[nisegami]

I want to imagine that lakes might be a good starting point for this comparison. For example, 600,000 km^3 is roughly 50 Lake Superiors. This is still context dependent, but I can at least pull up a map and look at the size of Lake Superior to get a feel for it.

[marginalia_nu]

Lakes have a sort of nebulous depth though. They're probably a better measuring stick for area than volume.