations reproduced from the daily rainfall measurements by a Korean raingage for the period of the Yi Dynasty. In our analysis three different precipitation regimes clearly stand out of the entire period. In order to define objectively the period of each precipitation regime we made a time series of 9 year moving averages from the above time series. By taking into account the shapes of the moving average time series and by using a threshold value of annual precipitation 1050 mm, we defined three precipitation regimes of wet period 1(WP1), dry period (DP), and wet period 2 (WP2). The WP1 and WP2 show very similar characteristics in out statistical analyses. On the other hand, DP is very different from the two periods in many statistical aspects. The strong similarities of the WP1 and WP2 regimes in the magnitudes of statistical parameters and in the shapes of their power spectrum distribution are supporting very positively the soundness of precipitation amounts measured with a Korean raingage in spite of numerous conceivable errors which might have been introduced into measurements of precipitation due to changes of observation site and environment, the scale of units employed, and urbanization of Seoul, etc. However, the annual precipitation amounts are not enough to examine throughly the characteristic of precipitation variations during the two regimes. It is definitely necessarly to recover the daily amounts of precipitation, based on two or three times measurements of rainfall with a Korean raingage, scattered in various ancient documents such as the official diary of 'Seungjeong-weon'

• Water for future
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• v.17 no.2
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• pp.125-131
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• 1984

watershed Model by mathematical formulation is one of the powerful tool to analyze the hydrologic process in a watershed. The seasonal watershed model is one of the mathematial model from which the monthly streamflow can be simulated and forcasted for given precipitaion data. This model also enables us to compute the monthly runoff at each subbgasin when the basin is subdivided into several small subbasins. The computation of runoff volume makes a Prediction of the areal distirbution of runoff volume for a given precipitation data. Several basins in Han River basin were chosen to simulate the monthly runoff and compute the runoff at each subbasin. A simple logarithmic regression were conducted between runoff ratio and area ratio. The correlation was very high and the equation can be used for prediciting flood volume when flood at downstream gaging station is know.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.13 no.3
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• pp.36-45
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• 2010

To analyze the relationship between climatic factors (monthly mean temperature and total precipitation) and tree-ring growths of Quercus mongolica Fischer (Mongolian oak) with different topographic sites in Mt. Worak, more than 10 trees were selected from each of seven stands. Two cores from each tree were measured for ring width. After crossdating, each ring-width series was double standardized by fitting first a negative exponential or straight regression line and secondly a 60-year cubic spline. Seven stands were categorized in two groups using cluster analysis for tree-ring index patterns. Cluster I (four stands) was located in higher elevation (550-812 m) with aspects of east, west and northwest, and cluster II (three stands) was located in rather lower election (330-628 m) with aspects of north and northwest. The aspects of two clusters were not significantly different. Response-function analysis showed a significant positive response to March precipitation for both clusters. It indicates that moisture supply during early spring season is important to radial growth because the cambial growths of ring-porous species, such as Mongolian oak, start before leaf growth. Cluster II showed a positive response to the precipitation of middle and late growing season, too.

• Water for future
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• v.8 no.2
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• pp.81-92
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• 1975

Calculation of the monthly water balance for Nakdong River basin for the period from 1958 to 1968 is made by determining three components independently: precipitation, runoff and evapotranspiration. The areal precipitation is computed by the Thiessen method using the records of nine meteorological stations in the basin, and the runoff is the flow gauged at Jindong which is located on the most downstream. For the computation of evapotranspiration, the Morton method is adopted because this method is relatively fit best in the calculation of water balance among the Morton, Penman and Thornthwaite methods. The values of Morton evapotransp iration are corrected by the factor of 0.82 in the basin in order to bring the error to zero. The areal evapotranspiration is the arithmetic mean of the Morton estimates at the stations. Mean water balance components in the Nakdong river basin are 1117.0mm, 600.6mm and 516.4m for precipitation, runoff and evapotranspiration respectively. Accordingly, the mean runoff ratio comes out to be 0.54. The smallest values of runoff coefficient are due for Daegu area, while the largest ones are for the southwest of the basin with the higher rainfall and high elevations there. The amount of runoff obtained by both Thornthwaite and Budyko methods for water balance computations indicate 59 and 60 per cent of actual values which are lower than the expected. An attempt is made to find the best reliable rainfall-runoff relation among the four methods proposed by Schreiber, 01'dekop, Budyko and Sellers. The modified equation of Schreiber type for annual runoff coefficient could be obtained with the smallest mean error of 11 per cent.

• The Korean Journal of Applied Statistics
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• v.21 no.3
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• pp.547-560
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• 2008

It is well known that spectral density function determines auto-covariance function of stationary time-series data and smoothed periodogram is a consistent estimator of spectral density function. Recently, Kim and Park (2007) showed that smoothed- periodogram based distances performs very well for the classification. In this paper, we introduce classification methods with smoothed periodogram and apply the approaches to the monthly precipitation measurements obtained from January, 1987 through December, 2007 at 22 locations in South Korea.

• Atmosphere
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• v.18 no.4
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• pp.249-266
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• 2008

The tendencies for teleconnection with a time lag and other characteristics of Korean summer droughts have been investigated and some clues to predict the drought occurrences several months before have been found. First, the May and June droughts in Korea are simultaneous with those over the northwestern part of Korea owing to the relation with the baroclinic wave. However, the July and August droughts occur over the mid-latitudes or southern part of Korea owing to the relation with the Changma front. Second, several months before the MJJA droughts in Korea, it is found that the effective drought index (EDI) over particular areas (hereafter, referred to as the omen areas) is large. Thailand, Carolina Island, Mongolia, and Central Bengal Bay were selected as the omen areas. Third, when the monthly minimum EDI (MME) of the omen area in winter is more than 0.7, it signifies that the precipitation is above normal, Korea has almost always experienced a summer drought. However, the droughts occurring with this type of relationship only represent half of the MJJA droughts in Korea. Fourth, the relationships between the Korean drought and the precipitation over omen areas in low latitudes are not valid over all the eight precipitation areas in Korea, but only over Areas I, II, and III, where heavy rains occur during spring and summer.