• Title/Summary/Keyword: EL Nino

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Analysis of Stationary Time Series Using Wavelet Transform (Wavelet 변환을 이용한 정상 시계열 데이터 해석에 관한 연구)

  • Lee, Joon-Tark;Choi, Woo-Jin;Kim, Tae-Hong
    • Proceedings of the KIEE Conference
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    • 1999.07b
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    • pp.969-971
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    • 1999
  • Wavelet analysis is applying to many fields such as the time-frequency localization of a time series and a time varying data. In this paper, a statistical testing based Wavelet power spectrum analysis for the stationary Nino3 Sea Surface Temperature(SST) data was executed. Specially, the 95% confidence level for SST was effective in searching the periods of El-Nino using various wavelet basis functions.

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Impact of ENSO on Time-Spatial Characteristics of Probable Rainfall Frequency Analysis (ENSO가 한반도의 확률강우량의 시공간 특성에 미치는 영향)

  • Kim, Byung-Sik;Kim, Soo-Jun;Kim, Hung-Soo
    • Proceedings of the Korea Water Resources Association Conference
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    • 2008.05a
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    • pp.309-313
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    • 2008
  • 본 논문의 목적은 ENSO의 영향에 의한 우리나라 강우의 특성을 분석하는 것이다. 따라서 우리나라 기상관측소의 강우량 자료를 Warm(El Nino), Cold(La Nina), Normal 에피소드에 따라 기간별로 분류하였다. 또한 이렇게 분류한 자료는 Markov Chain 모형을 이용하여 100년의 자료로 모의 발생하였고 에피소드별로 빈도분석을 실시하였다. 빈도분석 결과 에피소드에 따라 각 기상관측소별로 강우의 크기에 영향을 미치고 있음을 알 수 있었다. 또한 군집분석을 실시하여 각 에피소드의 공간적인 영향에 대해서 분석하였다. 결과적으로 Warm(El Nino), Cold(La Nina) and Normal 에피소드로 대표되는 ENSO는 우리나라의 강우특성에 크게 영향을 미치는 것으로 파악되었다.

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Comparison of variations in sea surface height with sea surface temperature and wind field in the Tropical Pacific Ocean

  • Chul, Kang-Sung;Schumann, Robert;Murai, Shunji;Kiyoshi, Honda;Kim, Young-Seup
    • Proceedings of the KSRS Conference
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    • 1998.09a
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    • pp.225-230
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    • 1998
  • The purpose of this study is to contribute the development of an El Nino prediction model. The objectives of the study are to (1) extract sea surface height data from the TOPEI/Poseidon altimeter, and (2) compare the relations among the sea surface height, sea surface temperature and wind field. NOAA AVHRR Multi-channel data is used for sea surface temperature and wind data is derived from ERS 1, 2 AMI wind scatterometer. The results showed that sea surface height has increased significantly during the El Nino season. The sea surface height is positively related to sea surface temperature and negatively related to zonal wind.

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Statistical Characteristics of Southern Oscillation and its Barometric Pressure Data

  • Kawamura, Akira;Jinno, Kenji;Eguchi, Soichiro
    • Proceedings of the Korea Water Resources Association Conference
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    • 2002.05b
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    • pp.1195-1204
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    • 2002
  • The impacts of El Nino Southern Oscillation (ENSO) phenomenon on climate are widespread and extend far beyond the tropical Pacific. The phenomenon can be characterized by Southern Oscillation Index (SOI) which is derived from values of the monthly mean sea level pressure barometric difference between Tahiti and Darwin, Australia. Its best-known extreme is the El Nino event. In this study, general statistical characteristics of SOI and the data from which it is derived (i.e. mean sea level pressure data at Tahiti and Darwin) are presented as guidance when using SOI far other analyses. The characteristics include the availability of the barometric pressure data, statistics of monthly pressure data, correlation of SO intensity, frequency analysis of SOI by magnitude and by month (January-December), duration properties of SOI by run analysis.

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Annual Cycle and Interannual Variability of Tropical Cyclone Genesis Frequency in the CMIP5 Climate Models: Use of Genesis Potential Index (CMIP5 기후모델에서 나타나는 열대저기압 생성빈도의 연진동과 경년변동성: 잠재생성지수의 이용)

  • Kwon, MinHo
    • Journal of the Korean earth science society
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    • v.33 no.7
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    • pp.583-595
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    • 2012
  • The potential for tropical cyclogenesis in a given oceanic and atmospheric environments can be represented by genesis potential index (GPI). Using the 18 Coupled Model Inter Comparison Project phase 5 (CMIP5) models, the annual cycle of GPI and interannual variability of GPI are analyzed in this study. In comparison, the annual cycle of GPI calculated from reanalysis data is revisited. In particular, GPI differences between CMIP5 models and reanalysis data are compared, and the possible reasons for the GPI differences are discussed. ENSO (El Nino and Southern Oscillation) has a tropical phenomenon, which affects tropical cyclone genesis and its passages. Some dynamical interpretations of tropical cyclogenesis are suggested by using the fact that GPI is a function of four large-scale parameters. The GPI anomalies in El Nino or La Nina years are discussed and the most contributable factors are identified in this study. In addition, possible dynamics of tropical cyclogenesis in the Northern Hemisphere Pacific region are discussed using the large-scale factors.

