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Earth Day Connections: NASA Investigates Vegetation

vegetation change

From the vantage point of space, NASA’s fleet of Earth-observing satellites joins with those of partner interagency and international agencies to investigate and illuminate connections between ecosystems that are continents apart, or right next door. With a global perspective, scientists can observe how factors like deforestation, climate change and disasters impact forests and other plant life – while also studying how changes in vegetation impact air quality, waterways and the climate. Vegetation is the primary energy source for nearly all life on Earth, so monitoring it and forecasting how it could be impacted by climate change is key.

In the Amazon, NASA Earth scientists monitor forests and bring these data into the hands of local decision-makers. NASA data provides information about the clearing of trees for agriculture and ranching as well as the impacts of drought on tree mortality. People cut down forests and then ignite the piles of trees and other vegetation, leading to wildfires, which can be detected by instruments including the thermal imager on the Suomi NPP satellite. In 2020, these sensors detected where 1.4 million fires took place. The fires generate smoke that can drift over the continent and be seen from space.

With instruments that collect images of Earth’s surface, researchers can also track the scale of those fires and forest clearings over the years, and even over decades. With the joint NASA/U.S. Geological Survey’s Landsat mission, which launched its first satellite in 1972 and is scheduled to launch Landsat 9 in September 2021, scientists can track changing patterns of deforestation that tells them how Amazonian agricultural practices have changed, from small family holdings to massive ranching operations.

Tracking Plant Health from Space

Satellites can detect how “green” an area is – showing the health of plants that are growing in a particular site. While fires, deforestation and drought lead to the tropical Amazon being less green, warming temperatures in the Arctic lead to tundra and boreal regions becoming greener. Using 87,000 Landsat images spanning nearly three decades, scientists found that a third of the land cover of Canada and Alaska looked different in 2012 as compared to 1985. With warmer temperatures, and longer growing seasons, shrubs become denser on grassy tundras, transforming what they looked like from space.

Since plants take up carbon dioxide from the air as they undergo photosynthesis to make food, it may seem that having a greener Arctic would a result in less of the greenhouse gas in the atmosphere. However, a recent study using satellite data and computer models found that any increased carbon uptake in the Arctic is offset by a decline in the tropics. There, warmer global temperatures have led to a drier atmosphere. That means less rainfall and more drought in places like the Amazon, which leads to a drop in tree growth and increases in tree mortality – and less carbon taken from the atmosphere. Soon, water availability could limit the amount of greening in the Arctic as well, the scientists found. As forests expand or are cut back, researchers use data from instruments including MODIS and satellites like Landsat to measure their extent and health.

A new suite of NASA instruments in space also measure the health of forests. The Global Ecosystem Dynamics Investigation – or GEDI – instrument aboard the International Space Station uses lasers to measure the height of trees, allowing researchers to investigate how ecosystems are changing and how the carbon and water cycles are shifting in a warming climate. The Ice, Cloud and land Elevation Satellite 2, or ICESat-2, uses a similar technique to measure heights, and can reach higher latitudes to see changes in the Arctic biomes as well. And the Ecosystem Spaceborne Thermal Radiometer Experiment on Space Station, or ECOSTRESS, measures the temperature of plants, to help determine their water consumption and health.

From Forests to Farms

While climate change impacts the growth and health of vegetation, naturally occurring weather patterns have an impact as well. Scientists with NASA Harvest are looking into the connections between El Niño/La Niña weather patterns, and the farming conditions and crop yields in eastern and southern Africa. During El Niño years, winds and currents in the equatorial Pacific Ocean cause water to pile up against South America, impacting weather patterns around the globe – even in Africa. Researchers found that southern Africa tends to have decreased crop yields during El Niño phases, while eastern Africa sees increased crop yields in those years – knowing these relationships can help farmers and policy makers prepare for a given season.

NASA satellites and science also help farmers in the United States monitor and track their crops. Having more information about rainfall, plant health and other data gives farmers information they use to deal with the extreme weather events that are increasing due to climate change, as well as shifting planting zones and other effects like early freezes and heavier spring rains. The U.S. Department of Agriculture estimates and tracks crop production using farmer surveys and ground observations, with a big-picture assist from Landsat data, NASA computer models and other Earth science resources. They also use MODIS instruments to monitor daily vegetation health – all to help determine what the crop yield will be, and which areas could be facing problems.

