scholarly journals A Spatiotemporal Analysis of Historical Droughts in Korea

2011 ◽  
Vol 50 (9) ◽  
pp. 1895-1912 ◽  
Author(s):  
Do-Woo Kim ◽  
Hi-Ryong Byun ◽  
Ki-Seon Choi ◽  
Su-Bin Oh
Keyword(s):  
South Korea ◽  
Return Period ◽  
Summer Rainfall ◽  
Hierarchical Cluster ◽  
Spatiotemporal Analysis ◽  
Dry Season ◽  
Coastal Regions ◽  
Drought Intensity ◽  
Daily Precipitation Data

AbstractThe climatological characteristics of drought in South Korea were investigated using daily precipitation data for 1777–2008. The effective drought index was used to quantify the drought intensity. As a result, five characteristics were discovered. First, South Korea can be divided into four drought subregions (the central, southern, and east coastal regions and Jeju Island) using hierarchical cluster analysis. Second, a map for long-term drought conditions in the four subregions is created that allows identification of the spatiotemporal distribution of droughts for the 231 yr at a glance. Third, droughts in South Korea have time scales that depend on the onset season. Spring (March–May) droughts tend to be short (≤200 days) because the summer (June–September) rainy season follows. Summer droughts tend to be long (>200 days) because the dry season (October–February) follows. In the dry season, droughts tend to be sustained or become severe rather than being initiated or relieved. Fourth, 5-, 14-, 34-, and 115-yr drought cycles were identified by spectral analysis. The 5-yr cycle was dominant in all of the regions, the 14-yr cycle was observed over the southern and east coastal regions, and the 34-yr cycle was observed over the central region. Fifth, the most extreme drought occurred in 1897–1903 (return period: 233 yr) and was associated with the 115-yr drought cycle. After this drought, severe droughts (return period of >10 yr) occurred in 1927–30, 1938–40, 1942–45, 1951–52, 1967–69, and 1994–96; they were caused by the consecutive shortage of summer rainfall for two or more years.

scholarly journals The Spatiotemporal Distribution of Flash Floods and Analysis of Partition Driving Forces in Yunnan Province

2019 ◽  
Vol 11 (10) ◽  
pp. 2926 ◽  
Author(s):  
Junnan Xiong ◽  
Chongchong Ye ◽  
Weiming Cheng ◽  
Liang Guo ◽  
Chenghu Zhou ◽  
...  
Keyword(s):  
Sensitivity Analysis ◽  
Economic Development ◽  
Return Period ◽  
Driving Forces ◽  
Flash Flood ◽  
Temporal Distribution ◽  
Heavy Precipitation ◽  
Spatiotemporal Analysis ◽  
Flash Floods

Flash floods are one of the most serious natural disasters, and have a significant impact on economic development. In this study, we employed the spatiotemporal analysis method to measure the spatial–temporal distribution of flash floods and examined the relationship between flash floods and driving factors in different subregions of landcover. Furthermore, we analyzed the response of flash floods on the economic development by sensitivity analysis. The results indicated that the number of flash floods occurring annually increased gradually from 1949 to 2015, and regions with a high quantity of flash floods were concentrated in Zhaotong, Qujing, Kunming, Yuxi, Chuxiong, Dali, and Baoshan. Specifically, precipitation and elevation had a more significant effect on flash floods in the settlement than in other subregions, with a high r (Pearson’s correlation coefficient) value of 0.675, 0.674, 0.593, 0.519, and 0.395 for the 10 min precipitation in 20-year return period, elevation, 60 min precipitation in 20-year return period, 24 h precipitation in 20-year return period, and 6 h precipitation in 20-year return period, respectively. The sensitivity analysis showed that the Kunming had the highest sensitivity (S = 21.86) during 2000–2005. Based on the research results, we should focus on heavy precipitation events for flash flood prevention and forecasting in the short term; but human activities and ecosystem vulnerability should be controlled over the long term.

