Members Can Post Anonymously On This Site
Drought causes Yangtze to shrink
-
Similar Topics
-
By NASA
Earth (ESD) Earth Explore Explore Earth Home Agriculture Air Quality Climate Change Freshwater Life on Earth Severe Storms Snow and Ice The Global Ocean Science at Work Earth Science at Work Technology and Innovation Powering Business Multimedia Image Collections Videos Data For Researchers About Us 5 Min Read NASA Data, Trainings Help Uruguay Navigate Drought
Uruguay’s Paso Severino Reservoir, the primary water source for Montevideo, on June 13, 2023, captured by Landsat 9. Credits:
NASA Earth Observatory/ Wanmei Liang Lee esta historia en español aquí.
NASA satellite data and trainings helped Uruguay create a drought-response tool that its National Water Authority now uses to monitor reservoirs and guide emergency decisions. A similar approach could be applied in the United States and other countries around the world.
From 2018 to 2023, Uruguay experienced its worst drought in nearly a century. The capital city of Montevideo, home to nearly 2 million people, was especially hard hit. By mid-2023, Paso Severino, the largest reservoir and primary water source for Montevideo, had dropped to just 1.7% of its capacity. As water levels declined, government leaders declared an emergency. They began identifying backup supplies and asked: Was there water left in other upstream reservoirs — mainly used for livestock and irrigation — that could help?
That’s when environmental engineer Tiago Pohren and his colleagues at the National Water Authority (DINAGUA – Ministry of Environment) turned to NASA data and trainings to build an online tool that could help answer that question and improve monitoring of the nation’s reservoirs.
“Satellite data can inform everything from irrigation scheduling in the Great Plains to water quality management in the Chesapeake Bay,” said Erin Urquhart, manager of the water resources program at NASA Headquarters in Washington. “NASA provides the reliable data needed to respond to water crises anywhere in the world.”
Learning to Detect Water from Space
The DINAGUA team learned about NASA resources during a 2022 workshop in Buenos Aires, organized by the Interagency Science and Applications Team (ISAT). Led by NASA, the U.S. Army Corps of Engineers, and the U.S. Department of State, the workshop focused on developing tools to help manage water in the La Plata River Basin, which spans multiple South American countries including Uruguay.
At the workshop, researchers from NASA introduced participants to methods for measuring water resources from space. NASA’s Applied Remote Sensing (ARSET) program also provided a primer on remote sensing principles.
DINAGUA team supervisor Jose Rodolfo Valles León asks a question during a 2022 workshop in Buenos Aires. Other members of the Uruguay delegation — Florencia Hastings, Vanessa Erasun Rodríguez de Líma, Vanessa Ferreira, and Teresa Sastre (current Director of DINAGUA) — sit in the row behind. Organization of American States “NASA doesn’t just deliver data,” said John Bolten, NASA’s lead scientist for ISAT and chief of the Hydrological Sciences Laboratory at NASA’s Goddard Space Flight Center in Greenbelt, Maryland. “We collaborate with our partners and local experts to translate the data into information that is useful, usable, and relevant. That kind of coordination is what makes NASA’s water programs so effective on the ground, at home and around the world.”
The DINAGUA team brought ideas and provided guidelines to Pohren for a tool that applies Landsat and Sentinel satellite imagery to detect changes in Uruguay’s reservoirs. Landsat, a joint NASA-U.S. Geological Survey mission, provides decades of satellite imagery to track changes in land and water. The Sentinel missions, a part of the European Commission managed Copernicus Earth Observation program and operated by ESA (the European Space Agency), provide complementary visible, infrared, and microwave imagery for surface water assessments.
From a young age, Pohren was familiar with water-related challenges, as floods repeatedly inundated his relatives’ homes in his hometown of Montenegro, Brazil. It was extra motivation for him as he scoured ARSET tutorials and taught himself to write computer code. The result was a monitoring tool capable of estimating the surface area of Uruguay’s reservoirs over time.
A screenshot of the reservoir monitoring tool shows the Paso Severino’s surface water coverage alongside time-series data tracking its variations. Tiago Pohren The tool draws on several techniques to differentiate the surface water extent of reservoirs. These techniques include three optical indicators derived from the Landsat 8 and Sentinel-2 satellites:
Normalized Difference Water Index, which highlights water by comparing how much green and near-infrared light is reflected. Water absorbs infrared light, so it stands out clearly from land. Modified Normalized Difference Water Index, which swaps near-infrared with shortwave infrared to improve the contrast and reduce errors when differentiating between water and built-up or vegetated areas. Automated Water Extraction Index, which combines four types of reflected light — green, near-infrared, and two shortwave infrared bands — to help separate water from shadows and other dark features. From Emergency Tool to Everyday Asset
In 2023, the DINAGUA team used Pohren’s tool to examine reservoirs located upstream from Montevideo’s drinking water intake. But the data told a tough story.
“There was water available in other reservoirs, but it was a very small amount compared to the water demand of the Montevideo metropolitan region,” Pohren said. Simulations showed that even if all of the water were released, most of it would not reach the water intake for Montevideo or the Paso Severino reservoir.
