Evidence for physical Changes in the Circulation from the 80s to the 90s

1
Evidence for physical Changes in the Circulation
from the 80s to the 90s

• LuAnne Thompson
• Curtis Deutsch
• Steve Emerson

2
Sources for Physical Changes

• Wind Changes
• Changes in Buoyancy forcing

3
Changes in the Sverdrup Circulation
4
Changes in Ventilation of 26.6 ispycnal
5
AOU changes on 26.2
160W, 150W, 45N
150W, 45N, 40N, 35N, 30N
6
Conclusions

• Sverdrup circulation has changed in response to
  changes in the wind, with the recirculation
  region increasing and eastern Pacific decreasing
  in strength.
• Outcrop area and ventilation has also changed for
  26.6 layer.
• AOU anomalies propagate from the west to east
  from the outcrop region and from North to South,
  following the circulation with changes occuring
  more rapidly near the outcrop.

7
Outstanding questions

• Are the anomalies biggest on 26.6 because it is
  the deepest isopycnal that outcrops in the North
  Pacific?
• What is the balance of circulation changes versus
  ventilation changes? freshwater versus thermal
  forcing?
• Do the changes in the AOU reflect global warming?
  
• What is the relationship between changes in AOU
  and changes in surface oxygen flux? Carbon flux?