Landsat at 50: How satellites revolutionized the means we gaze — and shield — the pure world

Landsat at 50: How satellites revolutionized the means we gaze — and shield — the pure world


The river looks like light beige wiggly lines twisting through the dark green forested landscape.



A river meanders via the Amazon Basin, viewed from Landsat.
(Describe credit: NASA)

This article became originally printed at The Conversation. (opens in new tab) The newsletter contributed the article to Fetch 22 situation.com’s Expert Voices: Op-Ed & Insights (opens in new tab).

Stacy Morford (opens in new tab), Associated Press national editor and order govt reporter.

Fifty years within the past, U.S. scientists launched a satellite tv for computer that dramatically modified how we gaze the field.

It captured images of Earth’s floor in minute part, exhibiting how wildfires burned landscapes, how farms erased forests, and lots of utterly different ways americans were altering the face of the planet.

The first satellite tv for computer in the Landsat sequence (opens in new tab) launched on July 23, 1972. Eight others adopted, offering the identical views so adjustments would be tracked over time, but with an increasing number of extremely efficient devices. Landsat 8 (opens in new tab) and Landsat 9 (opens in new tab) are orbiting the planet as of late, and NASA and the U.S. Geological Stare are planning a new Landsat mission (opens in new tab)

Connected: Dangle a just appropriate time 50 years of Landsat with these excellent images (gallery)

The footage and records from these satellites are extinct to trace deforestation and altering landscapes round the field, locate metropolis heat islands, and see the affect of new river dams, amongst many replacement projects. On the total, the implications aid communities acknowledge to risks that won’t be obvious from the ground.

Here are three examples of Landsat in motion, from The Conversation’s archive.

Tracking adjustments within the Amazon

Dam across the Amazon river.

The Belo Monte Dam’s constructing, confirmed right here in 2012, flooded land and adjusted the river. (Describe credit: Mario Tama/Getty Pictures)

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When work began on the Belo Monte Dam venture within the Brazilian Amazon in 2015, Indigenous tribes dwelling along the Colossal Bend of the Xingu River began noticing adjustments within the river’s waft. The water they relied on for meals and transportation became disappearing.

Upstream, a new channel would at last divert as powerful as 80% of the water to the hydroelectric dam, bypassing the bend.

The consortium that runs the dam argued that there became no scientific proof that the replace in water waft harmed fish.

However there would possibly perchance be apparent proof of the Belo Monte Dam venture’s affect — from above, write Pritam Das (opens in new tab), Faisal Hossain (opens in new tab), Hörður Helgason (opens in new tab) and Shahzaib Khan (opens in new tab) at the College of Washington. The utilization of satellite tv for computer records from the Landsat program, the crew showed how the dam dramatically altered (opens in new tab) the hydrology of the river.

OpenStreetMap maps of the affected areas after the Belo Monte Project.

Blueprint of the Xingu River’s Colossal bend after the Belo Monte Venture.  (Describe credit: OpenStreetMap contributors)

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“As scientists who work with some distance off sensing, we contain satellite tv for computer observations can empower populations round the field who face threats to their sources,” Das and his colleagues write.

Large reservoir now present after the dam has been built, reducing the flow of water elsewhere.

The first satellite tv for computer image displays the Colossal Bend of the Xingu River on Might perhaps perhaps well perchance additionally merely 26, 2000, forward of the Belo Monte Dam venture began. The image then overlaid on prime is the identical discipline on July 20, 2017.  Gif made with juxtapose.knightlab.com. (Describe credit: NASA)

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It’s hot within the metropolis — and even hotter in some neighborhoods

A lady holds a child up to a fan providing some relief on a hot day.

A avenue fan provides relief on a hot summer day in Contemporary York City. (Describe credit: Stephen Chernin/Getty Pictures)

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Landsat’s devices can additionally measure floor temperatures, allowing scientists to plan heat chance avenue by avenue internal cities as global temperatures upward push.

