Coherent signals between the RAPID array and satellite altimetry

The RAPID array uses standard observational techniques — moored instruments that measure conductivity, temperature and pressure, as well as bottom pressure recorders — to measure density and pressure gradients across the North Atlantic, from which one can readily calculate the basin overturning circulation [1] and heat transport [2]. Although straightforward to implement, it is less obvious how to describe the observed low-frequency basin-wide signals in terms of specific dynamic processes. We approach this goal by decomposing full-depth observations in terms of vertical modes, which are then compared and contrasted with sea surface height (SSH) from altimetry. More specifically, we investigate how well SSH can be used to reconstruct 1) full water-column density perturbations, 2) geostrophic transport fluctuations between moorings, and 3) the basin-wide overturning signal.