Long-term change of warm-season precipitation climatology in South Korea

2020 ◽  
Author(s):  
Hyeon-seok Do ◽  
Joowan Kim
Keyword(s):  
South Korea ◽  
Daily Precipitation ◽  
Warm Season ◽  
Precipitation Intensity ◽  
Precipitation Data ◽  
Precipitation Characteristics ◽  
Daily Precipitation Data ◽  
Long Term Changes ◽  
Precipitation Increase

<div> <div> <div> <p>This study examines long-term changes of precipitation characteristics in South Korea focusing on warm season (June-September). Daily precipitation data are obtained from 15 surface stations that have continuously observed precipitation for 58 years (1961 – 2018). Precipitation characteristics and their long-term changes are examined including trend, amount, and intensity. The warm- season precipitation in South Korea is largely affected by the East Asian Summer Monsoon, which causes rainy season in late July and mid August (these are called “Changma” and “Post-Changma” seasons in Korea). Thus, these characteristics are also analyzed focusing on Changma season.</p> <p>The warm-season precipitation increased roughly by 1.0 mm per day for the last thirty years. The change is particularly pronounced during Changma season, and it shows 1.6 mm of daily precipitation increase. Trend analysis for the 58 years also showed a consistent and significant result. The precipitation change is mostly founded in the intensity of 30 – 110 mm per day implying that the precipitation intensity is increasing in warm season. Multiple regression analysis further suggests that this change is more related to precipitation intensity than precipitation frequency. Global precipitation data reveals the similar change in precipitation over central eastern China presenting a band-like precipitation increase extending to the Korean peninsula. These results are likely caused by near-surface temperature and moisture increase in a warming climate.</p> </div> </div> </div>

scholarly journals Regional variability in black carbon and carbon monoxide ratio from long-term observations over East Asia: assessment of representativeness for black carbon (BC) and carbon monoxide (CO) emission inventories

2020 ◽  
Vol 20 (1) ◽  
pp. 83-98 ◽  
Author(s):  
Yongjoo Choi ◽  
Yugo Kanaya ◽  
Seung-Myung Park ◽  
Atsushi Matsuki ◽  
Yasuhiro Sadanaga ◽  
...  
Keyword(s):  
Carbon Monoxide ◽  
South Korea ◽  
East Asia ◽  
Black Carbon ◽  
North Korea ◽  
Northeast China ◽  
Emission Inventory ◽  
East China ◽  
Co Emission

Abstract. The black carbon (BC) and carbon monoxide (CO) emission ratios were estimated and compiled from long-term, harmonized observations of the ΔBC∕ΔCO ratios under conditions unaffected by wet deposition at four sites in East Asia, including two sites in South Korea (Baengnyeong and Gosan) and two sites in Japan (Noto and Fukuoka). Extended spatio-temporal coverage enabled estimation of the full seasonality and elucidation of the emission ratio in North Korea for the first time. The estimated ratios were used to validate the Regional Emission inventory in ASia (REAS) version 2.1 based on six study domains (“East China”, “North China”, “Northeast China”, South Korea, North Korea, and Japan). We found that the ΔBC∕ΔCO ratios from four sites converged into a narrow range (6.2–7.9 ng m−3 ppb−1), suggesting consistency in the results from independent observations and similarity in source profiles over the regions. The BC∕CO ratios from the REAS emission inventory (7.7 ng m−3 ppb−1 for East China – 23.2 ng m−3 ppb−1 for South Korea) were overestimated by factors of 1.1 for East China to 3.0 for South Korea, whereas the ratio for North Korea (3.7 ng m−3 ppb−1 from REAS) was underestimated by a factor of 2.0, most likely due to inaccurate emissions from the road transportation sector. Seasonal variation in the BC∕CO ratio from REAS was found to be the highest in winter (China and North Korea) or summer (South Korea and Japan), whereas the measured ΔBC∕ΔCO ratio was the highest in spring in all source regions, indicating the need for further characterization of the seasonality when creating a bottom-up emission inventory. At levels of administrative districts, overestimation in Seoul, the southwestern regions of South Korea, and Northeast China was noticeable, and underestimation was mainly observed in the western regions in North Korea, including Pyongyang. These diagnoses are useful for identifying regions where revisions in the inventory are necessary, providing guidance for the refinement of BC and CO emission rate estimates over East Asia.

scholarly journals Is Establishing a New Partnership Useful Information for Investors in the Smartphone Supply Market?

