4:00 PM - 4:15 PM
[AOS09-09] Changes and future predictions of Oyashio Intermediate Water: Weakened overturning vs. enhanced tidal mixing
Keywords:Oyashio, Climate change, Sea of Okhotsk, Western subarctic Pacific, 18.6 year tidal cycle, Pacific overturning
Here, we created seasonal climatologies of water properties to understand how the long-term trend (~50 years) and 18.6-year tidal cycle affect the Oyashio Intermediate Water (OYW). We found that the “recipe” of OYW is modified mainly in winter via decreased OSIW outflow over the trend and increased (decreased) outflow in high-tide (low-tide) years. Based on this, we provide a 20-year prediction of OYW temperature and mixing ratio. We predict that the opposite effects of the trend and high tide in the 2020s will lead to stagnation of the OYW properties, followed by accelerated warming in the 2030s (low-tide years). Besides, we found that OYW temperature will increase by 1 °C, and the mixing ratio of OSIW in OYW will decrease by 50% between 1960 and 2040, which might greatly impact biological productivity and carbon drawdown in the North Pacific.