• 한국환경과학회지
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• 제26권3호
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• pp.289-302
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• 2017

During the research period, error analysis of the amount of daily precipitation was performed with data obtained from 2DVD, Parsivel, and AWS, and from the results, 79 days were selected as research days. According to the results of a synoptic meteorological analysis, these days were classified into 'LP type, CF type, HE type, and TY type'. The dates showing the maximum daily precipitation amount and precipitation intensity were 'HE type and CF type', which were found to be attributed to atmospheric instability causing strong ascending flow, and leading to strong precipitation events. Of the 79 days, most days were found to be of the LP type. On July 27, 2011 the daily precipitation amount in the Korean Peninsula reached over 80 mm (HE type). The leading edge of the Northern Pacific high pressure was located over the Korean Peninsula with unstable atmospheric conditions and inflow of air with high temperature and high humidity caused ascending flow, 120 mm/h with an average precipitation intensity of over 9.57 mm/h. Considering these characteristics, precipitation in these sample dates could be classified into the convective rain type. The results of a precipitation scale distribution analysis showed that most precipitation were between 0.4-5.0 mm, and 'Rain' size precipitation was observed in most areas. On July 9, 2011, the daily precipitation amount was recorded to be over 80 mm (CF type) at the rainy season front (Jangma front) spreading across the middle Korean Peninsular. Inflow of air with high temperature and high humidity created unstable atmospheric conditions under which strong ascending air currents formed and led to convective rain type precipitation.

• 대기
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• 제20권2호
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• pp.111-130
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• 2010

An uncertainty assessment for precipitation datasets simulated by Atmosphere-Ocean Coupled General Circulation Model (AOGCM) is conducted to provide reliable climate scenario over East Asia. Most of results overestimate precipitation compared to the observational data (wet bias) in spring-fall-winter, while they underestimate precipitation (dry bias) in summer in East Asia. Higher spatial resolution model shows better performances in simulation of precipitation. To assess the uncertainty of spatiotemporal precipitation in East Asia, the cyclostationary empirical orthogonal function (CSEOF) analysis is applied. An annual cycle of precipitation obtained from the CSEOF analysis accounts for the biggest variability in its total variability. A comparison between annual cycles of observed and modeled precipitation anomalies shows distinct differences: 1) positive precipitation anomalies of the multi-model ensemble (MME) for 20 models (thereafter MME20) in summer locate toward the north compared to the observational data so that it cannot explain summer monsoon rainfalls across Korea and Japan. 2) The onset of summer monsoon in MME20 in Korean peninsula starts earlier than observed one. These differences show the uncertainty of modeled precipitation. Also the comparison provides the criteria of annual cycle and correlation between modeled and observational data which helps to select best models and generate a new MME, which is better than the MME20. The spatiotemporal deviation of precipitation is significantly associated with lower-level circulations. In particular, lower-level moisture transports from the warm pool of the western Pacific and corresponding moisture convergence significantly are strongly associated with summer rainfalls. These lower-level circulations physically consistent with precipitation give insight into description of the reason in the monsoon of East Asia why behaviors of individually modeled precipitation differ from that of observation.

• 한국수자원학회논문집
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• 제35권1호
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• pp.109-124
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• 2002

본 연구는 간헐 수문사상인 시간강수계열의 구조적 특성을 고찰하여 강수발생의 군집성을 고려한 강수발생과정에 대한 추계학적 모의발생 모형을 개발한 것이다. 먼저 강수사상의 발생패턴을 기술하기 위해 Poisson 군집과정을 사용하였고, 이 과정에서 군집간의 시간과 군집내의 사상 수는 지수분포로 기술하였다. 둘째로 사상의 지속기간과 군집내에서 사상간의 시간은 음대수혼합분포로 기술하였다. 마지막으로 이상과 같은 시간강수사상의 발생패턴과 사상기간내의 강수의 종속구조를 구명하기 위해 서울을 대상으로 하여 실적강수자료를 분석하였다. Monte Carlo 모의결과는 모형이 강수발생의 계절적 패턴, 사상특성의 주변 및 조건부 분포를 잘 재현하고 있음을 보여주었다.