Assessment of Teleconnection based Long-Range Flood Risk Prediction during different El Ni?o phases: A Case Study of Gyeongnam (원격상관기반 엘니뇨 시기별 홍수위험 장기예측 평가: 경남지자체 대상)

  • Yoon, Sun-Kwon
    • Proceedings of the Korea Water Resources Association Conference
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    • 2016.05a
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    • pp.91-91
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    • 2016
  • 본 연구는 대규모 대기환경패턴 변화에 따른 극한 기후발생 및 극치 수문사상의 지역적 변동 특성을 분석하였고, 통계기법을 이용한 기후지수와 수문변량간의 원격상관관계 분석결과를 이용하여 한반도 중 장기 수문변량 예측의 가능성을 진단하였다. 또한 경남 지자체를 대상으로 다양한 통계예측모형(AR, MA, ARMA, ARIMA, VAR)을 구축하여 그 예측능력을 평가하고 적용성을 검토하였고, 중 장기 통합홍수위험 평가를 위한 인덱스를 개발하였다. 서로 다른 엘니뇨 시기별 홍수 위험도 평가결과 전형적인 엘니뇨(Cold Tongue El Nino)해에는 남해안 일부 지역(거제시, 남해군)에서 위험도가 높게 산정되었으며, 경남 북부지역에서는 위험도가 매우 낮게 산정되었다. 중앙태평양 엘니뇨(Warm Pool El Nino) 해에는 경남 남부 지역을 중심으로 홍수위험지수가 높게 나타나 중앙태평양 엘니뇨가 발달 시 경남지역의 홍수위험 발생 가능성 평년에 비하여 큰 것으로 분석된다. 또한 라니냐(La Nina) 해에는 경남 서쪽일부 지역(남해군, 하동군, 산청군)에서 통합홍수위험지수가 높게 나타났으며, 나머지 지역에서는 홍수위험도가 작거나 중간 값을 보이는 것으로 분석되었다. 본 연구는 중 장기적 관점에서 수자원 예측 및 효율적인 물 관리와 안정적인 용수공급에 도움을 줄 것으로 사료되며, 한반도 대상 특정 엘니뇨 해의 지자체별 홍수위험 취약성 평가에 활용이 가능할 것이다.

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El Niño-Southern Oscillation, Indian Ocean Dipole Mode, a Relationship between the Two Phenomena, and Their Impact on the Climate over the Korean Peninsula (엘니뇨-남방진동, 인도양 쌍극자 모드, 두 현상의 관련성, 그리고 한반도 기후에 대한 영향)

  • Cha, Eun-Jeong
    • 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.

Seasonal Relationship between El Nino-Southern Oscillation and Hydrologic Variables in Korea (ENSO와 한국의 수문변량들간의 계절적 관계 분석)

  • Chu, Hyun-Jae;Kim, Tae-Woong;Lee, Jong-Kyu;Lee, Jae-Hong
    • Journal of Korea Water Resources Association
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    • v.40 no.4
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    • pp.299-311
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    • 2007
  • Climatic abnormal phenomena involving El Nino and La Nina have been frequently reported in recent decades. The interannual climate variability represented by El Nino-Southern Oscillation (ENSO) is sometimes investigated to account for the climatic abnormal phenomena around the world. Although many hydroclimatologists have studied the impact of ENSO on regional precipitation and streamflow, however, there are still many difficulties in finding the dominant causal relationship between them. This relationship is very useful in making hydrological forecasting models for water resources management. In this study, the seasonal relationships between ENSO and hydrologic variables were investigated in Korea. As an ENSO indicator, Southern Oscillation Index (SOI) was used. Monthly precipitation, monthly mean temperature, and monthly dam inflow data were used after being transformed to the standardized normal index. Seasonal relationships between ENSO and hydrologic variables were investigated based on the exceedance probability and distribution of hydrologic variables conditioned on the ENSO episode. The results from the analysis of this study showed that the warm ENSO episode affects increases in precipitation and temperature, and the cold ENSO episode is related with decreases in precipitation and temperature in Korea. However, in some regions, the local relationships do not correspond with the general seasonal relationship.