Global Response to Fresh Water Release under Different Climate States
Abstract
Massive discharge or melt water of Ice sheet to ocean is one of the cause thought to be responsible for the climate change such as Younger Dryas or Heinrich events. There is not yet a consensus, however, in the thermal response to fresh water release in North Atlantic in global models and/or the paleoclimatic data in the region far from North Atlantic. Here we ran several sensitivity experiments using a coupled atmosphere and ocean GCM (MIROC3.2) with 500 years water hosing of 0.1 Sv in the North Atlantic which is the same amount and position as CMIP/PMIP protocol under different basic states; O`Modern HosingO-L in modern climate with the pre-industrial condition and O`LGM hosingO-L under LGM condition (ice sheet, orbital parameter, greenhouse gases conditions in 21ka as PMIP2). The results show a much larger cooling response in North Atlantic through a stronger sea ice ocean- atmosphere feedback and in the LGM hosing than in Modern hosing. What is surprising is the almost opposite sign of response in the Southern Ocean especially in the last phase after 400 years water release, resulting in warming for LGM-hosing case and cooling for Modern hosing case. The sensitivity tests show clearly that the bipolar response to fresh water release depends highly on the basic climate state and stages.
- Publication:
-
AGU Fall Meeting Abstracts
- Pub Date:
- December 2006
- Bibcode:
- 2006AGUFMPP21A1671A
- Keywords:
-
- 4900 PALEOCEANOGRAPHY (0473;
- 3344);
- 4901 Abrupt/rapid climate change (1605);
- 4928 Global climate models (1626;
- 3337);
- 4938 Interhemispheric phasing