• Title/Summary/Keyword: Precipitation change

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Change-Point in the Recent (1976-2005) Precipitation over South Korea (우리나라에서 최근 (1976-2005) 강수의 변화 시점)

  • Kim, Chansoo;Suh, Myoung-Seok
    • Atmosphere
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    • v.18 no.2
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    • pp.111-120
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    • 2008
  • This study presents a change-point in the 30 years (1976-2005) time series of the annual and the heavy precipitation characteristics (amount, days and intensity) averaged over South Korea using Bayesian approach. The criterion for the heavy precipitation used in this study is 80 mm/day. Using non-informative priors, the exact Bayes estimators of parameters and unknown change-point are obtained. Also, the posterior probability and 90% highest posterior density credible intervals for the mean differences between before and after the change-point are examined. The results show that a single change-point in the precipitation intensity and the heavy precipitation characteristics has occurred around 1996. As the results, the precipitation intensity and heavy precipitation characteristics have clearly increased after the change-point. However, the annual precipitation amount and days show a statistically insignificant single change-point model. These results are consistent with earlier works based on a simple linear regression model.

Change-point and Change Pattern of Precipitation Characteristics using Bayesian Method over South Korea from 1954 to 2007 (베이지안 방법을 이용한 우리나라 강수특성(1954-2007)의 변화시점 및 변화유형 분석)

  • Kim, Chansoo;Suh, Myoung-Seok
    • Atmosphere
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    • v.19 no.2
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    • pp.199-211
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    • 2009
  • In this paper, we examine the multiple change-point and change pattern in the 54 years (1954-2007) time series of the annual and the heavy precipitation characteristics (amount, days and intensity) averaged over South Korea. A Bayesian approach is used for detecting of mean and/or variance changes in a sequence of independent univariate normal observations. Using non-informative priors for the parameters, the Bayesian model selection is performed by the posterior probability through the intrinsic Bayes factor of Berger and Pericchi (1996). To investigate the significance of the changes in the precipitation characteristics between before and after the change-point, the posterior probability and 90% highest posterior density credible intervals are examined. The results showed that no significant changes have occurred in the annual precipitation characteristics (amount, days and intensity) and the heavy precipitation intensity. On the other hand, a statistically significant single change has occurred around 1996 or 1997 in the heavy precipitation days and amount. The heavy precipitation amount and days have increased after the change-point but no changes in the variances.

A Study on the Change of Precipitation and Temperature with 24 Season by Moving Average Method (이동평균법을 이용한 24절기에 따른 강수량과 기온의 변화에 관한 연구)

  • Park, Ki bum
    • Journal of Environmental Science International
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    • v.27 no.12
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    • pp.1227-1239
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    • 2018
  • In this study, daily precipitation data and daily average temperature data of meteorological observatories in Daegu, Busan, Daejeon, Seoul, Mokpo, and Gwangju cities inland and offshore were analyzed by using moving average method. Were compared. Overall, summarizing changes in precipitation and temperature over the 24 seasons, precipitation and temperature in all six stations increased compared to the past 1960s. In the case of precipitation, precipitation increased at the end of July and early August, whereas precipitation in April, September and early October decreased. In the case of temperature, especially in February, the temperature increased, and in Mokpo, the temperature from August to December showed a general decline. Changes in precipitation and temperature due to seasons in the 24 seasons affect agriculture and our everyday life, and further research is needed to determine how these changes will affect agricultural water supply, crop growth and daily life. The results of this study can be useful.

Regional Division of Korea by Precipitation Days and Annual Change Pattern (강수일과 그 연변화형에 의한 한국의 지역구분)

  • Park, Hyun-Wook
    • Journal of Environmental Science International
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    • v.4 no.5
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    • pp.1-1
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    • 1995
  • An attempt was made to study the subdivision of Korea by the annual amount and the annual change pattern of monthly precipitation days(that is one of the important elements of the precipitation characteristics), using the mean values for the years 1961-1990 at the 68 stations. The amplitudes of annual change were normalized and using these values, the principal component analysis was applied to determine the annual change patterns. The results show that they are expressed by the combinations of the three change patterns in almost whole regions of Korea. As a result,the annual change pattern of precipitation days in Korea is classified into 8 types from A to e,in detail, 36 types from A0 to e$\circled2$.And regional division of precipitation days in Korea is divided into 13 regions from I a to IIIC,into detail, 41 regions from I no to IIICl.

Regional Division of Korea by Precipitation Days and Annual Change Pattern (강수일과 그 연변화형에 의한 한국의 지역구분)

  • 박현욱
    • Journal of Environmental Science International
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    • v.4 no.5
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    • pp.387-402
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    • 1995
  • An attempt was made to study the subdivision of Korea by the annual amount and the annual change pattern of monthly precipitation days(that is one of the important elements of the precipitation characteristics), using the mean values for the years 1961-1990 at the 68 stations. The amplitudes of annual change were normalized and using these values, the principal component analysis was applied to determine the annual change patterns. The results show that they are expressed by the combinations of the three change patterns in almost whole regions of Korea. As a result, the annual change pattern of precipitation days in Korea is classified into 8 types from A to e, in detail, 36 types from A0 to e$\circled2$.And regional division of precipitation days in Korea is divided into 13 regions from I a to IIIC, into detail, 41 regions from I no to IIICl.

