Mesoscale Ocean Processes What role do mesoscale ocean processes play in establishing the mean climate, its variability, and the response to climate forcing? Developing an eddy-resolving global ocean component for CCSM to address these questions. 1.0˚ 0.1˚

Factors influencing the polar amplification of climate change Polar Climate Studies Factors influencing the polar amplification of climate change Shown is the zonally averaged surface air temperature change simulated in a number of coupled models The role of the ocean, sea ice and coupled feedbacks in the climate variability of the southern ocean Shown is the regression of absorbed solar radiation on the leading mode of sea ice variability in CCSM2

Hindcast of the formation and propagation of South Pacific salinity anomalies of 0 = 25.5 from 1966 to 1974. Model results have given insights into the process (late winter vertical mixing below the mixed-layer) that injects positive anomalies onto deep isopycnals downstream (north) of their wintertime surface outcrops (solid contour across ~ 30S). The slow propagation toward the equator offers the possibility of predicting near equatorial anomalies years in advance.

WITH DC (BLUE) WITHOUT DC (BLACK) In CCSM3, the ocean model exchanges information with the coupler once a day. Thus, the diurnal cycle (DC) is not explicitly resolved. Instead, its effects are included in solar heating within the ocean model. The simulations produce a diurnal cycle in vertical mixing in the upper ocean in agreement with observations. The figure shows that the Equatorial Pacific mean SST is about 1C warmer with the DC parameterization than without one, in better agreement with the Reynolds and Smith (1994) climatology. Additionally, NINO3.4 standard deviation improves dramatically (0.81 vs. 1.12 C with and without DC, respectively), matching the observational value of about 0.82 C .

Multi-Century Coupled Carbon/Climate Simulations +2.0 14.1 13.6 -2.0 Surface Temp. Net CO2 Flux (Pg C/yr) year 1000 year 1000 Fully prognostic land/ocn BGC and carbon/radiation Atm-Land CO2 flux: 70 PgC/yr ; Atm-Ocean CO2 flux: 90 PgC/yr  Net Land+ocean CO2 flux: 01 PgC/yr “Stable” carbon cycle and climate over 1000y Baseline for : Projection of climate change on natural modes, Detection & attribution, Future climate projections/fossil fuel perturbations Joint work with UC-Berkeley, WHOI