Ocean bottom pressure seasonal cycles and decadal trends from GRACE Release-05: Ocean circulation implications

摘要: [1] Ocean mass variations are important for diagnosing sea level budgets, the hydrological cycle, global energy budget, and ocean circulation variability. Here seasonal cycles decadal trends of from January 2003 to December 2012, both regional, analyzed using GRACE Release-05 data. The trend flux into approaches 2 cm decade−1 in equivalent rise. Regional similar magnitude, with North Pacific, South Atlantic, Indian oceans generally gaining other regions losing mass. These suggest a spin-down Pacific western boundary current extension Antarctic Circumpolar Current Atlantic oceans. average cycle is about 1 amplitude, maximum early October volume fluxes out reaching 0.5 Sv (1 Sv = 1 × 106 m3 s−1) when integrated over area here. patterns change have typical amplitudes 1–4 cm, include maxima subtropics minima subpolar hemispheric winters. subtropical gains losses winter spin-up gyres, hence extensions. Seasonal these currents order 10 Sv, but since associated depth-averaged only 0.1 s−1, they would be difficult detect situ oceanographic instruments.