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SIMULATION OF SOIL MOISTURE VARIABILITY DUE TO CLIMATE ORANGE IN NORTHEAST POND RIVER WATERSHED, NEWFOUNDLAND, CANADA

  • A. Ghosh Bobba;Vijay P. Singh
    • Water Engineering Research
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    • v.4 no.1
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    • pp.31-43
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    • 2003
  • The impacts of climate change on soil moisture in sub - Arctic watershed simulated by using the hydrologic model. A range of arbitrary changes in temperature and precipitation are applied to the runoff model to study the sensitivity of soil moisture due to potential changes in precipitation and temperature. The sensitivity analysis indicates that changes in precipitation are always amplified in soil moisture with the amplification factor for flow. The change in precipitation has effect on the soil moisture in the catchment. The percentage change in soil moisture levels can be greater than the percentage change in precipitation. Compared to precipitation, temperature increases or decreases alone have impacts on the soil moisture. These results show the potential for climate change to bring about soil moisture that may require a significant planning response. They are also indicative of the fact that hydrological impacts affecting water supply may be important in consider-ing the cost and benefits of potential climate change.

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The Statistical Approaches on the Change Point Problem Precipitation in the Pusan Area (부산지방 강수량의 변화시점에 관한 통계적 접근)

  • 박종길;석경하
    • Journal of Environmental Science International
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    • v.7 no.1
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    • pp.1-7
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    • 1998
  • This paper alms to estimate the change point of the precipitation in Pusan area using the several statistical approaches. The data concerning rainfall are extracted from the annual climatological report and monthly weather report issued by the Korean Meteorological Administration. The average annual precipitation at Pusan is 1471.6 mm, with a standard deviation of 406.0 mm, less than the normal(1486.0 mm). The trend of the annual precipitation is continuously decreasing after 1991 as a change point. And the statistical tests such as t-test and Wilcoxon rank sum test reveals that the average annual precipitation of after 1991 is less than that of before 1991 at 10% significance level. And the mean gnu성 precipitation In Kyongnam districts is also continuously decreasing after 1991 same as Pusan.

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Investigating Changes over Time of Precipitation Indicators (강수지표의 시간에 따른 변화 조사)

  • Han, Bong-Koo;Chung, Eun-Sung;Lee, Bo-Ram;Sung, Jang Hyun
    • Journal of Wetlands Research
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    • v.15 no.2
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    • pp.233-250
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    • 2013
  • Gradually or radically change how the characteristics of the climate characteristic using change point analysis for the precipitation indicators were investigated. Significantly the amount, extreme and frequency were separated by precipitation indicators, each indicator RIA(Rainfall Index for Amount), RIE(Rainfall Index for Extremes) and RIF(Rainfall Index for Frequency) was defined. Bayesian Change Point was applied to investigate changing over time of precipitation indicators calculated. As the result of analysis, precipitation indicators in South Korea was found to recently increase all indicators except for the annual precipitation days and 200-yr precipitation. RIA revealed that there was a very clear point of significance for the change in Ulleungdo, Relatively significant results for RIE were identified in Gumi, Jecheon and Seogwipo. Also, since the 1990s, an increase in the number of variation points, and the horizontal width of the fluctuation point was being relatively wider. Based on these results, rethink the precipitation on the assumption of stationarity was judged necessary.

On the Characteristics of the Precipitation Patterns in Korea Due to Climate Change

  • Park, Jong-Kil;Seong, Ihn-Cheol;Kim, Baek-Jo;Jung, Woo-Sik;Lu, Riyu
    • Journal of Environmental Science International
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    • v.23 no.1
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    • pp.25-37
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    • 2014
  • In the present study, we analyzed precipitation patterns and diurnal variation trends of hourly precipitation intensity due to climate change. To that end, we used the hourly precipitation data obtained from 26 weather stations around South Korea, especially Busan, from 1970 to 2009. The results showed that the hourly precipitation was concentrated on a specific time of day. In particular, the results showed the so-called "morning shift" phenomenon, which is an increase in the frequency and intensity of hourly precipitation during the morning. The morning shift phenomenon was even more pronounced when a higher level of hourly precipitation intensity occurred throughout the day. Furthermore, in many regions of Korea, including Busan, this morning shift phenomenon became more prevalent as climate change progressed.

Interdecadal Variability and Future Change in Spring Precipitation over South Korea (한반도 봄철 강수량의 장기변동과 미래변화)

  • Kim, Go-Un;Ok, Jung;Seo, Kyong-Hwan;Han, Sang-Dae
    • Atmosphere
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    • v.22 no.4
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    • pp.449-454
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    • 2012
  • This study presents the long-term variability of spring precipitation over the Korean peninsula. It is found that the significant interdecadal change in the spring precipitation has occurred around year 1991. Over the Korean peninsula the precipitation for the post-1991 period increased by about 30 mm per year in CMAP and station-measured data compared to the precipitation prior to year 1991. Due to an increased baroclinicity during the later period, the low-level negative pressure anomaly has developed with its center over northern Japan. Korea is situated at the western end of the negative pressure anomaly, receiving moisture from westerly winds and producing more precipitation. Also, we estimate the change in the near future (years 2020~2040) spring precipitation using six best performing Coupled Model Intercomparison Project 3 (CMIP3) models. These best model ensemble mean shows that spring precipitation is anticipated to increase by about 4% due to the strengthened westerlies accompanied by the northwestern enhancement of the North Pacific subtropical high.