https://repository.kopri.re.kr/handle/201206/5390 Thu, 05 Mar 2026 10:03:46 GMT 2026-03-05T10:03:46Z https://repository.kopri.re.kr/handle/201206/10960 Title: Very old firn air linked to strong density layering at Styx Glacier, coastal Victoria Land, East Antarctica Authors: Jang, Youngjoon; Hong, Sang-Bum; Buizert, Christo; Lee, Hun-Gyu; Han, Sang-Young; Yang, Ji-Woong; Lizuka, Yoshinori; Hori, Arika; Han, Yeongcheol; Jun, Seong Joon; Tans, Pieter; Choi, Taejin; Kim, Seong-Joong; Hur, Soon Do; Ahn, Jinho Abstract: Firn air provides plenty of old air from the near past, and can therefore be useful for understanding human impact on the recent history of the atmospheric composition. Most of the existing firn air records cover only the last several decades (typically 40 to 55 years) and are insufficient to understand the early part of anthropogenic impacts on the atmosphere. In contrast, a few firn air records from inland sites, where temperatures and snow accumulation rates are very low, go back in time about a century. In this study, we report an unusually old firn air effective CO2 age of 93 years from Styx Glacier, near the Ross Sea coast in Antarctica. This is the first report of such an old firn air age (> 55 years) from a warm coastal site. The lock-in zone thickness of 12.4m is larger than at other sites where snow accumulation rates and air temperature are similar. High-resolution X-ray density measurements demonstrate a high variability of the vertical snow density at Styx Glacier. The CH4 mole fraction and total air content of the closed pores also indicate large variations in centimeter-scale depth intervals, indicative of layering. We hypothesize that the large density variations in the firn increase the thickness of the lock-in zone and, consequently, increase the firn air ages because the age of firn air increases more rapidly with depth in the lock-in zone than in the diffusive zone. Our study demonstrates that all else being equal, sites where weather conditions are favorable for the formation of large density variations at the lock-in zone preserve older air within their open porosity, making them ideal places for firn air sampling. Sun, 01 Sep 2019 00:00:00 GMT https://repository.kopri.re.kr/handle/201206/10960 2019-09-01T00:00:00Z https://repository.kopri.re.kr/handle/201206/10896 Title: Plutonium fallout reconstructed from an Antarctic Plateau snowpack using inductively coupled plasma sector field mass spectrometry Authors: Hwang, Heejin; Hur, Soon Do; Lee, Jeonghoon; Han, Yeongcheol; Hong, Sungmin; Motoyama, Hideaki Abstract: Anthropogenic plutonium (Pu) in the environment is a result of atmospheric nuclear testing during the second half of the 20th century. In this work, we analyzed a 4-meter deep Antarctic Plateau snowpack characterized by a lowsnowaccumulation rate and negligible snowimpurities. These sample conditions enabled us to measure the snowpack Pu fallout by applying inductively coupled plasma sector field mass spectrometry to a few mL of snow melt without purification or preconcentration. Pu concentrations in the reconstructed Pu fallout record for the period after 1956 CE increased and decreased in agreement with past atmospheric nuclear testing. Two peaks and two dips associable with historical events were observed, and the highest peak in 1964(±1) CE approximately coincided with the maximum concentration of non-sea-salt sulfate caused by the Mt. Agung eruption in 1963 CE. Enhanced Pu fallout in the 1970s was attributed the geographical proximity of the Southern Hemispheric nuclear test sites. Our results suggest that by improving the instrumental sensitivity and precision, the potential of the Antarctic ice sheet as an archive of Pu fallout can be further explored and utilized for understanding atmospheric dispersion and for dating ice cores. Sat, 01 Jun 2019 00:00:00 GMT https://repository.kopri.re.kr/handle/201206/10896 2019-06-01T00:00:00Z https://repository.kopri.re.kr/handle/201206/10823 Title: Real-time monitoring of cleanroom laboratories using low cost sensors Authors: Han, Yeongcheol; Jung, HyeJin; Moon, Jangil; Baek, Jongmin; Han, Changhee; Hur, Soon Do Abstract: An air filtration system (AFS) is necessary for laboratories that analyze trace components in natural or artificial samples liable to be contaminated by airborne particulates. In general, an AFS employs multi-stage air filters with a HEPA (high efficiency particulate air) or an ULPA (ultra-low penetration air) filter as the final filter to supply particle-free air to a laboratory. However, using these filters does not guarantee the desired cleanliness of air, and routine assessment of the particle levels in laboratory air is required especially given the potential increase in atmospheric fine particles in Korea. In this context, we have developed a real-time particle monitor (PaMo) using a low cost sensor module and a web based data logger. A temperature and humidity sensor was also included in the PaMo. Two PaMo units have been installed in two cleanroom laboratories for ice core research at the Korea Polar Research Institute. The number of particles larger than 0.3 μm, temperature and relative humidity were monitored from 29th March to 24th June 2018. This real-time monitoring proved that, although the particle concentrations in the room air increased with that in the outdoor air, the AFSs were able to achieve and maintain the cleanliness required for each laboratory. The PaMo will be able to identify particle sources other than the outdoor air, provide a guideline for when to replace filters and notify unexpected AFS failure. We suggest that the PaMo is an easy and effective alternative to expensive particle counters for laboratories that operate AFS. Fri, 01 Feb 2019 00:00:00 GMT https://repository.kopri.re.kr/handle/201206/10823 2019-02-01T00:00:00Z https://repository.kopri.re.kr/handle/201206/10848 Title: Surface Temperature in Twentieth Century at the Styx Glacier, Northern Victoria Land, Antarctica, From Borehole Thermometry Authors: Yang, Ji-Woong; Han, Yeongcheol; Orsi, Anais J.; Kim, Seong-Joong; Han, Hyangsun; Ryu, Yeongjun; Jang, Youngjoon; Moon, Jangil; Choi, Taejin; Hur, Soon Do; Ahn, Jinho Abstract: Reconstruction of the long­term surface temperature history in Antarctica is important for a better understanding of human­induced climate changes, especially since the Industrial Revolution. We present here a surface temperature history spanning the last century at Styx Glacier, located on the eastern coast of northern Victoria Land, which is reconstructed using borehole logging data. Our results indicate that surface temperatures in the 20th century were 1.7 ± 0.4 °C higher than the long term averages over 1600？1900 Common Era, indicating regional warming over the eastern coast of northern Victoria Land. However, we found no evidence for significant warming across the northern Victoria Land since the mid­20th century. A global reanalysis as well as the reconstruction of proxy records demonstrate that the climate in this region was more affected by changes in the Southern Hemisphere Annular Mode than in the Amundsen­Bellingshausen Sea Low. Sat, 01 Sep 2018 00:00:00 GMT https://repository.kopri.re.kr/handle/201206/10848 2018-09-01T00:00:00Z