Kurtz: For this Photon Phriday, we're looking at two satellite tracks in the Arctic Ocean over the sea ice.

And we're looking at the heights of the cracks, so the ocean surface heights within those cracks. NASA and ESA both launched satellites that are able to measure how thick the Arctic ice cover is. ESA has launched CryoSat-2, which is a radar altimeter. Radar will penetrate through the snow surface and so it sees something slightly different than a laser, which ICESat-2 has which will see the top of the snow surface. So they're able to measure the ice thickness and the heights in a different way, but now that the orbits are aligned, we're getting an entirely different measurement concept. So both are trying to measure how thick the ice is in the same way. Every 20 orbits of ICESat-2 now overlaps with CryoSat-2. But also by looking at the differences, we're able to measure how deep is that snow, and then by combining the measurements get a better understanding of how thick the ice is. Bagnardi: It's not just a matter of aligning the two orbits of the two satellites in space, which is already a huge endeavor, but since we want to blend together the data from the two missions to improve and better understand the accuracy of the measurements themselves of ice and sea surface. We need to make sure that these data sets are aligned at the Earth's surface level as well. And when I mean aligned, I mean to the down to the centimeter level. Kurtz: Checking up on the the health of the Arctic sea ice is very important. It's been decreasing a lot in the last few decades, and it's trending towards a ice-free summers in the Arctic. And so being able to understand what's driving those processes is very important, and that's what this new data set will allow us to do.