Sensitivity of Modeled Dynamics to Atmosphere and Ocean Resolution in CESM Aurthors, NCAR CGD CESM using CAM5-SE coupled to POP2 at high (hr) and standard (sr) resolutions • hr atmosphere, hr ocean: ne-120 (~0.25 deg), t-12 (~0.1deg) • hr atmosphere, sr ocean: ne-120 (~0.25 deg), gx1v6 (~1.0 deg) • sr atmosphere, sr ocean: ne-30 (~1.0 deg), gx1v6 (~1.0 deg) Motivation o Surface temperature reaches quasi-equillibrium in hr atm, hr ocn & sr atm, sr ocn; hr atm, sr ocn still warming o TOM EF > 0 and trending down for all. End of run: hr atm, hr ocn (~0.3Wm -2 ) < sr atm, sr ocn (~0.5Wm -2 ) < hr atm, sr ocn (~0.6Wm -2 ) text... Experiment Descriptions Summary and discussion hr atm, hr ocn Surface Temperature hr atm, sr ocn sr atm, sr ocn TOM Energy Flux Pot. Temp Anom from IC Transient Behavior SST (obs. HadISST 1999-2008) hr atm, hr ocn hr atm, sr ocn sr atm, sr ocn Precip (obs. GPCP 1979-2009) o C mm day -1 Annual Mean Bias o C Observations Surface Stress (obs. ERS 1992-2000) mm day -1 Nm -2 Nm -2 o Global mean and rms SST bias is... o Precipitation biases... o Wind stress... ENSO Variability still drifting at surface! hr atm, hr ocn hr atm, sr ocn sr atm, sr ocn Nino 3.4 Power Spectra Gray - HadISST Ann SST EQ Pacific Observations o C SLP CI: 2hPa SST Climatology DJF Comp. SST, T air , SLP o hr atm, hr ocn has better depiction of SST compared to hr atm, sr ocn & sr atm, sr ocn o ...and better zonal SST gradient compared to sr atm, sr ocn decreased ocn res decreased ocn & atmos res decreased atmos res Red – Reynolds and Smith o Shape and amplitude of Nino 3.4 power specra in hr atm, hr ocean resembles obs - hr atm, sr ocn & sr atm, sr ocn have too much variance and are too periodic o SLP tele-connection amplitude is degraded compared to hr atm, sr ocn & sr atm, sr ocn however reasons are unclear Winter Mean MLD Bias (obs. Reynolds and Smith) m