• 한국수자원학회논문집
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• 제35권6호
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• pp.763-777
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• 2002

본 연구의 목적은 간헐 수문사상인 시간강수계열의 구조적 특성을 고찰하여 강수량 모의발생을 위한 추계학적 모형을 개발하는 것이다. 이를 위하여 본 연구에서는 강수발생과정에 대한 추계학적 모형은 이재준과 이정식(2002)이 개발한 추계학적 모형을 이용하였으며, 강수량과정을 위하여 사상내의 시간강수량을 비정상 1차 자기회귀모형으로 기술하였다. 시간강수계열의 강수발생과정과 강수량과정을 조합하면 시간강수사상의 발생패턴과 사상기간내의 강수의 종속구조를 모의할 수 있는 시간강수계열에 대한 모의모형이 얻어지며, 이 모형의 적합성을 구명하기 위해 서울을 대상으로 하여 실적강수자료를 분석하였다. Monte Carlo 모의결과는 모형이 사상기간내의 강수강도, 지속 기간, 크기의 주변 및 조건부 분포를 잘 재현하고 있음을 보여주었다. 실적 및 모의 자료에 대한 자기상관함수도 비교적 작은 시간지체에서는 유사하였다

• 한국방재학회 논문집
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• 제9권5호
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• pp.103-113
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• 2009

본 연구에서는 관측소의 지리적 위치 및 강수특성(월별, 계절별, 연평균)을 이용하여 강원도의 강수지역을 구분하였다. 강수지역 구분은 기상관측소 66개소(기상관서: 11개소, 자동기상시스템(AWS): 55개소)의 자료를 이용하였으며, 통계적 방법 중 군집 기법인 K-means 방법을 적용하였다. 지역구분 결과, 강수지역은 5개 지역(영동지방 1개 지역 및 영서지방 4개 지역)으로 구분하였다. 계절별 평균강수량은 봄에는 강원도 전체에 유사하게 발생하였으며, 여름에는 영서지방이 높게 나타났으며, 가을과 겨울에는 영동지방이 높게 발생하였다. 연평균 강수량 및 여름철 강수량의 공간분석 결과 강원도 중 일부 지역(미시령 및 대관령일원)은 산악형 강수 특성을 나타냈으나 전반적인 현상은 아닌 것으로 판단되었다. 그러나 보다 정확한 분석을 위해서는 관측소의 고도별 분포가 미흡한 것으로 나타난 관측소의 보완 및 AWS의 자료 확충이 필요할 것으로 판단된다.

• 대기
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• 제32권2호
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• pp.135-148
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• 2022

This study investigates the influence of atmospheric river (AR) on precipitation over South Korea with a focus on regional characteristics. The 42-year-long catalog of ARs, which is obtained by applying the automatic AR detection algorithm to ERA5 reanalysis data and the insitu precipitation data recorded at 56 weather stations across the country are used to quantify their relationship. Approximately 51% of the climatological annual precipitation is associated with AR. The AR-related precipitation is most pronounced in summer by approximately 58%, while only limited fraction of precipitation (26%) is AR-related in winter. The heavy precipitation (> 30 mm day^-1) is more prone to AR activity (59%) than weak precipitation (5~30 mm day^-1; 33%) in all seasons. By grouping weather stations into the four sub-regions based on orography, it is found that the contribution of AR precipitation to the total is largest in the southern coast (57%) and smallest in the eastern coast (36%). Similar regional variations in AR precipitation fractions also occur in weak precipitation events. The regional contrast between the northern and southern stations is related to the seasonal variation of AR-frequency. In addition, the regional contrast between the western and eastern stations is partly modulated by the orographic forcing. The fractional contribution of AR to heavy precipitation exceeds 50% in all seasons, but this is true only in summer along the eastern coast. This result indicates that ARs play a critical role in heavy precipitation in South Korea, thus routine monitoring of ARs is needed for improving operational hydrometeorological forecasting.

