• Journal of the Korean earth science society
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• v.28 no.1
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• pp.35-44
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• 2007

This paper investigated the relationship between El $Ni\widetilde{n}o-Southern$ Oscillation (ENSO) and Indian Ocean Dipole (IOD) mode events and the impacts of these two phenomena on the climate, temperature and precipitation, of the Korean Peninsula. Data gathered from 1954 to 2004 were used for analysis, which included NINO 3 index, IOD index, and monthly mean precipitation and temperature at eleven locations in Korea. Statistical results showed that the IOD and ENSO were significantly correlated in Spring and Fall. It was clearly shown that the distribution of the sea surface temperature in the Indian Ocean has seen the Southern and Northern Oscillation in El $Ni\widetilde{n}o$ year, and Eastern and Western in IOD year. On the other hand, in El $Ni\widetilde{n}o$ you, the mean temperature of the Korea Peninsula was lower than normal in Summer and higher in Winter and its precipitation was more than normal in both Summer and Winter. However, significant correlation was not found in IOD year. In addition, the global atmospheric circulations during the major IOD years are less influential, unlike those of El $Ni\widetilde{n}o$ events.

• Journal of Environmental Science International
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• v.22 no.5
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• pp.625-638
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• 2013

Recently, the occurrences of droughts have been increased because of global warming and climate change. Water resources that mostly rely on groundwater are particularly vulnerable to the impact of precipitation variation, one of the major elements of climate change, are very sensitive to changes in the seasonal distribution as well as the average annual change in the viewpoint of agricultural activity. In this study, the status of drought for the present and future on Jeju Island which entirely rely on groundwater using SPI and PDSI were analyzed considering regional distribution of crops in terms of land use and fluctuation of water demand. The results showed that the precipitation distribution in Jeju Island is changed in intensity as well as seasonal variation of extreme events and the amount increase of precipitation during the dry season in the spring and fall indicated that agricultural water demand and supply policies would be considered by regional characteristics, especially the western region with largest market garden crops. Regarding the simulated future drought, the drought would be mitigated in the SPI method because of considering total rainfall only excluding intensity variation, while more intensified in the PDSI because it considers the evapotranspiration as well as rainfall as time passed. Moreover, the drought in the northern and western regions is getting worse than in the southern region so that the establishment of regional customized policies for water supply in Jeju Island is needed.

• Journal of Soil and Groundwater Environment
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• v.25 no.4
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• pp.14-27
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• 2020

The drought has occurred from the past, and has caused a lot of damage. It is important to analyze the past droughts and predict them in the future. In this study, the temperature and precipitation of the past and the future from climate change RCP 4.5 and 8.5 scenarios were analyzed for Seosan and Boryeong in the western region of Chungnam Province, which is considered as a drought-prone area on the Korean Peninsula. Comparing Standardized Precipitation Index (SPI) and Effective Drought Index (EDI) based on the past droughts, EDI was verified to be more suitable for the drought assessment. According to RCP 4.5, the frequency and intensity of droughts in the early future (2021~2060) were expected to increase and to be stronger. Particularly, severe droughts were predicted for a long time from 2022 to 2026, and from 2032 to 2039. Droughts were expected to decrease in the late future (2061~2100). From RCP 8.5, drought occurrences were predicted to increase, but the intensity of the droughts were expected to decrease in the future. As a result of evaluation of the frequencies of droughts by seasons, the region would be most affected by fall drought in the early future and by spring drought in the late future according to RCP 4.5. In the case of RCP 8.5, the seasonal effects were not clearly distinguished. These results suggest that droughts in the future do not have any tendency, but continue to occurr as in the past. Therefore, the measures and efforts to secure water resources and reinforcement of water supply facilities should be prepared to cope with droughts.