These same satellites can also help scientists track the unwanted products of some agricultural fields, including runoff that flows into waterways. Farms, forests, tundra – all these vegetated ecosystems connect to other spheres of our home planet.

By Kate Ramsayer
NASA’s Goddard Space Flight Center, Greenbelt, Md.

Reposted from original article

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ACTIVATE Begins Year Two of Marine Cloud Study

NASA's ACTIVATE mission recently began its second year of flights. Here, final preparations are being made to the HU-25 Falcon prior to a flight.

A NASA airborne study has returned to the field for a second year of science flights to advance the accuracy of short- and long-term climate models.

The Aerosol Cloud meTeorology Interactions oVer the western ATlantic Experiment (ACTIVATE) began the third of six planned flight campaigns — two campaigns each year beginning in 2020 and ending in 2022 — in late January at NASA’s Langley Research Center in Hampton, Virginia.

Cloud formation in the atmosphere depends on the presence of tiny particles called aerosols. ACTIVATE scientists are working to understand how variations in these particles from human and natural sources affect low lying clouds over the ocean and how those clouds in turn affect the removal of these particles from the atmosphere.

Cloud feedback, or the absorption and reflection of solar energy by clouds, is one of the biggest remaining uncertainties in climate models. By unraveling some of the mysteries of the formation and evolution of clouds, ACTIVATE scientists will provide crucial data to reduce those uncertainties.

Researcher Luke Ziemba checks an instrument on the Falcon prior to a flight.

Luke Ziemba checks an instrument
Researcher Luke Ziemba checks an instrument on the Falcon prior to a flight.
Credits: NASA/David C. Bowman

The western North Atlantic Ocean is an ideal location for the study because it provides a wide range of weather conditions and receives a variety of aerosol types from sources such as the East Coast, the ocean and even wildfires from the West Coast — as researchers learned during the 2020 flights.

Cloud droplets can form on those aerosols and the first year of flight data revealed the broad range of cloud droplet number concentrations in this region of the Atlantic. These concentrations — not especially well represented in existing datasets — are a fundamental driver of the clouds themselves, and are thus key to understanding the multiple cloud types with varying properties based in the boundary layer area near the ocean’s surface. Data from the 2020 flights indicate that the outflow of North American pollution is a major source of aerosols activating into droplets, with a trend toward lower particle and drop concentrations with distance from the shore.

Also noteworthy from the 2020 flights was sampling in cold-air-outbreak conditions, where instrument data are currently being used to validate and improve models trying to better simulate development of associated clouds. Scientists believe the dry air causes aerosols near the ocean surface to change shape, which alters how they scatter light. The frequency and magnitude of these events was unexpected and affects how researchers use satellite measurements to retrieve information about the amount, type and properties of these aerosols.

HU-25 Falcon and King Air

HU-25 Falcon and King Air
The HU-25 Falcon and King Air on the tarmac prior to a flight. The aircraft fly in coordinated fashion — the Falcon flying through clouds taking measurements from the surrounding atmosphere, and the King Air flying at higher altitude taking both complementary remote sensing measurements from above and launching dropsondes to get important weather data.
Credits: NASA/David C. Bowman

To collect this data, the study employs two aircraft flying in coordinated fashion — an HU-25 Falcon flying through clouds taking measurements from the surrounding atmosphere and a King Air flying at higher altitude taking both complementary remote sensing measurements from above and launching dropsondes to get important weather data.

COVID-19 forced the ACTIVATE team to alter its 2020 flight schedule and push the second set of flights originally planned for the spring to late summer. With continued stringent safety protocols, ACTIVATE researchers hope to stick to their planned schedule in 2021, with the current flights lasting through March and a second set of flights in May and June.

“Our team did a remarkable job of persevering and staying focused under very challenging circumstances last year, and we aim to continue that momentum and focus into this next deployment,” said Armin Sorooshian, ACTIVATE principal investigator and atmospheric scientist at the University of Arizona. “If the 2021 flight data are anywhere near as intriguing in terms of the range of aerosol and meteorological conditions we observed in 2020, they’ll be extremely rich and build on an already large and valuable data archive for the international research community. Building statistics across a range of atmospheric variability is critical for better understanding of aerosol-cloud-meteorology interactions.”

