• 대기
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• 제20권2호
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• pp.91-100
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• 2010

In accordance with the time series of rainfall in summer (June, July and August) in South and North Korea for recent 28 years (1981-2008), rainfall is substantially increased in South Korea since 1996, while it is significantly decreased in North Korea. In particular, the decreasing tendency of rainfall in summer in North Korea is more definitely observed during the $2^{nd}$ rainy season (late August - mid September) in intraseasonal variation. Such a feature is also confirmed in the spatial distribution of oscillation pattern between South and North Korea on the basis of 1996 which is obtained by empirical orthogonal function analysis using the summer rainfall observed in all weather observation stations in South and North Korea. For the decreasing tendency of rainfall in North Korea, it is found that northeasterlies from anticyclonic circulation centered on around Baikal Lake weaken convective activity during summer. On the contrary, the increasing tendency of rainfall in South Korea is related to the strengthened cyclonic circulation in the southern region of China and accordingly, enhances southwesterlies in South Korea.

• 대기
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• 제22권4호
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• pp.401-413
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• 2012

In this study, an investigation has been carried out to understand 1) temporal variation of rainfall amount in summer over south Korea during the 30-year period of 1979-2008 and 2) the relationship between the variation of rainfall amount and the change of large-scale monsoon circulation around 1993/1994 over East Asia. The analysis of rainfall amount is carried out separately for whole summer (June-August), climatological Changma period of 23 June-23 July, and August to consider variations within summer. To relate the variation of rainfall amount with the change of large-scale circulation, we have considered two 15-year periods of 1979-1993 and 1994-2008. This study has used observations at 58 stations in South Korea and NCEP-NCAR $2.5^{\circ}{\times}2.5^{\circ}$ reanalysis data. The major change in synoptic environment for the Changma period is characterized by the intensified anticyclone over Mongolia during 1994-2008, which results in a weak meridional oscillation of Changma front. As a result, rainfall amount for the Changma period and the frequency of extreme events have significantly increased after 1993/1994. A major change of synoptic environment for August is the significant westward extension of the western Pacific subtropical high, which allows not only more moisture transports but also stronger cyclonic circulation over the Korean peninsula. Rainfall amount for August and frequency of extreme events have also increased after 1993/1994. However, variability of rainfall amount is larger for August than that for the Changma period, with some years showing very dry August (monthly rainfall amount less than 150 mm).

• 대한지리학회지
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• 제48권2호
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• pp.184-203
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• 2013

이 연구에서는 장기간의 관측 자료를 이용하여 적도 저주파 진동과 관련된 한반도 여름철 강수의 변동성을 분석하였다. EOF 분석을 실시한 결과 여름철 대표적인 한반도 강수 패턴은 남한과 북한이 반대의 위상을 가지며 1990년대 중반을 기점으로 레짐 이동이 나타나는 변동 특성을 보였다. 한반도의 여름철 강수는 엘니뇨/라니냐 변동에 따라 적도 동태평양에서 해수면 온도가 증가하는 강한 엘니뇨 해와 적도에서부터 중위도 서태평양까지 남북으로 연결되어 강수량이 증가하는 약한 라니냐 해에 특히 우리나라(남한)의 남부지방에서 증가하는 경향을 보여주었다. 여름철 인도, 북서태평양, 북동아시아 몬순 지수 및 여름철 강수지수에 대한 계절 내 변동에 의해, 우리나라 강수는 6월 인도 몬순 지수와 양의 상관이 있고 7월 북서태평양 몬순 지수와 음의 상관이 있으며 8월 인도 몬순 지수와 가장 높은 음의 상관이 있는 것으로 나타났다.

