Satellite thermal sensors can now reveal which blocks bake hottest after sundown, and city planners are using this data to reprioritize projects. As Los Angeles Bureau of Street Services Chief Sustainability Officer Greg Spottsnotes, “all of our hardscape – our transportation infrastructure – is radiating heat into our neighborhoods even at 4 in the morning,” a phenomenon that is “detectable from space”.
In effect, this implies that dark asphalt roadways, parking lots, and rooftops are represented as bright red on high-resolution thermal charts. Now, cities from Los Angeles to Chicago are harnessing a combination of these satellite maps and ground measurements to tackle the worst hotspots.
In Prince George’s County, Maryland, NASA scientists used Landsat images to find that the county landfill hadbecomethe “largest area of intensifying/persistent/historical warming” on public land—and city engineers have since shifted mitigation plans (adding trees, bioswales, reflective covers) to cool that site first.
New space sensors are only making this easier. NASA’s ECOSTRESS instrument on the ISS, for example, collected imagery of Los Angeles in 2018, showing surface‐temperature variations at the sub‑block scale. It measured midday temperatures up to 147.3°F on a hot August afternoon—”hot enough to fry an egg” on a parking lot—and traced how roofs and roads cool off overnight.
Satellite thermal sensors can now reveal which blocks bake hottest after sundown, and city planners are using this data to reprioritize projects. As Los Angeles Bureau of Street Services Chief Sustainability Officer Greg Spottsnotes, “all of our hardscape – our transportation infrastructure – is radiating heat into our neighborhoods even at 4 in the morning,” a phenomenon that is “detectable from space”.
In effect, this implies that dark asphalt roadways, parking lots, and rooftops are represented as bright red on high-resolution thermal charts. Now, cities from Los Angeles to Chicago are harnessing a combination of these satellite maps and ground measurements to tackle the worst hotspots.
In Prince George’s County, Maryland, NASA scientists used Landsat images to find that the county landfill hadbecomethe “largest area of intensifying/persistent/historical warming” on public land—and city engineers have since shifted mitigation plans (adding trees, bioswales, reflective covers) to cool that site first.
New space sensors are only making this easier. NASA’s ECOSTRESS instrument on the ISS, for example, collected imagery of Los Angeles in 2018, showing surface‐temperature variations at the sub‑block scale. It measured midday temperatures up to 147.3°F on a hot August afternoon—”hot enough to fry an egg” on a parking lot—and traced how roofs and roads cool off overnight.
