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Changes in mixed layer depth under climate change projections in two CGCMs.
- Source :
- Climate Dynamics; Aug2009, Vol. 33 Issue 2/3, p199-213, 15p, 1 Diagram, 1 Chart, 3 Graphs, 6 Maps
- Publication Year :
- 2009
-
Abstract
- Two coupled general circulation models, i.e., the Meteorological Research Institute (MRI) and Geophysical Fluid Dynamics Laboratory (GFDL) models, were chosen to examine changes in mixed layer depth (MLD) in the equatorial tropical Pacific and its relationship with ENSO under climate change projections. The control experiment used pre-industrial greenhouse gas concentrations whereas the 2 × CO<subscript>2</subscript> experiment used doubled CO<subscript>2</subscript> levels. In the control experiment, the MLD simulated in the MRI model was shallower than that in the GFDL model. This resulted in the tropical Pacific’s mean sea surface temperature (SST) increasing at different rates under global warming in the two models. The deeper the mean MLD simulated in the control simulation, the lesser the warming rate of the mean SST simulated in the 2 × CO<subscript>2</subscript> experiment. This demonstrates that the MLD is a key parameter for regulating the response of tropical mean SST to global warming. In particular, in the MRI model, increased stratification associated with global warming amplified wind-driven advection within the mixed layer, leading to greater ENSO variability. On the other hand, in the GFDL model, wind-driven currents were weak, which resulted in mixed-layer dynamics being less sensitive to global warming. The relationship between MLD and ENSO was also examined. Results indicated that the non-linearity between the MLD and ENSO is enhanced from the control run to the 2 × CO<subscript>2</subscript> run in the MRI model, in contrast, the linear relationship between the MLD index and ENSO is unchanged despite an increase in CO<subscript>2</subscript> concentrations in the GFDL model. [ABSTRACT FROM AUTHOR]
Details
- Language :
- English
- ISSN :
- 09307575
- Volume :
- 33
- Issue :
- 2/3
- Database :
- Complementary Index
- Journal :
- Climate Dynamics
- Publication Type :
- Academic Journal
- Accession number :
- 41677573
- Full Text :
- https://doi.org/10.1007/s00382-009-0530-y