17:15 〜 18:45
[AOS14-P13] Hypothesis on Volume Transport Increase in Korea Strait based on Annual Sea Level Rise
キーワード：Sea Level Rise, Volume Transport, Steric Effect, ADCP Observation
Kim et al. hypothesized an increase in volume transport in the Korea Strait based on the concurrent increase in water temperature and mean sea level observed by the Korea Hydrographic and Oceanographic Agency (KHOA) in the vicinity of the Korea Strait from 2000 to 2009. Since then, no definitive studies have been reported on the increase in the volume transport through the Korea Strait. However, the observed water temperature (2000-2021) and sea level (1989-2021) in the Korea Strait and East Sea have been found increasing. In particular, the mean sea level rise has rapidly increased at a rate of 2.55~3.53 mm/y in these areas, which cannot be explained by only steric effect due to the increased water temperature. It is a more reasonable interpretation that the sea level rise is due to an increase in the volume transport of warm and salty currents.
If the increase in volume transport is explained by the geostrophic equation without considering the sea level rise in the Korea Strait, the current velocity should increase. However, there have been no reports of an increase in current velocity from direct observations using ADCP (e.g. observations of Camellia) or from various numerical models. Therefore, the increase in volume transport cannot be explained by the geostrophic equation.
Another possible explanation for the increase in the volume transport could be the effect of wind. Although Korea is dominated by monsoons, it is also affected by winds during El Niño and La Niña cycles, which occur every 3 to 4 years. During El Niño, northerly winds prevail in Korea, while during La Niña, southerly winds prevail. Therefore, it can be inferred that the transported volume in the Korea Strait slowly increases annually. However, this study found it challenging to establish a clear correlation between the annually-averaged mean sea level and El Niño (or La Niña) during 1989-2021. This difficulty may be due to the interactions of the PDO (Pacific Decadal Oscillation) and AO (Arctic Oscillation) along with the ENSO (El Niño-Southern Oscillation). Nonetheless, it is evident that the interannual variability of winds is impacting the volume transport in the Korean Strait. However, global sea level rise has a negligible impact on the volume transport in the Korea Strait when compared to its interannual variability. Despite this, it appears to have a consistent influence.
If the increase in volume transport is explained by the geostrophic equation without considering the sea level rise in the Korea Strait, the current velocity should increase. However, there have been no reports of an increase in current velocity from direct observations using ADCP (e.g. observations of Camellia) or from various numerical models. Therefore, the increase in volume transport cannot be explained by the geostrophic equation.
Another possible explanation for the increase in the volume transport could be the effect of wind. Although Korea is dominated by monsoons, it is also affected by winds during El Niño and La Niña cycles, which occur every 3 to 4 years. During El Niño, northerly winds prevail in Korea, while during La Niña, southerly winds prevail. Therefore, it can be inferred that the transported volume in the Korea Strait slowly increases annually. However, this study found it challenging to establish a clear correlation between the annually-averaged mean sea level and El Niño (or La Niña) during 1989-2021. This difficulty may be due to the interactions of the PDO (Pacific Decadal Oscillation) and AO (Arctic Oscillation) along with the ENSO (El Niño-Southern Oscillation). Nonetheless, it is evident that the interannual variability of winds is impacting the volume transport in the Korean Strait. However, global sea level rise has a negligible impact on the volume transport in the Korea Strait when compared to its interannual variability. Despite this, it appears to have a consistent influence.