A sudden bottom‐water formation during the severe winter 2000–2001: The case of the East/Japan Sea

We observed a sudden initiation of bottom‐water formation in the East/Japan Sea associated with a severely cold winter in 2000–2001. An increase in dissolved oxygen concentration as well as decreases in temperature and nutrient concentrations for the bottom waters provides unequivocal evidence that cold, oxygen‐rich and nutrient‐poor surface waters were injected directly to the bottom. Since the conveyor‐belt in the East Sea has been undergoing dramatic change with a complete halt to bottom‐water formation since the mid‐1980s, this sudden episode of bottom‐water formation could easily be detected. Though the amount of bottom water formed was rather small, being only about 0.03% of the volume in the past time, the observation clearly demonstrates that the conveyor‐belt is directly connected to the weather system.