  We carry out assessments of the life cycle of Loop Current vortices,
so-called rings, in the Gulf of Mexico by applying three objective (i.e.,
observer-independent) coherent Lagrangian vortex detection methods on
velocities derived from satellite altimetry measurements of sea-surface height
(SSH). The methods reveal material vortices with boundaries that withstand
stretching or diffusion, or whose fluid elements rotate evenly. This involved a
technology advance that enables framing vortex genesis and apocalypse robustly
and with precision. We find that the stretching- and diffusion-withstanding
assessments produce consistent results, which show large discrepancies with
Eulerian assessments that identify vortices with regions instantaneously filled
with streamlines of the SSH field. The even-rotation assessment, which is
vorticity-based, is found to be quite unstable, suggesting life expectancies
much shorter than those produced by all other assessments.
