Data Processing:

The data consist of processed tracks from 137 RAFOS float trajectories collected for the Overturning in the Subpolar North Atlantic Program (OSNAP) between June 2014 and January 2019.

The floats were tracked in Matlab using the ARTOA3 software package. Erroneous spikes in the temperature and pressure data were removed. Time drifts in the sound sources were calculated and applied. Before starting to track the data, time differences in the times-of-arrival (TOAs) were corrected. Any missing TOA data were then interpolated using a variable width (usually 10-day) cubic spline filter. A least-squares method was used for tracking if more than two TOAs were available. Sound velocity was estimated using the Del Grosso equation, which is based on the recorded temperature and pressure of the float.

The final data variables are: time, latitude, longitude, pressure, temperature, u-velocity, v-velocity, and the following flag values:
0 = no_sound_sources_used
1 = one_sound_source_used
2 = two_sound_sources_used
3 = three_sound_sources_used
4 = four_sound_sources_used
5 = five_sound_sources_used
0 = no_data

(Created August 11, 2021, ABA/ALR/HHF, WHOI)