• 대한지리학회지
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• 제39권6호
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• pp.819-832
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• 2004

본 연구에서는 한국의 14개 지점의 여름철 강수량을 분석하여 1941-1970년과 1971-2000년 기간 사이의 변동을 파악하고. 순별 강수량의 경년 변동과 해양변동 및 전구평균기온 변동과의 관련성을 파악하고자 하였다. 두 기간의 순별 강수량 차이에 의하여 중서부지역, 호남지역, 영동 및 영남지역. 제주도지역으로 구분하였다. 강수량은 8월에 증가하였고 9월에 감소하였다. 중서부지역에서 8월 강수량의 증가 폭이 크며, 이는 호우 빈도의 증가와 관련이 있다. 순별 강우량의 제 2극대기가 9월 초순에서 8월 하순으로 바뀌거나 출현하지 않는다. 점차 8월의 소우기가 사라지면서 장마가 9월 초순까지 이어지는 경향이다. 8월 중순과 9월 중순(혹은 7월 중순)의 강수량 편차는 1971년을 경계로 음에서 양 혹은 양에서 음으로 바뀌는 경향이며. 그 변동은 서서히 진행되고 있다. 대부분 지역에서 강수량 변동은 해양변동 및 전구평균기온과 높은 상관관계가 있다.

• 한국수자원학회논문집
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• 제44권5호
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• pp.339-350
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• 2011

본 연구에서는 Bayesian 통계기법을 이용한 비정상성 빈도해석모형을 토대로 외부 기상인자에 의한 변동성을 고려할 수 있는 계절강수량 예측모형을 구축하였으며, 낙동강유역내의 10개 관측소에서 관측된 37년간의 강수량 자료를 이용하여 연도별 여름강수량을 추출하고 이들 관측소의 여름강수량에 물리적인 영향을 미치는 기상인자로서 SST(sea surface temperature)와 OLR(outgoing longwave radiation)을 공간상관성을 검토하여 선정하였다. 모형의 적합성을 검토하기 위해 2010년 여름강수량 사후 확률분포의 중앙값과 관측치를 비교하였으며, 그 결과 각각 858.2mm와 888.1mm로, 이는 구축된 모형이 적절하게 여름강수량을 모의하고 있음을 보여준다. 2010년 겨울 SST 관측 값과, 예년 평균값으로 가정한 2011년 6월 OLR을 이용하여 2011년 여름강수량을 예측하였다. 예측된 2011년 여름강수량은 967.7mm로, 확률적으로 예년 여름강수량의 평균인 680mm를 상회할 확률이 92.9% 이상인 것으로 나타났으며, 또한 50년 빈도에 해당하는 여름강수량을 추정한 결과, 50년 빈도 여름강수량 1400mm를 상회할 확률도 약 73.7%인 것으로 분석되었다.

• 한국제4기학회:학술대회논문집
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• 한국제4기학회 2004년도 하계학술대회
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• pp.24-25
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• 2004

It is well known that there is an inverse relationship between the strength of Indian summer monsoon Rainfall (ISMR) and extent of Eurasian snow cover/depth in the preceding season. Tibetan snow cover/depth also affects the Asian monsoon rainy season largely. The positive correlation between Tibetan sensible heat flux and southeast Asian rainfall suggest an inverse relationship between Tibetan snow cover and southeast Asian rainfall. Developments in Regional Climate Models suggest that the effect of Tibetan snow on the ISMR can be well studied by Limited Area Models (LAMs). LAMs are used for regional climate studies and operational weather forecast of several hours to 3 days in future. The Eta model developed by the National Center for Environmental Prediction (NCEP), the Fifth-Generation NCAR/Penn State Mesoscale Model (MM5) and Regional Climate Model (RegCM) have been used for weather prediction as well as for the study of present-day climate and variability over different parts of the world. Regional Climate Model (RegCM3) has been widely . used for various mesoscale studies. However, it has not been tested to study the characteristics of circulation features and associated rainfall over India so far. In the present study, Regional Climate Model (RegCM-3) has been integrated from 1 st April to 30th September for the years 1993-1996 and monthly mean monsoon circulation features and rainfall simulated by the model at 55km resolution have been studied for the Indian summer monsoon season. Characteristics of wind at 850hPa and 200hPa, temperature at 500hPa, surface pressure and rainfall simulated by the model have been examined for two convective schemes such as Kuo and Grell with Arakawa-Schubert as the closure scheme, Model simulated monsoon circulation features have been compared with those of NCEP/NCAR reanalyzed fields and the rainfall with those of India Meteorological Department (IMD) observational rainfall datasets, Comparisons of wind and temperature fields show that Grell scheme is closer to the NCEP/NCAR reanalysis, The influence of Tibetan snowdepth in spring season on the summer monsoon circulation features and subsequent rainfall over India have been examined. For such sensitivity experiment, NIMBUS-7 SMMR snowdepth data have been used as a boundary condition in the RegCM3, Model simulation indicates that ISMR is reduced by 30% when 10cm of snow has been introduced over Tibetan region in the month of previous April. The existence of Tibetan snow in RegCM3 also indicates weak lower level monsoon westerlies and upper level easterlies.

