Attribution and Impacts of Upper-Ocean Biases in CCSM3

摘要: The largest and potentially most important ocean near-surface biases are examined in the Community Climate System Model coupled simulation of present-day conditions. They attributed to problems component models or atmosphere, both. Tropical sea surface salinity (SSS) associated with precipitation errors, striking being a band excess rainfall across South Pacific at about 8°S. Cooler-than-observed equatorial temperature (SST) is necessary control catastrophic positive feedback, involving along equator. strength wind-driven gyres interbasin exchange reasonable agreement observations, despite generally too strong winds. However, winds drive far much transport through Drake Passage [190 Sv (1 10 6 m 3 s 1 )], but little effect on SST SSS. Problems width, separation, location western boundary currents their extensions create large correlated SSS midlatitudes. Ocean model deficiencies suspected because similar signals seen uncoupled solutions, there no evidence serious remote impacts. seasonal cycles not well represented, numerical experiments suggest that these initiated by coupling either both wind components. mean develop eastern boundaries subtropical gyres, overall response found be linear. In Atlantic, advect tropical basin. Significant responses northwest Indian Ocean, locally where net result loss an identifiable Atlantic intertropical convergence zone, which can regained controlling coastal temperatures salinities. Biases off America Baja California shown significantly degrade Pacific, subsurface properties sides equator, cycle Pacific. These extend beyond reach currents, so connections via atmosphere implicated. Other experimental results indicate local atmospheric forcing only part problem boundaries, representation upwelling another likely contributor.