• The Korean Journal of Quaternary Research
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• v.14 no.2
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• pp.117-123
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• 2000

This study examined the spatial distribution of precipitation in Sokcho area. The hourly, daily and monthly precipitation on the 2 stations, 5 AWS in Sokcho area were analyzed by daily, monthly, altitudinal distribution and synoptic environment. The results of the Study are as follows. The amount of Yearly precipitation, 1970~1999 in Sokcho area is gradually increasing. The amount of monthly precipitation 1970~1999 at Sorak weather observation station (altitude 148m), Compared with that in 7 Stations is greatest in spring, Summer and autumn. Because the valleys near Ssangcheon river are funnels for sea wind into Sorak weather observation station. The amount of Summerly precipitation at Mishiryong(1993~1999), the highest altitude in 7 weather observations stations is more 95.2mm than that of Sokcho airport, the lowest altitude, but the amount of winterly precipitation at Sokcho airport is more 89.6mm than that of Mishiryong. When the heavy rainfall and the heavy Snowfall occured in Sokcho area, wind systems were mainly a sea wind (north-north-eastly wind, north-westly wind) and daily mean wind speed was respectively 4.4㎧, 3.6㎧. The amount of the heavy rainfall and heavy snow fall in Sokcho area is closely associated with the north-eastly stream at the lower and the upper level toward the coast of East sea(Sokcho area).

• Korean Journal of Remote Sensing
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• v.14 no.2
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• pp.165-174
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• 1998

The observation of liquid water content(LWC) and the estimation of precipitation enhancement by cloud seeding were made over the Andong in Korea from March 1997 through Feb 1998. A dual-channel microwave radiometer was used to measure the liquid water content and water vapor. It was shown that the 90% of observational period had the amount of less than 0.1 mm in LWC, and that the amount of precipitation was proportionally increased to liquid water content. The amount of LWC has maximum in summer and minimum in winter. The content of liquid cloud water was showed higher value from the time of 12 to the time of 17 except for summer season in which it extremely fluctuated with a large precipitation. The majority of liquid water content over the area occurred with westerly and southwesterly wind which were flowed from the Sobaek mountain. The ratio of horizontal LWC flux and vertical precipitation flux, $P_{en}$ is almost ranked in the interval of 0.0~0.5 with maximum of 0.5 in spring, 0.2 in summer and fall, and 0.1 in winter. Accordingly, it is estimated that the potential enhancement of precipitation over Andong area by cloud seeding has high value in spring with westerly wind.

• Journal of Climate Change Research
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• v.2 no.2
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• pp.133-141
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• 2011

This study is to identify the trend of climate change in Gangwon-do by examining accumulated climate data such as temperature and precipitation in Gangneung city over the past about 100 years. The annual mean temperature and precipitation in Gangneung have increased by $1.4^{\circ}C$ and 14.7%, respectively, over the last 98 years (1912~2009). The trends of Gangneung showed that precipitation has intensified as the number of precipitation days decreased while its amount increased during the period. Based on the temperature data, spring and summer began earlier whereas the onsets of fall and winter were delayed. Summer has become longer and winter shorter by about a month. Averaging observation data from seven weather stations in Gangwon-do, the annual mean temperature and precipitation have increased by $0.8^{\circ}C$ and 21.0% respectively over the last 37 years (1973~2009). By region, Wonju city recorded the biggest increase of $1.6^{\circ}C$ in the annual mean temperature while Sokcho city the smallest increase of $0.4^{\circ}C$. In the annual mean precipitation, Daegwallweong recorded the biggest change of 22.2% and Wonju city the smallest of 12.0%.

• Journal of Korean Society for Atmospheric Environment
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• v.5 no.2
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• pp.42-54
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• 1989

This study was carried out to investigate the phenomena of acid precipitation. The pH value, electro conductivity and major anions (sulfate, nitrate and chloride) were measured by automatic acid rain monitor and ion chromatography at 5 points in Seoul area from Jan. to Dec. 1988. 1. The acidity of rainfall was in order winter (4.31) spring (4.77) fall (4.94) summer (5.31). Rainfall with a pH of less than 5.6 was appeared 83.2 percent. 2. The range of the highest appearence frequency rate both at Hannam-dong and Songsu-dong was from pH 4.6 to 5.0 and appeared 30.7 percent and 38.3 percent respectively, Bang-i-dong was 36.3 percent in the ranged from pH 4.1 to 4.5 and Guro and Ssangmun-dong were 26 percent and 30.3 percent in the ranged from pH 5.1 to 5.5 respectively. 3. The sulfate and nitrate ion concentration in earlier rainwater ranged from 0.1 ppm to 50.2 ppm and from 0.01 ppm to 15.8 respectively. The earlier rainwaters were generally more acidic than the after rainwaters. 4. The order of the major anion concentration in rainwater was $SO_4^{2-} > Cl^- > NO_3^-$ and the acidity of it was more effective by sulfate ion than others. The correlation between pH value and anions concentration was shown positive correlationship at Guro-dong and Bang-i-dong and negative correlation at Hannam-dong but not at the other sites.