• 대한지리학회지
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• 제28권3호
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• pp.193-199
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• 1993

기후를 대기의 종합상태라 볼 때에 어느 지역의 기후요소의 변동 크기는 그 지역의 기후의 특성을 나타내는 하나의 지표가 된다. 특히 우리나라 하계 우기인 6,7,8월 동안의 강우량(1920년~1985년)의 변화경향성, 다우년과 과우년의 발생빈도, 그리고 주기 등에 대해 남한 전역의 표준강우량 및 서울, 대구, 부산, 목포, 강릉, 전주의 6개 지점의 강우를 서로 비교하였다. 그리고 남서기류의 영향이 우리나라의 하계 강우에 어떠한 영향을 미치는지 알아보기 위해 남한의 표준강우량 및 6개 지점의 강우와 인도 하계 몬순(monson) 강우와의 상관관계를 조사하였다. 남한 전역의 표준강우량의 평균은 611.6mm이고 표준편차는 165.5mm로서 평균의 21%이다. 6개 지점별 강수량의 평균은 지역에 따라 차이가 심하고 다우년과 과우년의 발생횟수 역시 지역에 따라 차이가 심하다. 변화경향성을 조사한 통계량 r는 남한 전역의 표준강우량의 경우 0.07이며 각 지점별 강우의 경우에도 비슷한 통계량 크기를 나타냈으며 이러한 값들은 통계적으로 유의하지 않다. 즉, 변화경향성은 없다. 우리나라 하계강우의 주기는 2.4~2.5년, 3.1~3.6년 그리고 7.3년으로 나타났다. 우리나라 하계강우와 인도 하계몬순 강우와의 상관은 대구와 전주같은 내륙지방에서는 크게 나타나고, 그 외 해안에 인접한 지역에서는 잘 나타나지 않고 있다.

• 한국수자원학회:학술대회논문집
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• 한국수자원학회 2016년도 학술발표회
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• pp.519-519
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• 2016

Upper Chenab Canal (UCC) is a non-perennial canal in Punjab Province of Pakistan which provides irrigation water only in summer season. Winter and summer are two distinct cropping season with an average rainfall of about 161 mm and 700 mm respectively. Wheat-rice is common crop rotation being followed in the UCC command area. During winter season, groundwater and rainfall are the main sources of irrigation while canal and ground water is used to fulfil the crop water requirements (CWR) during summer. The objective of current study is to estimate how the irrigation water requirements (IWR) of the two crops are going to change under different conditions of temperature and rainfall. For this purpose, 12 different climatic scenarios were designed by combining the assumptions of three levels of temperature increase under dry, normal and wet conditions of rainfall. Weather records of 13 years (2000-2012) were obtained from PMD (Pakistan Meteorological Department) and CROPWAT model was used to simulate the IWR of the crops under normal and scenarios based climatic conditions. Both crops showed a maximum increase in CWR for temperature rise of $+2^{\circ}C$ i.e. 8.69% and 6% as compared to average. Maximum increment (4.1% and 17.51% respectively) in IWR for both wheat and rice was recorded when temperature rise of $+2^{\circ}C$ is coupled with dry rainfall conditions. March & April during winter and August & September during summer were the months with maximum irrigation requirements. Analysis also showed that no irrigation is needed for rice crop during May and June because of enough rainfall in this area.

• 한국환경과학회지
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• 제4권5호
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• pp.28-28
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• 1995