• Journal of Ecology and Environment
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• 제42권2호
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• pp.77-84
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• 2018

Background: For understanding and evaluating a more realistic and accurate assessment of ecosystem carbon balance related with environmental change or difference, it is necessary to analyze the various interrelationships between soil respiration and environmental factors. However, the soil temperature is mainly used for gap filling and estimation of soil respiration (Rs) under environmental change. Under the fact that changes in precipitation patterns due to climate change are expected, the effects of soil moisture content (SMC) on soil respiration have not been well studied relative to soil temperature. In this study, we attempt to analyze relationship between precipitation and soil respiration in temperate deciduous broad-leaved forest for 2 years in Gwangneung. Results: The average soil temperature (Ts) measured at a depth of 5 cm during the full study period was $12.0^{\circ}C$. The minimum value for monthly Ts was $-0.4^{\circ}C$ in February 2015 and $2.0^{\circ}C$ in January 2016. The maximum monthly Ts was $23.6^{\circ}C$ in August in both years. In 2015, annual precipitation was 823.4 mm and it was 1003.8 mm in 2016. The amount of precipitation increased by 21.9% in 2016 compared to 2015, but in 2015, it rained for 8 days more than in 2016. In 2015, the pattern of low precipitation was continuously shown, and there was a long dry period as well as a period of concentrated precipitation in 2016. 473.7 mm of precipitation, which accounted for about 51.8% of the precipitation during study period, was concentrated during summer (June to August) in 2016. The maximum values of daily Rs in both years were observed on the day when precipitation of 20 mm or more. From this, the maximum Rs value in 2015 was $784.3mg\;CO_2\;m^{-2}\;h^{-1}$ in July when 26.8 mm of daily precipitation was measured. The maximum was $913.6mg\;CO_2\;m^{-2}\;h^{-1}$ in August in 2016, when 23.8 mm of daily precipitation was measured. Rs on a rainy day was 1.5~1.6 times higher than it without precipitation. Consequently, the annual Rs in 2016 was about 12% higher than it was in 2015. It was shown a result of a 14% increase in summer precipitation from 2015. Conclusions: In this study, it was concluded that the precipitation pattern has a great effect on soil respiration. We confirmed that short-term but intense precipitation suppressed soil respiration due to a rapid increase in soil moisture, while sustained and adequate precipitation activated Rs. In especially, it is very important role on Rs in potential activating period such as summer high temperature season. Therefore, the accuracy of the calculated values by functional equation can be improved by considering the precipitation in addition to the soil temperature applied as the main factor for long-term prediction of soil respiration. In addition to this, we believe that the accuracy can be further improved by introducing an estimation equation based on seasonal temperature and soil moisture.

• 한국지구과학회지
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• 제27권2호
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• pp.149-158
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• 2006

1973년에서 2001년 남한의 강수자료를 이용하여 계절성 강수에 대하여 연구 분석하였다. 남한 63개 관측지점에 대한 계절성 강수지수와 계절성 강수지수의 연 변화에 대해 조사하였다. 이 연구에서의 계절성 강수라 함은 연중 특정 몇 달에 집중되는 강수의 집중도를 의미한다. 강수 형태는 여러 원인에 의해 변하며, 여름철에는 국지성 강수가 발생한다. 계절성 강수 지수를 이용하여 남한 지역의 계절성 강수 특성을 분석한 결과 남한 지역은 전체적으로 계절성 강수의 특성을 띠고 있는 지역이었으나 1993년 이후 건조한 날씨가 길어지고, 이후 집중호우가 내리는 계절성 강수의 특성이 더욱 뚜렷해지고 있다. 이동평균을 이용하여 계절성 강수 지수의 연 변화를 분석한 결과 남한의 62개 관측지점의 계절성 강수 지수는 29년간 증가하는 추세를 보이고 있음을 확인하였다. 특히 과거($1973{\sim}1982$년)에는 6월, 7월에 집중되던 강수가 최근($1992{\sim}2001$)에는 8월, 9월에 집중되고 있으며, 10월에도 강수가 집중되는 현상을 보이고 있다. 또한 과거($1973{\sim}1982$)에는 계절성 강수 강도 3에 속하는 지역이 많았으나, 1993년 이후부터는 계절성 강수 강도 5와 6에 속하는 관측지점이 늘어나고 있는 추세이다. 계절성 강수 강도 5와 6에 속하는 관측지점이 늘어나고 있다는 것은 남한지역의 강수특성이 건조한 날씨가 계속되다가 이후 특정한 달에 강수가 집중되어 내리는 계절성 강수의 현상이 더욱 뚜렷해지고 있다는 것을 보여주고 있다.

