불활성기체 선상분석법을 이용한 아문젠해의 빙하융해수 분포 연구

Abstract

Research background and objectives The light noble gases, helium (He) and neon (Ne), dissolved in seawater, can be useful tracers of freshwater input from glacial melting because the dissolution of air bubbles trapped in glacial ice results in an approximately ten-fold supersaturation. However, the conventional method to determine noble gases is dependent on shore-based mass spectrometric system and very time-consuming processes. The other volatile trace gas, Dimethyl sulfide (DMS), as important precursor of cloud condensation nuclei (CCN), directly affects the radioactive budget and resultant climate change. The oceanic emission is a main natural source of atmospheric DMS. Antarctic polynya, especially, can be a key source region of DMS due to high productivity. However, its observations are evidently lacked due to the limited accessibility of polar ocean. Membrane inlet mass spectrometry (MIMS) technique directly samples analyte gases from the aqueous phase gases in seawater through a semi-permeable membrane. Since this method does not require headspace equilibration, MIMS enables us to make a near-real time, high frequency continuous observation of dissolved gases. During the Southern Ocean cruise (Jan. ~ Feb. 2016), we applied the MIMS for onboard measurements of various dissolved gases in Antarctic seawater on the Korean icebreaker R/V Araon. We have attempted i) to make onboard analysis of 5 noble gases (4Hes in an approximately ten-fold supersaturation. However, the conventional method to determine noble gases is dependent on shore-based mass spectrometric system and very time-consuming processes. The other volatile trace gas, Dimethyl sulfide (DMS), as important precursor of cloud condensation nuclei (CCN), directly affects the radioactive budget and resultant climate change. The oceanic emission is a main natural source of atmospheric DMS. Antarctic polynya, especially, can be a key source region of DMS due to high productivity. However, its observations are evidently lacked due to the limited accessibility of polar ocean. Membrane inlet mass spectrometry (MIMS) technique directly samples analyte gases from the aqueous phase gases in seawater through a semi-permeable membrane. Since this method does not require headspace equilibration, MIMS enables us to make a near-real time, high frequency continuous observation of dissolved gases. During the Southern Ocean cruise (Jan. ~ Feb. 2016), we applied the MIMS for onboard measurements of various dissolved gases in Antarctic seawater on the Korean icebreaker R/V Araon. We have attempted i) to make onboard analysis of 5 noble gases (4He