ACTIVATE is one of five NASA Earth Venture Suborbital campaigns originally scheduled to take to the field in 2020. Three of the five were postponed in 2020 due to logistical and safety challenges posed by COVID-19. To learn more about the other campaigns, visit:

Joe Atkinson
NASA Langley Research Center


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How NASA is Helping the World Breathe More Easily

Look around. Can you see the air? No?

Luckily, many of NASA’s Earth-observing satellites can see what the human eye can’t — including potentially harmful pollutants lingering in the air we breathe. From the vantage point of space, these satellites help us measure and track air pollution as it moves around the globe and have contributed significantly to our decades-long quest for cleaner air.

When we talk about “air pollution,” we’re referring to chemicals or particles in the atmosphere that are known to have negative health effects on humans. The Clean Air Act of 1970 established legislation that requires the tracking of six of those pollutants — nitrogen dioxide (NO2), ground-level ozone, carbon monoxide, particulate matter (microscopic specks of solid or liquid material in the air), sulfur dioxide, and lead. Satellite instruments are measuring all of these except lead.

NASA has been involved in the study of air quality for decades from space and with ground sensors, creating a time series of global data records critical to understanding the impacts and causes of air pollution and to helping design solutions. This article highlights a few of the many projects under way now and planned for the years to come.

Air pollution can appear as a gray or orange haze enveloping a city. What the naked eye can’t see are the hundreds of chemical reactions taking place to produce that pollution. NASA science can reveal a more complete picture of atmospheric chemistry.
Credits: NASA’s Goddard Space Flight Center/Scientific Visualization Studio
Download This Video in HD from NASA Goddard’s Scientific Visualization Studio


Measured in Space, Used on Earth

In analyzing spaceborne data, one thing is abundantly clear — reducing emissions from human activities can have a profound effect on air quality.

China’s recent large-scale response to the COVID-19 pandemic, which included quarantines and limitations on industrial activities and travel, is a particularly vivid example of this. Data from instruments on NASA’s Aura and the European Space Agency’s Sentinel-5 satellites showed a significant decrease in nitrogen dioxide (NO2) — a noxious gas emitted by power plants, industrial facilities and motor vehicles — over much of the country during that time.

The pandemic presents a unique use-case for spaceborne Earth observations; however, satellite-derived air quality data have applications across a wide array of disciplines. That’s where NASA’s Health and Air Quality applications program demonstrates its value. The program builds invaluable partnerships with other agencies, industry and nonprofits to facilitate the use of this data in solving real world problems.

“We funded a project led by the Environmental Protection Agency (EPA) to assimilate NASA Earth observations into their “AirNow” system,” said program manager John Haynes.

The AirNow system is the EPA’s platform for distributing national, real-time air quality reports and forecasts. The measurements primarily come from thousands of monitoring stations on the ground across the United States, Mexico, and Canada; however, those ground monitoring stations are not all-encompassing.

“The ground monitors cover a good part of the U.S., especially around metropolitan areas. But there are large sections of the country that don’t have monitoring stations,” said Haynes. “By introducing satellite aerosol optical depth observations from the MODIS instrument, we can measure those areas too, which allows us to form a more accurate image of how air pollution — and specifically fine particulate matter — is distributed across the country and how it changes over time.”

By incorporating data from the Ozone Monitoring Instrument (OMI), a Dutch-Finnish contribution to NASA’s Aura satellite mission, the EPA and NASA were also able to identify a significant drop in NO2 over the last 15 years in the United States — evidence that regulations put into place by the Clean Air Act 50 years ago — vehicle gas mileage regulations, a shift to cleaner fuels, and so on — are, indeed, working.

“We’ve been able to show that since 2004, NO2 levels have dropped as much as 50% depending on what metropolitan area we’re talking about. In fact, the air in the United States is now the cleanest it has been in the modern industrial era,” Haynes said.