• 한국대기환경학회지
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• 제20권3호
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• pp.381-396
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• 2004

In order to understand the precipitation acidity and chemical composition of ion species in Iksan area as well as to know the difference of chemical characteristics in precipitation samples from the viewpoint of precipitation sampling method, precipitation samples were collected by wet-only automatic precipitation sampler and bulk manual precipitation sampler in Iksan, from March 2003 to August 2003. The mean pH of precipitation was 5.0. There was a little significant difference in the mean value of pH between automatic and manual sampler. However, pH values of some precipitation samples were lower in automatic sampler than in manual sampler, especially in case of precipitation samples with small rainfall for March 2003. The mean concentrations of each ions in precipitation were generally a little higher in precipitation samples collected by the manual sampler than in those collected by the automatic sampler because of accumulation of dry deposition on the surface of glass funnel installed at the manual sampler during the sampling period or no rainfall. Dominant species determining the acidity of precipitation, were N $H_4$$^{[-10]}$ and nss-C $a^{2+}$ for cations and nss-S $O_4$$^{2-}$ and N $O_3$$^{[-10]}$ for anions. The mean concentration of N $H_4$$^{+}$ and nss-C $a^{2+}$ were 31 $\mu$eq/L and 9 $\mu$eq/L for the automatic sampler and 40 ueq/L and 16 ueq/L for the manual sampler, respectively. In addition, nss-S $O_4$$^{2-}$ and N $O_3$$^{[-10]}$ were 27 $\mu$eq/L and 13 $\mu$eq/L for the automatic sampler and 32 $\mu$eq/L and 17 $\mu$eq/L for the manual sampler, respectively. Although the concentrations of the acidifying ions of nss-S $O_4$$^{2-}$ and N $O_3$$^{[-10]}$ were about 3 times higher than those for foreign pristine sites, precipitation acidity were estimated to be natural due to the neutralization reaction of the alkaline species of N $H_4$$^{+}$ and nss-C $a^{2+}$ with its higher concentrations. Considering the ratios of nss-S $O_4$$^{2-}$/N $O_4$$^{[-10]}$ nss-S $O_4$$^{2-}$, it was found that ammonium sulphate was dominant in Iksan precipitation. The major non-sea salt ions were maximum concentrations for March, but decreased with increasing of precipitation amount.on amount.

• 한국지구과학회지
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• 제44권6호
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• pp.557-577
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• 2023

본 연구에서는 레이더 관측 영역 내에 강수 에코(echo)가 없는 지역을 비강수 정보라고 정의하고 자료 동화에 활용하였다. 비강수 정보는 레이더로 관측할 수 있는 최대 영역 내에서 강수에 의한 에코가 나타나지 않고 레이더에서 관측할 수 없을 정도로 약한 강수나 구름 입자가 있거나, 강수 자체가 없다는 것을 의미한다. 기존의 레이더 자료를 동화한 연구가 강수에 의한 반사도와 시선속도를 동화하여 모델 내의 강수를 만들어내는 것에 초점을 두었다면, 본 연구에서는 에코가 없다는 것도 하나의 정보로 고려하고 이를 동화함으로써 모델 내에서 잘못 예측한 강수를 억제하였다. 비강수 정보를 자료동화에 적용시키기 위해 레이더 비강수 정보를 수상체와 상대습도로 변환하는 관측 연산자를 제시하고 이를 Weather Research and Forecasting (WRF) 모델의 자료동화 시스템인 WRF Data Assimilation system (WRFDA)에 적용하였다. 또한 비강수 정보를 효과적으로 활용하기 위한 레이더 자료의 처리 방법을 제시하였다. 비강수 정보가 모델 내에서 잘못 예측한 강수를 억제할 수 있는지 확인하기 위해 단일 관측실험을 수행하였으며 비강수 정보가 수상체와 습도 그리고 기온을 낮춤으로써 대류가 억제될 수 있는 환경을 만들었다. 비강수 정보의 동화 효과를 실제 사례에 적용한 2013년 7월 23일 대류 사례 실험을 통해 9시간 예측을 수행하여 결과를 분석하였다. 레이더 비강수 정보를 추가로 동화한 실험이 비강수 정보를 제외한 실험보다 Fractional Skill Score (FSS)가 증가하고 False Alarm Ratio (FAR)는 감소하여 모델의 강수 예측성을 향상시켰다.