The Global Patterns of Interannual and Intraseasonal Mass Variations in
the Oceans from GRACE and GRACE Follow-On Records
We decompose the monthly global Ocean Bottom Pressure (OBP) from
GRACE(-FO) mass concentration solutions, with trends and seasonal
harmonics removed from the signal, to extract 23 significant regional
modes of variability. The 23 modes are analyzed and discussed
considering Sea-Level Anomalies (SLA), Wind Stress Curl (WSC), and major
climate indices. Two-thirds of the patterns correspond to extratropical
regions and are substantially documented in other global or regional
studies. Over the equatorial band, the identified modes are
unprecedented, with an amplitude ranging between 0.5 and 1 centimeter.
With smaller amplitude than extratropical patterns, they appear to be
less correlated with the local SLA or WSC; yet, they present
significantly coherent dynamics. The Pacific Ocean modes show
significant correlations with the Pacific Decadal Oscillation (PDO) and
El Niño Southern Oscillation (ENSO).