https://repository.kopri.re.kr/handle/201206/11554 2026-04-21T08:47:11Z 2026-04-21T08:47:11Z Kang, Myounghee Fajaryanti, Rina Son, Wuju Kim, Jeong-Hoon La, Hyoung Sul https://repository.kopri.re.kr/handle/201206/11822 2022-03-24T07:14:53Z 2020-11-01T00:00:00Z

Title: Acoustic Detection of Krill Scattering Layer in the Terra Nova Bay Polynya, Antarctica Authors: Kang, Myounghee; Fajaryanti, Rina; Son, Wuju; Kim, Jeong-Hoon; La, Hyoung Sul Abstract: Krill play a crucial role in the transfer of energy in the marine food web, connecting primary producers and the upper trophic levels in the Terra Nova Bay polynya (TNBP), which is part of the Ross Sea marine protected area. Despite the substantial ecological importance of krill, there are few studies on their distribution and abundance in the TNBP. An acoustic survey was conducted on 7-14 January 2019 in the TNBP, Ross Sea, using a Simrad EK60 echosounder (38 and 120 kHz) aboard the icebreaker RV Araon. The most commonly used range of the difference of the mean volume backscattering strength (MVBS) (2-16 dB) was applied to distinguish krill. The acoustic data (120 kHz) were extracted to examine the krill distribution characteristics. The study area was divided into low-value areas and high-value areas based on the third quartile of the nautical area scattering coefficient. The results showed that the krill aggregations were distributed in three layers at depths of 0-30 m, 70-110 m, and 270-300 m. The interpolated environmental parameters associated with the backscattering strength were compared. High-value areas of krill coincided with relatively low temperature, low salinity, and high chlorophyll, although very weak correlations were found. The primary goal of this study was to understand the vertical and horizontal distributions of krill acoustic biomass and to relate the observed patterns to the dominant environmental conditions.

2020-11-01T00:00:00Z Yan, Jinpei Jung, Jinyoung Lin, Qi Zhang, Miming Xu, Suqing Zhao, Shuhui https://repository.kopri.re.kr/handle/201206/11814 2022-03-24T07:14:52Z 2020-11-01T00:00:00Z

Title: Effect of sea ice retreat on marine aerosol emissions in the Southern Ocean, Antarctica Authors: Yan, Jinpei; Jung, Jinyoung; Lin, Qi; Zhang, Miming; Xu, Suqing; Zhao, Shuhui Abstract: Sea ice retreat in the polar region is expected to increase the emissions of sea salt aerosols and biogenic gases, which may significantly impact the climate by increasing cloud condensation nuclei (CCN) population and changing solar radiation. In this study, aerosol compositions were measured at high-time-resolution (1 h) with an in-situ gas and aerosol composition monitoring system in polynya regions of the Southern Ocean (SO) to access the effects of sea ice concentrations on the sea salt aerosol (SSA) and secondary biogenic aerosol (SBA) in the SO. SSA emissions increased bymore than 30% as sea ice concentration decreased from85% to 29%.However, SSA emissions did not increase monotonically as the sea ice concentration decreased. The highest SSA concentration occurred in drifting sea ice region. Sea ice melting increased SBA concentrations by enhancing the air-sea exchanges of SBA precursor gases and the release of algae from sea ice. Positive correlations between SSA and wind speed were present in different sea ice regions, while SBA didn't reveal an obvious correlation with wind speed in the SO. The impact of wind speed on the SSA emissions were very different, Higher slope value of 41.83 and 35.81 were present in the DSI and SIF region, while the value was only about 16.74 in the SIC region. The results extended the knowledge of the effect of future sea ice retreat on marine aerosol emissions and potential climate changes in the polar region.

