Surprising Resilience of the Madden-Julian Oscillation to Extreme Climate Cooling in the Superparameterized Community Atmosphere Model.

Friday, 19 December 2014
Michael S Pritchard, University of California Irvine, Irvine, CA, United States and Da Yang, University of California Berkeley, Berkeley, CA, United States
We test the hypothesis that radiative convective equilibrium (RCE) self-aggregation is a good metaphor for the maintenance of the Madden-Julian Oscillation by imposing extreme cooling in the Superparameterized Community Atmosphere Model (SPCAM) v. 3.0 in a uniform SST configuration. The expectation is that – like RCE self-aggregation – SPCAM's simulated MJO should shut down at sea surface temperatures significantly less than 25 degrees Celsius. Remarkably, the MJO in SPCAM is resilient to extreme cooling down to one degree Celsius. With cooling, the simulated MJO becomes more barotropic and its zonal wavelength decreases. The amplitude decrease and horizontal scale contraction are consistent with the theoretical prediction from Yang and Ingersoll (2014, GRL).