2021 ◽  
Vol 13 (10) ◽  
pp. 5573
Author(s):  
Insung Son ◽  
Sihyun Kim
Keyword(s):  
South Korea ◽  
Stock Price ◽  
Individual Investors ◽  
Trading Patterns ◽  
Market Impacts ◽  
The Us ◽  
Signaling Effect ◽  
Parts Suppliers ◽  
Country Specific

This study analyzed partner volatility (new, old, revocation partners) and country-specific signal effects (United States (US), Taiwan, Japan, and South Korea) for Apple iPhone parts suppliers from 2007 to 2018. Mid- to long-term stock price movements were also analyzed to define trading patterns by investor type. The results using logit regression analysis revealed that new partners and revocation partners each have a signaling effect perceived as positive and negative information in the short term, and the excess returns by country showed a positive signaling effect in the order of the US, Taiwan, South Korea, and Japan. The findings also suggest that the change in the new partners’ stock price after the preannouncement of new products was useful investment information. Moreover, information asymmetry was found between individual investors, institutions, and foreigners. Results indicate that new partner selection in the smartphone market impacts corporate value and serves as useful investment information.

From gradual erosion to revitalization: National Social Dialogue Institutions and policy effectiveness

2021 ◽  
pp. 095968012110183
Author(s):  
Igor Guardiancich ◽  
Oscar Molina
Keyword(s):  
Decision Making ◽  
Problem Solving ◽  
South Korea ◽  
Industrial Relations ◽  
Political Support ◽  
Policy Effectiveness ◽  
Substantial Evidence ◽  
Social Dialogue ◽  
Socioeconomic Issues

We explore the factors behind the long-term erosion of National Social Dialogue Institutions (NSDIs) to provide insights about the conditions for their revitalization. By applying policy analysis insights into the industrial relations field, we argue that limited policy effectiveness goes a long way towards explaining the erosion experienced by many NSDIs worldwide in recent years. Drawing on a global survey and on case studies of NSDIs in Brazil, Italy and South Korea, we show that these institutions’ policy effectiveness crucially depends on combinations of their problem-solving capacity, an encompassing mandate to deal with relevant socioeconomic issues and an enabling environment that grants the inclusion of social dialogue into decision making. With regard to rekindling their role, the article provides substantial evidence that two sub-dimensions of effectiveness are key: enjoying political support and having an ‘effective mandate’ as opposed to relying on just a formal remit to deal with socioeconomic issues of interest.

Rising ecosystem water demand exacerbates the lengthening of tropical dry seasons

2021 ◽  
Author(s):  
Hao Xu ◽  
Xu Lian ◽  
Ingrid Slette ◽  
Hui Yang ◽  
Yuan Zhang ◽  
...  
Keyword(s):  
Water Demand ◽  
Potential Evapotranspiration ◽  
Central Africa ◽  
Dry Season ◽  
Land Area ◽  
Key Factor ◽  
Dry Seasons ◽  
The Tropics ◽  
Factor Governing

Abstract The timing and length of the dry season is a key factor governing ecosystem productivity and the carbon cycle of the tropics. Mounting evidence has suggested a lengthening of the dry season with ongoing climate change. However, this conclusion is largely based on changes in precipitation (P) compared to its long-term average (P ̅) and lacks consideration of the simultaneous changes in ecosystem water demand (measured by potential evapotranspiration, Ep, or actual evapotranspiration, E). Using several long-term (1979-2018) observational datasets, we compared changes in tropical dry season length (DSL) and timing (dry season arrival, DSA, and dry season end, DSE) among three common metrics used to define the dry season: P < P ̅, P < Ep, and P < E. We found that all three definitions show that dry seasons have lengthened in much of the tropics since 1979. Among the three definitions, P < E estimates the largest fraction (49.0%) of tropical land area likely experiencing longer dry seasons, followed by P < Ep (41.4%) and P < P ̅ (34.4%). The largest differences in multi-year mean DSL (> 120 days) among the three definitions occurred in the most arid and the most humid regions of the tropics. All definitions and datasets consistently showed longer dry seasons in southern Amazon (due to delayed DSE) and central Africa (due to both earlier DSA and delayed DSE). However, definitions that account for changing water demand estimated longer DSL extension over those two regions. These results indicate that warming-enhanced evapotranspiration exacerbates dry season lengthening and ecosystem water deficit. Thus, it is necessity to account for the evolving water demand of tropical ecosystems when characterizing changes in seasonal dry periods and ecosystem water deficits in an increasingly warmer and drier climate.

scholarly journals Long-term change in April mean Precipitation in Gwangju, South Korea

2014 ◽  
Vol 9 (3) ◽  
pp. 181-192
Author(s):  
Ki-Seon Choi ◽  
◽  
Baek-Jo Kim ◽  
Jeoung-Yun Kim ◽  
Ki-Jun Park ◽  
...  
Keyword(s):  
South Korea ◽  
Term Change
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