2020-11-01T00:00:00Z Ju, YeoJin Lee, Seong-Sun Kaown, Dugin Lee, Kang-Kun Gilfillan, Stuart M.V. Hahm, Doshik Park, Keyhong https://repository.kopri.re.kr/handle/201206/11871 2022-03-24T07:14:52Z 2020-07-01T00:00:00Z

Title: Noble gas as a proxy to understand the evolutionary path of migrated CO2 in a shallow aquifer system Authors: Ju, YeoJin; Lee, Seong-Sun; Kaown, Dugin; Lee, Kang-Kun; Gilfillan, Stuart M.V.; Hahm, Doshik; Park, Keyhong Abstract: To provide confidence in the safety of a carbon capture and storage (CCS) project, researchers have focused on developing monitoring techniques to trace the unlikely, but potentially possible, migration of CO2 from a deep reservoir. Among the various techniques, noble gas tracing is a beneficial approach, owing to the unique noble gas fingerprints present in injection fluids, the deep reservoir, and the shallow aquifer above the storage area. However, the value of this approach has been limited to demonstrations in a natural analogue CO2 -rich reservoir and an artificial injection test site. Therefore, further efforts are required to link those valuable observations to an actual CCS site. In this study, we outline how to use these tracers for actual monitoring work in a shallow aquifer system. First, two artificial injection tests were performed using He, Ar, Kr, and SF 6 to understand the behavior of the leaked plume in the shallow aquifer system. In both tests, the noble gas ratio remarkably changed with the solubility -controlled process and the mixing process. To extend and link the valuable findings from the artificial injection tests to an actual CO2 leakage event, we performed a leakage simulation using data from a real CO2 injection site, i.e., the Weyburn -Midale site. This simulation suggested that combinations of He-4 with other heavier noble gases can be used to monitor CO2 leakage, as they allow us to separate and explain the major interactions governing the migration of the leaked plume in the shallow aquifer system. Additionally, although the high CO2 density of a dissolved plume is known to add uncertainty in quantitative approaches, the influence of those effects was negligible when compared to the errors arising from the wide variation in the noble gas fingerprints in the leaked CO2 . This study, therefore, provides insight into the evolutionary path of the migrated CO2 plume in the shallow aquifer system and to the results can be used to inform the tracing of a leakage source within a shallow aquifer despite various mechanisms complicating the plume distribution.

2020-07-01T00:00:00Z Yan, Jinpei Zhang, Miming Jung, Jinyoung Lin, Qi Zhao, Shuhui Xu, Suqing Chen, Liqi https://repository.kopri.re.kr/handle/201206/11812 2022-03-24T07:14:53Z 2020-07-01T00:00:00Z

Title: Influence on the conversion of DMS to MSA and SO42？ in the Southern Ocean, Antarctica Authors: Yan, Jinpei; Zhang, Miming; Jung, Jinyoung; Lin, Qi; Zhao, Shuhui; Xu, Suqing; Chen, Liqi Abstract: Dimethyl sulfide (DMS), methanesulphonic acid (MSA) and sulfate (SO42-) were measured simultaneously at high-time resolution in the Southern Ocean (SO) during February and March 2018, to characterize the conversion of DMS to MSA and SO42- in the marine atmosphere. DMS concentrations ranged up to similar to 10890.5 ng m(-3) (with an average of 899.8. 957.9 ng m(-3), representing the standard deviation), which were much higher than the MSA concentrations (with an average of 30.6. 16.8 ng m 3) and SO42- concentration (148.1. 32.5 ng m(-3)) in the aerosol phase. The spatial distribution of MSA was different from the distribution of DMS. The ratio of MSA to DMS (RM) ranged up to similar to 0.31, with an average of 0.044. 0.045. RM value decreased dramatically as DMS concentration increased, when DMS concentration was below 1000 ng m(-3). The effects of temperature and relative humidity (RH) on RM were mostly negligible, indicating that neither DMS concentration, nor RH and temperature was the key parameter for the conversion of DMS to MSA in the SO. Ratios of nss-SO42- to DMS (R-S) were used to estimate the conversion of DMS to SOv. The calculated RS with mean Rp (the ratio of MSA to nss-SOv) value correlated well with the observed RS, which provided an useful method to estimate the biogenic SO42- from the oxidation of DMS in the marine atmosphere, as biogenic SO42- levels can be calculated with Rs and DMS concentrations. The estimated biogenic SO42- levels ranged up to 163.8 ng m(-3), with an average of 47.1 +/- 30.2 ng m 3 in the SO during the cruise. The results extend the knowledge of the conversion of DMS to MSA and SO42- in the marine atmosphere.

2020-07-01T00:00:00Z