Impacts of Regional Mixing on Circulations in the Subtropical and Tropical Pacific Ocean

1. Impacts of Regional Mixing on Circulations in the Subtropical and Tropical Pacific Ocean R. Furue1, Y. Jia1, J.P. McCreary1, K.J. Richards1, N. Schneider1, P. Müller2, B.D. Cornuelle3, N. Martinez Avellaneda3, and D. Stammer4 1IPRC, 2U. Hawaii, 3SIO, 4U. Hamburg Figure 1. The model domain and each subregion, in which diapycnal diffusivity is separately increased from a background value of 0.1 × 10-4 to 0.5 × 10-4 m2/s. Figure 2. Salinity anomaly (shading, PSU) arising from Experiment SE compared to the control run (CTL) and Montgomery streamfunction from CTL on the 24.6 σθ surface at year 20. An eddy-permitting model of the tropical and subtropical Pacific (Figure 1) is spun up under climatological forcing. In separate experiments, the background diapycnal diffusivity within spatially distinct subregions in Figure 1 is then increased. The impacts of those changes are assessed and the processes to account for them diagnosed. Figure 2 shows the salinity anomaly of Experiment SE (Figure 1) on a shallow isopycnal that intersects the core of the Equatorial Undercurrent. Although the dynamical anomaly (such as density) is weak outside the latitude band of SE (not shown), the salinity anomaly on isopycnals (“spiciness”), being a passive tracer, is advected to the equator and upwells in the eastern equatorial Pacific, affecting sea-surface temperature there.