Feb 5, 2020

Deep-reaching acceleration of global mean ocean circulation over the past two decades

by
Shijian Hu, Janet Sprintall, Cong Guan, Michael J. McPhaden, Fan Wang, Dunxin Hu, Wenju Cai
,
Science Advances
  • States ocean circulation redistributes Earth’s energy and water masses and influences global climate
  • States that under historical greenhouse warming, regional ocean currents show diverse tendencies, but whether there is an emerging trend of the global mean ocean circulation system is not yet clear
  • Shows a statistically significant increasing trend in the globally integrated oceanic kinetic energy since the early 1990s, indicating a substantial acceleration of global mean ocean circulation
  • Finds the increasing trend in kinetic energy is particularly prominent in the global tropical oceans, reaching depths of thousands of meters
  • Finds the deep-reaching acceleration of the ocean circulation is mainly induced by a planetary intensification of surface winds since the early 1990s
  • Finds that, although possibly influenced by wind changes associated with the onset of a negative Pacific decadal oscillation since the late 1990s, the recent acceleration is far larger than that associated with natural variability, suggesting that it is principally part of a long-term trend