I want to know the answer to the following question:
What device was used to produce the measurements of sea level change on Tuvalu?
All the background I'm provided with is that "The 2011 report of the Pacific Climate Change Science Program published by the Australian Government, concludes: "The sea-level rise near Tuvalu measured by satellite altimeters since 1993 is about 5 mm (0.2 in) per year."". Is that enough to answer the question?