Previous optical clocks were able to measure gravitational time dilation from under a meter of altitude. I'll bet that this one measures it to the order of a c

Previous optical clocks were able to measure gravitational time dilation from under a meter of altitude. I'll bet that this one measures it to the order of a centimeter. And it isn't just height that is going to have an impact. Any major mass shift affects it. For example in Scandinavia, melting ice in Greenland and rising land will combine to make ultra-precise clocks there run measurably faster over time relative to where they started.