While ozone in the stratosphere is critical to maintaining life on Earth, surface ozone, shown here, is a toxic gas to most plant and animal species. NASA merges satellite data with models to provide a snapshot of chemistry throughout the atmosphere at any given time and help predict air quality worldwide. Credits: NASA's Goddard Space Flight Center/Scientific Visualization Studio

While ozone in the stratosphere is critical to maintaining life on Earth, surface ozone, shown here, is a toxic gas to most plant and animal species. NASA merges satellite data with models to provide a snapshot of chemistry throughout the atmosphere at any given time and help predict air quality worldwide.
Credits: NASA’s Goddard Space Flight Center/Scientific Visualization Studio

Connecting the (data) dots

With the abundance of data coming in — there are dozens of Earth-observing satellites currently on orbit — one of the biggest challenges is connecting stakeholders with the right “tools” or datasets for what they’re trying to accomplish, and in some cases, teaching them how incorporate this type of data into their planning.

“To address this issue, our team has developed a website where we help users navigate all of these resources, from someone who has never really used satellite data before to more advanced stakeholders looking to make better decisions and inform the public on issues of air quality,” says Tracey Holloway, leader of the NASA-funded Health and Air Quality Applied Sciences Team (HAQAST), a group of air quality and public health scientists from government offices and universities across the country.

Wildfires in California, for example, have caused air quality concerns in recent years. A HAQAST tiger team was able to look at emissions and develop new methods for using existing data from the VIIRS and MODIS instruments to support the state of California in its understanding and quantification of emissions. HAQAST also helped to get data from newer satellites like GOES-16 into the state’s hands.

According to the Global Burden of Disease report, air pollution is the leading environmental cause of mortality — a statistic of which many in the public health sector are well aware. And the availability of satellite observations is changing the dialogue around it.

“Just within the health community, we have observed the growing trend of research collaborations that bridge expertise across environmental health disciplines. As we continue to train the global health workforce, we must identify the skillsets that can prepare the workforce to manage the emerging risks of the future. For example, one skillset is the knowledge and use of innovative data sources – including satellite data – whether they apply data for research purposes or interpret findings for educational outreach activities,” said Helena Chapman, associate program manager of NASA Health and Air Quality applications.

Holloway adds, “The abundance of satellite data right now is amazing. Just in the past 10 years, it’s been remarkable how many agencies, nonprofits, cities and states have gone from not even knowing satellites could detect air pollution to actively using the data in their day-to-day operations.”

Looking Ahead

Right now, our satellites can measure a number of chemicals in the air over the United States and globally on a daily basis. But several missions scheduled to launch in the next few years will be able to do even better.

For example, the Tropospheric Emissions: Monitoring Pollution (TEMPO) mission is designed to measure several different pollutants — including NO2 and ozone — over the United States during every daylight hour. TEMPO will give scientists the ability to see how pollution sources and concentrations change throughout the course of a day. Part of an international constellation of like satellites that includes South Korea’s Geostationary Environment Monitoring Spectrometer (GEMS), and the European Space Agency’s Sentinel-4, TEMPO is scheduled to launch in 2022.

The Multi-Angle Imager for Aerosols (MAIA) mission, also scheduled to launch in the early 2020s, will improve our understanding of particulate matter — those tiny, microscopic particles lingering in the air — with particular focus on large metropolitan areas. Data like this will help the health community better understand the connection between aerosol pollutants and health problems including adverse birth outcomes and cardiovascular diseases.

“MAIA will allow us to study these aerosols in detail, tell us how big they are and how many of them are in that very small category that is most harmful to human health,” said Barry Lefer, program scientist of NASA’s Tropospheric Composition program. “We’ll also be able to better understand what the particles are made of which will lead us to where they came from (like auto exhaust for example).”

Even further in the future, the possibilities are many.

“I’d love to see a future where real-time Earth observation data is seamlessly and continuously available to everyone — from orbit to the palm of your hand,” said Haynes. “It would allow anyone to make fast decisions regarding air quality and their health.”

