https://repository.kopri.re.kr/handle/201206/14798 Wed, 08 Apr 2026 23:45:03 GMT 2026-04-08T23:45:03Z https://repository.kopri.re.kr/handle/201206/15322 Title: Isotopic evolution of snowmelt and its hydrometeorological importance in snow-covered regions Authors: Nyamgerel Yalalt; Han, Yeongcheol; Lee Jeonghoon Abstract: Snowmelt, a component of the hydrological cycle, is influenced by changing climate and meteorological events. In the context of hydrometeorological studies, the water isotopic composition of snowmelt has been commonly used. This study examined temporal variations in the isotopic composition of snowmelt from an isotopically heterogeneous snowpack to the context of accurate quantification of isotope-based hydrograph separation. In this study, a one-dimensional model was used to simulate the isotopic variations of the meltwater by varying the initial isotopic compositions of the snow layers and parameters such as effectiveness of exchange (psi), ice-to-liquid ratio of the exchange system (f), and water saturation (S). Isotopic evolution is sensitive to the initial layer sequence of isotopically enriched or depleted snow in the snowpack and the extent of isotopic differences between the layers. More variated patterns are observed in the isotopic evolution as the psi and f values are increased; particularly, a significant modification is observed in the bottom layer that is altered by the enriched top layer, thereby further affecting the pattern of isotopic evolution. The isotopic heterogeneity has been suggested to be a significant factor in the isotopic evolution of snowmelt, even though various other influencing factors have been considered under natural conditions. Because of the close dependence of snow and glacial conditions upon climate change, this study is expected to support further hydrometeorological studies, particularly in snow-dominated regions. Mon, 01 Jan 2024 00:00:00 GMT https://repository.kopri.re.kr/handle/201206/15322 2024-01-01T00:00:00Z https://repository.kopri.re.kr/handle/201206/16188 Title: Millennial-scale variability of Greenland dust provenance during the last glacial maximum as determined by single particle analysis Authors: Ro, Seokhyun; Park Jonghyeon; Yoo Hanjin; Han Changhee; Lee, Ahhyung; Lee Yoojin; Kim, Minjeong; Han, Yeongcheol; Svensson Anders; Shin, Jinhwa; Ro Chul-Un; Hong Sungmin Abstract: Greenland ice core records exhibited 100-fold higher dust concentrations during the Last Glacial Maximum (LGM) than during the Holocene, and dust input temporal variability corresponded to different climate states in the LGM. While East Asian deserts, the Sahara, and European loess have been suggested as the potential source areas (PSAs) for Greenland LGM dust, millennial-scale variability in their relative contributions within the LGM remains poorly constrained. Here, we present the morphological, mineralogical, and geochemical characteristics of insoluble microparticles to constrain the provenance of dust in Greenland NEEM ice core samples covering cold Greenland Stadials (GS)-2.1a to GS-3 (similar to 14.7 to 27.1 kyr ago) in the LGM. The analysis was conducted on individual particles in microdroplet samples by scanning electron microscopy with energy dispersive X-ray spectroscopy and Raman microspectroscopy. We found that the kaolinite-to-chlorite (K/C) ratios and chemical index of alteration (CIA) values were substantially higher (K/C: 1.4 +/- 0.7, CIA: 74.7 +/- 2.9) during GS-2.1a to 2.1c than during GS-3 (K/C: 0.5 +/- 0.1, CIA: 65.8 +/- 2.8). Our records revealed a significant increase in Saharan dust contributions from GS-2.1a to GS-2.1c and that the Gobi Desert and/or European loess were potential source(s) during GS-3. This conclusion is further supported by distinctly different carbon contents in particles corresponding to GS-2.1 and GS-3. These results are consistent with previous estimates of proportional dust source contributions obtained using a mixing model based on Pb and Sr isotopic compositions in NEEM LGM ice and indicate millennial-scale changes in Greenland dust provenance that are probably linked to large-scale atmospheric circulation variabilities during the LGM. Mon, 01 Jan 2024 00:00:00 GMT https://repository.kopri.re.kr/handle/201206/16188 2024-01-01T00:00:00Z https://repository.kopri.re.kr/handle/201206/14966 Title: High snow accumulation observed on Amundsen Sea coastal ice rise, West Antarctica Authors: Hong, Sang-Bum; Yalalt Nyamgerel; Lee, Won Sang; Jeonghoon Lee Abstract: Polar snow and its accumulation preserve valuable information derived from the atmosphere on past climate and environmental changes in high resolution, particularly in coastal sites. A 2.5-m snow-pit was excavated from the coastal ice rise (Moore Dome) near Amundsen Sea region in February 2012. This study evaluated the isotopic and chemical compositions in the snow-pit and compared them with meteorological variables. Based on the seasonal peaks of the MSA and nssSO42- together with δ18O, δD, and d-excess, the snow-pit record was corresponded to accumulation during austral winter 2011 to summer 2011/2012. The annual mean accumulation rate was assumed thus to be as large as or even higher than 1.03 m w.e. yr-1 at this site. A relatively warm winter temperature in 2011 was traceable in the variations of δ18O, δD, and d-excess. This study emphasizes the importance of the high snow accumulation observed at this site in providing valuable information on sub-annual variations in climate and environmental changes through the study of longer ice cores. Sun, 01 Jan 2023 00:00:00 GMT https://repository.kopri.re.kr/handle/201206/14966 2023-01-01T00:00:00Z https://repository.kopri.re.kr/handle/201206/15086 Title: Recent decline in atmospheric Pb deposition and isotopic constraints on changes in source contributions in snow from northwestern Greenland Authors: 이상희; Lee, Khanghyun; 한창희; Han, Yeongcheol; Hong, Sang-Bum; Hur, Soon Do; Lee, Seungmi; Chang, Chaewon; Jung, HyeJin; Moon, Jangil; Claude F. Boutron; 홍성민 Abstract: We present lead (Pb) concentrations and isotope ratios in a continuous series of 38 snow samples from a 1.9-m snow pit, covering the period from winter 2012 to summer 2017, at the East Greenland Ice-core Project (EGRIP) ice core drill site in northwestern Greenland. Pb concentrations were highly variable, ranging from 1.53 to 94.9 pg g？1 (mean value of 10.6 pg g？1), with higher concentrations during winter and spring and lower concentrations during summer and fall. Our results show a substantial reduction in the Pb concentration of ~50% between the 2000s and 2010s, reaching a level close to that observed in the mid-18th century, that is, the time of the Industrial Revolution. Remarkably low radiogenic Pb isotope compositions were observed in our samples compared to previously reported values during the 2000s. The Pb isotope mixing model results indicated a decreasing Chinese contribution from the 2000s onwards, while Europe/Russia emerged as a relatively more important contributor to the anthropogenic Pb input to central Greenland during the corresponding period. Thus, we hypothesized that the reduction in Pb pollution in central Greenland is largely due to a decreasing contribution from Chinese sources in response to the effectiveness of stringent emission control measures in China. Sun, 01 Jan 2023 00:00:00 GMT https://repository.kopri.re.kr/handle/201206/15086 2023-01-01T00:00:00Z