Methods

An overview of methods for measuring turbulence in the ocean, including from profiling floats and gliders, microstructure sensors on autonomous vehicles, and micro-temperature on CTD profiles.

A method for estimating 26°N overturning from time-varying satellite altimetry and time-averaged boundary profiles of dynamic height.

A model-based evaluation of how the choice of referencing geostrophic velocities at AMOC transport mooring arrays can influence the resultant transport estimate, with a focus on the MOVE latitude of 16°N and the RAPID latitude of 26.5°N.

An overview of the status of the AMOC observing system as of 2019, including arrays in the North and South Atlantic, methodology summary and prognosis for the future.

A demonstration of how GRACE-satellite estimates of ocean bottom pressure can be used to stitch together in situ bottom pressure records at 26°N, alleviating the need to detrend the observed bottom pressure. However, the method does not allow determination of the trend over the full period; if the GRACE trend over the full period (2004-2016) is applied, then it implies a trend in the compensation transports from 26°N which has the opposite sign as the compensation transport derived from the RAPID 26°N mooring array.

Updated methods to estimate turbulence from Seagliders (originally from Beaird et al. 2012), with a demonstration in the northeast Atlantic. The primary addition is to filter by local stratification as observed by the Seaglider. When N is large, this filter should isolate turbulent processes within the inertial subrange. When N is very low, within the surface mixed layer for example, this filtering acts to remove the mean and any trend with respect to depth from the vertical velocity.

Previous modeling and observational studies have established that it is possible to accurately monitor the Atlantic Meridional …

An autonomous underwater vehicle (Seaglider) has been used to estimate marine primary production (PP) using a combination of irradiance …

A statistical relationship between satellite sea surface height (SSH) and observed transports at 26°N is used to build a proxy for the AMOC transport since 1992. The method relies on a strong relationship between (1) the interannual variability of spatially-smoothed SSH at the western boundary of the Atlantic and (2) the RAPID 26°N estimate of upper mid-ocean transport (UMO, top ~1100m) across the Atlantic. Explained variance is very high, but the method assumes stationarity in the relationship between SSH and UMO, which would likely be violated on longer timescales associated with e.g., deep watermass change.

Methodology and error analysis for the RAPID 26°N estimates of the AMOC transport.