The aim of the present study is to investigate the interannual variabilities of the East Asia monsoon rainfall associated with the global sea surface temperature anomaly(SSTA). For this study, the summer rainfall(from June to August) over the twenty-eight period of 1961-1988 were analyzed with being divided by nine-subregions over East Asia including Korea, China and Japan. From the analysis of the principal modes explaining the interannual variation, the interannual variabilities of summer rainfalls in South Japan and Korea are larger than those of the other subregions of the East Asia. There is a strong negative correlation between the summer rainfalls of south China and Korea. In this study, the relationship between the summer monsoon of each subregion and SSTs of the tropical NINO regions, of western Pacific warm pool, and of the subtropical ocean were investigated. The longitudinal sections of the lagged cross correlations of the summer rainfal1 anomaly in (a) Korea and (b) south China, and the monthly SSTA in the equatorial(averaged from 65 to 6N) Pacific were analyzed. The negative maximum correlation pattems of Korea''s stammer rainfal1 and SSTs over the eastern Pacific is transfered to positive maximum conrlation over central Pacific region with a biennial periodicity. In South China, the significant positive correlations are found at -12 month lag over the eastern Pacific and maximum negative correlation at 16 month lag over the central Pacific with the quasi-biennial oscillation. But the correlation coefficient reverses completely to that in Korea. In order to investigate the most prevailing interannual variability of rainfall related to the favored SSTA region, the lagged cross correlations between East Asia rainfall and SSTs over the moO regions(NINO 1+2(0-105, 90W-80W), NINO 3(5N-5S, 150W-90W), NINO 4(5N-5S, 160E-l50W) and the western Pacific worm pool (5N-5S, 120E-l60E) were analyzed. Among the lagged cross-correlation cycles in NINO regions, the maximum correlations for the negative lagged months prevail in NINO 1+2 and NINO 3, and the cross correlations for the positive lagged months NINO 4. It is noteworthy that correlation between the western Pacific warm pool SSTA and the monsoon rainfall in Korea and South China have the maximum value at negative 4 month lag. The evolution of the correlation between the East Asia monsoon rainfall and SSTA is linked to the equatorial convective cluster and related to northward propagating situation, and raising the possibility that the East Asia monsoon precipitation may be more fundamentally related to the interaction of intraseasonal oscillations and the sub-regional characteristics including the surface boundary conditions and the behavior of climatological air mass.

• 한국환경과학회지
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• 제4권5호
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• pp.413-426
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• 1995

The aim of the present study is to investigate the interannual variabilities of the East Asia monsoon rainfall associated with the global sea surface temperature anomaly(SSTA). For this study, the summer rainfall(from June to August) over the twenty-eight period of 1961-1988 were analyzed with being divided by nine-subregions over East Asia including Korea, China and Japan. From the analysis of the principal modes explaining the interannual variation, the interannual variabilities of summer rainfalls in South Japan and Korea are larger than those of the other subregions of the East Asia. There is a strong negative correlation between the summer rainfalls of south China and Korea. In this study, the relationship between the summer monsoon of each subregion and SSTs of the tropical NINO regions, of western Pacific warm pool, and of the subtropical ocean were investigated. The longitudinal sections of the lagged cross correlations of the summer rainfal1 anomaly in (a) Korea and (b) south China, and the monthly SSTA in the equatorial(averaged from 65 to 6N) Pacific were analyzed. The negative maximum correlation pattems of Korea's stammer rainfal1 and SSTs over the eastern Pacific is transfered to positive maximum conrlation over central Pacific region with a biennial periodicity. In South China, the significant positive correlations are found at -12 month lag over the eastern Pacific and maximum negative correlation at 16 month lag over the central Pacific with the quasi-biennial oscillation. But the correlation coefficient reverses completely to that in Korea. In order to investigate the most prevailing interannual variability of rainfall related to the favored SSTA region, the lagged cross correlations between East Asia rainfall and SSTs over the moO regions(NINO 1+2(0-105, 90W-80W), NINO 3(5N-5S, 150W-90W), NINO 4(5N-5S, 160E-l50W) and the western Pacific worm pool (5N-5S, 120E-l60E) were analyzed. Among the lagged cross-correlation cycles in NINO regions, the maximum correlations for the negative lagged months prevail in NINO 1+2 and NINO 3, and the cross correlations for the positive lagged months NINO 4. It is noteworthy that correlation between the western Pacific warm pool SSTA and the monsoon rainfall in Korea and South China have the maximum value at negative 4 month lag. The evolution of the correlation between the East Asia monsoon rainfall and SSTA is linked to the equatorial convective cluster and related to northward propagating situation, and raising the possibility that the East Asia monsoon precipitation may be more fundamentally related to the interaction of intraseasonal oscillations and the sub-regional characteristics including the surface boundary conditions and the behavior of climatological air mass.