By Esprit Smith

NASA’s Earth Science News Team

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Drought-Stressed Forest Fueled Amazon Fires

NASA's ECOSTRESS sensor measured the stress levels of plants when it passed over the Peruvian Amazon rainforest on Aug. 7, 2019. The map reveals that the fires were concentrated in areas of water-stressed plants (brown). The pattern points to how plant health can impact the spread of fires. Credits: NASA/JPL-Caltech/Earth Observatory

NASA’s ECOSTRESS sensor measured the stress levels of plants when it passed over the Peruvian Amazon rainforest on Aug. 7, 2019. The map reveals that the fires were concentrated in areas of water-stressed plants (brown). The pattern points to how plant health can impact the spread of fires.
Credits: NASA/JPL-Caltech/Earth Observatory

A new satellite-based map of a section of the Amazon Basin reveals that at least some of the massive fires burning there this past summer were concentrated in water-stressed areas of the rainforest. The stressed plants released measurably less water vapor into the air than unstressed plants; in other words, they were struggling to stay cool and conserve water, leaving them more vulnerable to the fires.

The fires in the Amazon Basin, which continue to burn into November, are mainly the result of such human activities as land clearing and deforestation. The pattern — spotted from space by NASA’s ECOsystem Spaceborne Thermal Radiometer Experiment on Space Station (ECOSTRESS) — points to how water-stressed plants can impact the spread of fires. The data may one day help NASA’s Earth-observing missions predict the path of future forest or brush fires like those currently raging in California.

The primary mission of ECOSTRESS, an instrument that measures thermal infrared energy emitted from the land surface, is to provide insight into plants’ health by taking their temperature. To keep cool, plants “sweat” by releasing water vapor through their pores, a process called evapotranspiration. After multiple orbits, ECOSTRESS is able to measure how much plants transpire and track their response to climate change.

In August, fires spread over large swaths of the Amazon Basin. ECOSTRESS captured the first image of the Amazon rainforest in Peru before the fires began, on Aug. 7. It shows a surface temperature map revealing water-stressed and non-stressed forest (shown in brown and blue, respectively). The fire icons represent fires imaged by NASA’s Terra satellite between Aug. 19 and 26. The fires are limited primarily to areas of water-stressed plants that transpired the least. The second image, taken by the Terra satellite on Aug. 18, shows the ECOSTRESS study area and smoke from active fires in the rainforest.

This satellite image, taken by NASA's Earth-observing Terra satellite on Aug. 18, 2019, shows the ECOSTRESS study area in the Amazon Basin and smoke from active fires in the rainforest. Credits: NASA/JPL-Caltech/Earth Observatory

This satellite image, taken by NASA’s Earth-observing Terra satellite on Aug. 18, 2019, shows the ECOSTRESS study area in the Amazon Basin and smoke from active fires in the rainforest.
Credits: NASA/JPL-Caltech/Earth Observatory

The image also reveals how certain parts of the forest were more resilient, seeming to protect themselves from burning. Plants in these areas were cooler — in other words, they released more water vapor from their leaves — than plants in the burn zones, though mission scientists don’t know whether that’s a coincidence or a direct causal relationship. The water-stressed areas of the forest look as green and healthy as these cooler areas, making them invisible except to a radiometer that can measure thermal infrared energy from the surface.

“To the naked eye, the fires appear randomly distributed throughout the forest,” said Josh Fisher, ECOSTRESS science lead at NASA’s Jet Propulsion Laboratory in Pasadena, California. “But, if you overlay the ECOSTRESS data, you can see that the fires are mainly confined within the highly water-stressed areas. The fires avoided the low-stress areas where the forest appears to have access to more water.”

It’s still a mystery why some plants become stressed while other plants don’t, though scientists believe it’s dependent on factors like the species of plant or amount of water in the soil. The data from ECOSTRESS will help answer questions about which plants will thrive in their changing environments and could also be used to help with decisions related to water management and agricultural irrigation.

JPL built and manages the ECOSTRESS mission for the Earth Science Division in the Science Mission Directorate at NASA Headquarters in Washington. ECOSTRESS is an Earth Venture Instrument mission; this program is managed by NASA’s Earth System Science Pathfinder program at NASA’s Langley Research Center in Hampton, Virginia.

More information about ECOSTRESS is available here:

Arielle Samuelson
Jet Propulsion Laboratory, Pasadena, Calif.


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