The world has lost over 2,000,000 square miles of tree cover since 2000—equivalent to the total land area of India and Mexico combined. Of that total, around 36% is estimated to be permanent deforestation. Much of this forest loss is driven by agriculture, wildfires, and logging. For those in charge of managing our planet’s vast forests, tracking each tree felled is a nearly impossible task. But not catching new logging operations, illegal deforestation, or the onset of forest fires can lead to polluted waters, habitat degradation, and out-of-control blazes. That’s where the global land change monitoring system DIST-ALERT comes in.
DIST-ALERT provides rapid alerts each time vegetation is disturbed. The idea for a global vegetation monitoring system came from a Satellite Needs Working Group (SNWG) survey highlighting federal agencies’ need for frequent, detailed data on land surface changes. To meet this need, Observational Products for End-Users from Remote Sensing Analysis (OPERA) at NASA/Jet Propulsion Laboratory (JPL) partnered with the Global Land Analysis and Discovery (GLAD) lab at University of Maryland to develop the tool. Using DIST-ALERT, land managers can identify when forests—and other vegetated surfaces—change, allowing researchers to spot shifting agricultural patterns, city expansion, and more.
DIST-ALERT is based on Harmonized Landsat and Sentinel-2 Version 2.0, which combines data from five satellites. Amy Pickens, an assistant research professor at the University of Maryland, developed DIST-ALERT with the other members of the GLAD team using HLS because its global average revisit frequency of observations—every 1.4 days—is ideal for tracking land …