"Sea level rise is two things," said Dr. Alex S. Gardner, a JPL research scientist working on the project. "It is the ocean warming, because warm water takes up more volume than cold water. And it is ice from the continents that ends up in the ocean. If you want to know what sea level rise will be in the future, you have to know how much ice will go into the ocean. Once you answer that question, you know how much sea level will rise."
In this effort, having high-quality images from the Landsat 8 satellite is important. But it isn't the key that unlocks the answer. "The satellite is fantastic," says Gardner. "But it was never designed to map glacial flow. The most important thing about this mission is continuity."
The new Landsat 8 has a radiometric capability, which means it can resolve the greyscale in satellite images with much finer detail, giving scientists a crystal-clear image of how the ice is moving. And it collects an enormous quantity of images, so many that just downloading them to earthbound computers created a bottleneck.