“Cities are most regularly hotter than surrounding rural areas, but even internal cities, some residential neighborhoods glean dangerously warmer than others appropriate a pair of miles away,” writes Daniel P. Johnson (opens in new tab), who uses satellites to peer the metropolis heat island enact at Indiana College.

Neighborhoods with extra pavement and buildings and fewer trees would possibly perchance perhaps additionally be 10 degrees Fahrenheit (5.5 degrees Celsius) or extra, warmer than leafier neighborhoods, Johnson writes. He realized that basically the most up to this point neighborhoods are usually low-earnings, net majority Black or Hispanic residents and had been subjected to redlining, the discriminatory note once extinct to disclaim loans in racial and ethnic minority communities.

Two maps side by side, on the left represents the density of vegetation and on the right temperatures from warm to hot. Areas with higher density vegetation are visually cooler than areas with sparse vegetation.

Comparing maps of Contemporary York City’s vegetation and temperature displays the cooling enact of parks and neighborhoods with extra trees. (Describe credit: NASA/USGS Landsat)

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“Within these ‘micro-metropolis heat islands,’ communities can experience heat wave prerequisites properly forward of officials mutter a heat emergency,” Johnson writes.

Radiant which neighborhoods face the supreme risks (opens in new tab) enables cities to put collectively cooling facilities and utterly different applications to reduction residents arrange the heat.

The making of ghost forests

Eerie white tree trunks cover the landscape.

The white trunks of a ghost woodland label a coastal North Carolina landscape. (Describe credit: Emily Ury, CC BY-ND)

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Satellites that scan the identical areas 365 days after 365 days would possibly perchance perhaps additionally be indispensable for recognizing adjustments in hard-to-reach regions. They’ll note snow and ice camouflage, and, along U.S. Atlantic flit, loss of life wetland forests.

These eerie landscapes of dreary, time and again bleached-white tree trunks net earned the nickname “ghost forests.”

Emily Ury (opens in new tab), an ecologist now at the College of Waterloo in Ontario, extinct Landsat records to order wetland adjustments. She then zoomed in with excessive-dedication images from Google Earth — which comprises Landsat images — to verify that they were ghost forests.

“The outcomes were excellent. We realized that bigger than 10% of forested wetland (opens in new tab) internal the Alligator River Nationwide Flora and fauna Refuge [in North Carolina] became misplaced in some unspecified time in the future of the last 35 years. Here is federally safe land, without a utterly different human dispute that would be killing off the woodland,” Ury writes.

Aerial view of the Alligator river and surrounding forests.

Landsat’s seek for of the Alligator River and refuge displays signs of ghost forests on the east side of the river. (Describe credit: NASA Earth Observatory)

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Because the planet warms and sea phases upward push, extra salt water is reaching these areas, increasing the amount of salt within the soil of coastal woodlands from Maine to Florida. “Snappy sea stage upward push looks to be to be outpacing the skill of these forests to adapt to wetter, saltier prerequisites,” Ury writes.

Many extra tales would possibly perchance perhaps additionally be realized in Landsat’s images, akin to a chief level notion of the battle’s effects (opens in new tab) on Ukraine’s wheat chop, and how algae blooms net spread in Florida’s Lake Okeechobee (opens in new tab). Limitless projects are the utilization of Landsat records to trace global replace and perhaps earn solutions to complications, from deforestation within the Amazon (opens in new tab) to the fires which net keep Alaska on drag for one more ancient fire season (opens in new tab).

Artist's illustration of Landsat 8 with a large solar panel, above the Earth.

An artist’s rendering of Landsat 8. (Describe credit: NASA/Goddard Fetch 22 situation Flight Center Conceptual Describe Lab)

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This article is republished from The Conversation (opens in new tab) below a Creative Commons license. Read the usual article (opens in new tab).

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Stacy Morford

Stacy Morford became an Associated Press national editor and order govt reporter for over a decade. She additionally covered science, native weather replace and sustainable pattern as an editor at InsideClimate Recordsdata and as a communications officer at Columbia College’s Lamont-Doherty Earth Observatory and at the World Bank. She has a grasp’s stage in training psychology concerned about cognition and studying.