NASA launched a laser-powered planetary scanning satellite last year, and you can help the project along with a smartphone and a few minutes of your time. ICESat-2 measures elevation from orbit as part of NASA’s climate research, but the agency would like some data from the ground to verify those readings. So, it’s rolled out a new tool in the GLOBE Observer app for iPhone and Android.
ICESat-2 uses an instrument called the Advanced Topographic Laser Altimeter System (ATLAS) to measure elevation from its position 300 miles (500 kilometers) above our heads. ATLAS flashes a 532nm beam of light 10,000 times per second, measuring how long it takes those samples to rebound. That lets NASA, for example, track changes in ice coverage. ICESat-2 isn’t only about ice, though. The name stands for Ice, Cloud, and Land Elevation Satellite-2. The latest GLOBE app update focuses on the “land” part.
One of ICESat-2’s missions is to estimate the health of the world’s forests by tracking the height of the canopy. This is a vital piece of the puzzle because healthy forests soak up a lot of the carbon humans release into the atmosphere. Tom Neumann, a project scientist for ICESat-2 at NASA says it’s an open question how accurate the tree height measurements are from space. You can’t very well send scientists all over the world to measure trees, but a smartphone app can gather data from citizen scientists rather easily.
To get involved, install the GLOBE Observer app on your phone. This isn’t a new app, and it contains tools for several different projects. After creating an account, just find the “GLOBE Trees” tool in the list.
NASA recommends finding a tree that is standing straight up with an easily identifiable top. You should stand 7-25 meters away (25-75 feet) from your chosen tree. The phone will guide you through the process of pointing the phone at the top and base of the tree. Next, count your steps to the base of the tree and input that. The app uses simple geometry from the sensors in your phone to work out the height of the tree.
The app soft-launched a few weeks ago, and NASA has already gotten about 700 measurements from people around the world. The team hopes to get much more data in the coming months.