• Atmosphere
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• v.24 no.1
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• pp.77-87
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• 2014

The radar reflectivity is significantly affected by ground clutter, beam blockage, anomalous propagation (AP), birds, insects, chaff, etc. The quality of radar reflectivity is very important in quantitative precipitation estimation. Therefore, Weather Radar Center (WRC) of Korea Meteorological Administration (KMA) employed two quality control algorithms: 1) Open Radar Product Generator (ORPG) and 2) fuzzy quality control algorithm to improve quality of radar reflectivity. In this study, an occurrence of AP echoes and the performance of both quality control algorithms are investigated. Consequently, AP echoes frequently occur during the spring and fall seasons. Moreover, while the ORPG QC algorithm has the merit of removing non-precipitation echoes, such as AP echoes, it also removes weak rain echoes and snow echoes. In contrast, the fuzzy QC algorithm has the advantage of preserving snow echoes and weak rain echoes, but it eliminates the partial area of the contaminated echo, including the AP echoes.

• Korean Journal of Environment and Ecology
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• v.34 no.1
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• pp.55-62
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• 2020

To estimate headwater stream temperature with seasonal variations, we analyzed precipitation, runoff and air temperature in experimental forest of Kangwon National University, Gangwon-do (2017~2018 years). The daily mean value of headwater stream temperature for spring was 6.9~17.7℃ and correlated with air temperature, that for summer and fall were 12.2~26.3℃ and 3.6~19.3℃, correlated with air temperature and runoff. Based on seasonal variations, we applied for stepwise multiple linear regression analyses to estimate headwater stream temperature with seasonal variations. The equations were headwater stream temperature(WT)_spring=(0.553×Air temperature)+(0.086×Runoff)+4.145 (R²=0.505; p<0.01), WT_summer=(0.756×Air temperature)+(-0.072×Runoff)+2.670 (R²=0.510; p<0.01), and WT_fall=(0.738×Air temperature)+(0.028×Precipitation)+2.660 (R²=0.844; p<0.01). The coefficient of determination (R²) was greater than when it was estimated by air temperature in all seasons and progressively increased from spring to winter. Therefore, we indicated difference on estimated magnitude of stepwise multiple linear regression, due to effects on headwater stream temperature of different environmental factors with seasonal variations. Furthermore, temporal factors with spatial characteristics (e.g., river versus headwater stream) could be recommended for estimating headwater stream temperature.

• Journal of the Korean earth science society
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• v.26 no.7
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• pp.732-743
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• 2005

The characteristics of precipitation over South Korea from 1973 to 2002 were investigated. The synoptic patterns inducing precipitation are classified by 10 categories, according to the associated surface map analysis. The annual mean frequency of the total precipitation, its duration time and amount for 30 years are 179 times, 2.9 hours, and 7.1 mm, respectively. About $59\%$ of the total precipitation events were associated with a synoptic low. The dominant patterns are identified with respect to seasons: A synoptic mobile low pressure pattern is frequent in spring, fall, and winter, whereas low pressure embedded within the Changma and orography induced precipitation are dominant in summer and in winter. For the amount of precipitation, precipitation originated from tropical air associated with typhoon, tropical convergence, and Changma is more significant than that with other pressure patterns. The statistical elapse time reaching to 80 mm, which is the threshold amount of heavy rainfall watch at KMA, takes 12.9 hours after the onset of precipitation. The probability distribution function of the precipitation shows that the maximum probability for heavy rainfall is located at the south-coastal region of the Korean peninsula. It is also shown that the geographical distribution of the Korean peninsula plays an important role in occurrence of heavy rainfall. For example, heavy precipitation is frequently occurred at Youngdong area, when typhoon passes along the coastal region of the back borne mountains in the peninsula. The climatological classification of synoptic patterns associated with heavy rainfall over South Korea can be used to provide a guidance to operational forecast of heavy rainfall in KMA.