Holocene coastal environmental change and ENSO-driven hydroclimatic variability in East Asia. (15th September 2019)

• Record Type: Journal Article
• Authors: Lim, Jaesoo; Lee, Jin-Young; Hong, Sei-Sun; Park, Sujeong; Lee, Eunmi; Yi, Sangheon
• Is Part Of: Quaternary science reviews. Volume 220(2019)
• Page Start: 75
• Page End: 86
• Publication Date: 2019-09-15
• Subjects: El Niño Southern Oscillation (ENSO) -- Flooding -- Holocene -- Tropical typhoon -- Carbon isotope (δ13C) -- Sulfur isotope (δ34S); Geology, Stratigraphic -- Quaternary -- Periodicals; Stratigraphie -- Quaternaire -- Périodiques; 551.79
• DOI: 10.1016/j.quascirev.2019.07.041
• Languages: English
• ISSNs: 0277-3791

Abstract

Abstract: Understanding the past natural behavior of coastal hydroclimates at multi-centennial time scales is essential for planning coastal strategies in preparation for anticipated climate change. We investigated the elemental and isotopic features of 10-m-long coastal sedimentary cores from Goheung Bay located on the southern coast of Korea to extract such natural variability. Based on the relationships among total organic carbon (TOC), total sulfur (TS) content, and their isotopic values (δ 13 CTOC and δ 34 STS ), we reconstructed the long-term coastal evolution in the area and compared this with the reported Holocene sea level change. Time series data of the titanium (Ti)/aluminum (Al) ratio, as a proxy for riverine terrigenous input, revealed a strong link to terrestrial plant contribution, as indicated by δ 13 CTOC variability, suggesting past hydroclimatic change in the study area. The short-term variability of Ti/Al ratios correlated well with flooding events reconstructed for the Nakdong River in Korea. Moreover, periods in which the Ti/Al ratio was higher corresponded to those of stronger El Niño Southern Oscillation (ENSO) activity, suggesting ENSO-driven hydroclimatic changes in southern Korea. Especially, the periods of higher Ti/Al ratios during the late Holocene corresponded to a higher frequency of typhoon-driven overwash events along the southwestern coast of Japan. These similarities suggest that past freshwater input events along the southern coast of Korea were influenced considerably by typhoon-driven heavy rains during stronger ENSO activity. Spectral analysis of the Ti/Al ratios revealed significant periodicities of 1550, 780, 140, 120 and 105 years, suggesting centennial to millennial-timescale variability in hydroclimatic change and typhoon activity over East Asia. Highlights: δ 13 CTOC and δ 34 STS were tested to reconstruct the Holocene coastal evolution. Periods of higher Ti/Al ratios corresponded to those of stronger ENSO activity. Ti/Al ratios revealed significant periodicities of 1550, 780, 140, 120 and 105 years. Multi-centennial variability in hydroclimate and typhoon activity was tested.