[18p-D62-1~17] CS.1 Code-sharing Session of 2.3 & 7.4

5:45 PM - 6:00 PM JST(8:45 AM - 9:00 AM UTC)Presentation by Applicant for JSAP Young Scientists Presentation AwardEnglish Presentation

[18p-D62-16] Temporal Changes of Iodine-129 in the Canada Basin Over the Past Decade

〇(P)Yuanzhi Qi¹, Takeyasu Yamagata¹, Hiroyuki Matsuzaki¹, Hisao Nagai², Yuichiro Kumamoto³, Qiuyu Yang¹, Xinru Xu¹ (1.The Univ. of Tokyo, 2.Nihon Univ., 3.JAMSTEC)

Keywords:

Iodine-129,Canada Basin

The Arctic, known for its high sensitivity to global climate change, has experienced a temperature increase surpassing four times the global average rate since the industrial era began. This warming trend has coincided with the northward encroachment of warmer and saltier Atlantic waters into the Arctic Ocean, a phenomenon termed "atlantification". These changes have led to significant reductions in Arctic sea ice and alterations in seawater thermohaline structure, potentially impacting Arctic ocean currents. Understanding the response mechanisms of these currents to climate change is crucial for comprehending and addressing the broader impacts of global warming. Iodine-129 (¹²⁹I), released in substantial quantities directly into the North Atlantic from nuclear fuel reprocessing plants (NFRPs), is transported into the Arctic via the Fram Strait and Barents Sea, making it an ideal tracer for tracking Arctic currents. While numerous studies have utilized ¹²⁹I to investigate ocean currents in the Eurasian Basin, research in the Canada Basin, which also features complex current patterns, remains limited.
This study presents a decade-long analysis of temporal changes in ¹²⁹I concentrations at two stations (NAP, 74.5 ºN, 162.0 ºW; CB, 72.5 ºN, 155.0 ºW) within the Canada Basin from 2013 to 2023. Our findings reveal a diminishing influence of Atlantic water on the surface of the Canada Basin over this period. In the early 2010s, ¹²⁹I concentrations in the intermediate layer at both stations remained similar, indicating a shared source. However, by the late 2010s, the concentration of ¹²⁹I in the intermediate layer at the NAP station significantly surpassed that at the CB station, suggesting a shift in ocean currents potentially linked to changes in the Arctic Oscillation and atlantification.