Despite this news, the analysis prevented actions that might have wasted important resources for maintaining productive activities in the upper basin, Pohren said. Then, in August 2023, rain began to refill Uruguay’s reservoirs, allowing the country to declare an end to the water crisis.
From right to left: Tiago Pohren, Vanessa Erasun, and Florencia Hastings at the second ISAT workshop in March 2024. Organization of American States Though the immediate water crisis has passed, the tool Pohren created will be useful in the future in Uruguay and around the world. During an ISAT workshop in 2024, he shared his tool with international water resources managers with the hope it could aid their own drought response efforts. And DINAGUA officials still use it to identify and monitor dams, irrigation reservoirs, and other water bodies in Uruguay.
Pohren continues to use NASA training and data to advance reservoir management. He’s currently exploring an ARSET training on how the Surface Water and Ocean Topography (SWOT) mission will further improve the system by allowing DINAGUA to directly measure the height of water in reservoirs. He is also following NASA’s new joint mission with ISRO (the Indian Space Research Organization) called NISAR, which launched on July 30. The NISAR satellite will provide radar data that detects changes in water extent, regardless of cloud cover or time of day. “If a drought happens again,” Pohren said, “with the tools that we have now, we will be much more prepared to understand what the conditions of the basin are and then make predictions.”
Environmental engineer Tiago Pohren conducts a field inspection on the Canelón Grande reservoir, the second-largest reservoir serving Montevideo, during the drought. Tiago Pohren By Melody Pederson, Rachel Jiang
The authors would like to thank Noelia Gonzalez, Perry Oddo, Denise Hill, and Delfina Iervolino for interview support as well as Jerry Weigel for connecting with Tiago about the tool’s development.
Share
Details
Last Updated Sep 10, 2025 Related Terms
Droughts Earth Life on Earth Natural Disasters Water on Earth Explore More
1 min read NASA’s Black Marble: Stories from the Night Sky
Studying the glowing patterns of Earth’s surface helps us understand human activity, respond to disasters,…
Article
1 month ago
4 min read NUBE: New Card Game Helps Learners Identify Cloud Types Through Play
Article
1 month ago
6 min read NASA’s TRACERS Studies Explosive Process in Earth’s Magnetic Shield
Article
2 months ago
Keep Exploring Discover More Topics From NASA
Earth
Your home. Our Mission. And the one planet that NASA studies more than any other.
Explore Earth Science
Earth Science in Action
NASA’s unique vantage point helps us inform solutions to enhance decision-making, improve livelihoods, and protect our planet.
Earth Multimedia & Galleries
View the full article
-
By NASA
On 5/22/24, Chinmay Deval, the Water Security Lead at the SERVIR Science Coordination Office, moderated a virtual panel for the ResilienceLinks monthly webinar series. ResilienceLinks is the knowledge platform for the US Agency for International Development (USAID) Center for Resilience. The theme for May focused on Water Data and Climate Resilience. The panel featured distinguished water experts from the SERVIR global network, including: Jamilatou Chaibou Begou from the Agrometeorology, Hydrology, and Meteorology Regional Center/SERVIR West Africa, Chinaporn Meechaiya from the Asian Disaster Preparedness Center/SERVIR Southeast Asia, Jim Nelson, Principal Investigator of the SERVIR Applied Sciences Team at Brigham Young University, and Angelica Gutierrez from the National Oceanic and Atmospheric Administration (NOAA) Throughout the webinar, panelists shared their expertise and insights on the use of water data to enhance climate resilience. They discussed real-world applications, challenges in data accessibility, and innovative solutions for integrating local knowledge and gender equity into climate adaptation strategies. The webinar was hosted by Peter Epanchin, Senior Climate Adaptation and Resilience Advisor at USAID’s Bureau for Resilience, Environment, and Food Security.
View the full article
-
-
By NASA
4 min read
Preparations for Next Moonwalk Simulations Underway (and Underwater)
It’s not just rising air and water temperatures influencing the decades-long decline of Arctic sea ice. Clouds, aerosols, even the bumps and dips on the ice itself can play a role. To explore how these factors interact and impact sea ice melting, NASA is flying two aircraft equipped with scientific instruments over the Arctic Ocean north of Greenland this summer. The first flights of the field campaign, called ARCSIX (Arctic Radiation Cloud Aerosol Surface Interaction Experiment), successfully began taking measurements on May 28.
Two NASA aircraft are taking coordinated measurements of clouds, aerosols and sea ice in the Arctic this summer as part of the ARCSIX field campaign. In this image from Thursday, May 30, NASA’s P-3 aircraft takes off from Pituffik Space Base in northwest Greenland behind the agency’s Gulfstream III aircraft.Credit: NASA/Dan Chirica “The ARCSIX mission aims to measure the evolution of the sea ice pack over the course of an entire summer,” said Patrick Taylor, deputy science lead with the campaign from NASA’s Langley Research Center in Hampton, Virginia. “There are many different factors that influence the sea ice. We’re measuring them to determine which were most important to melting ice this summer.”
On a completely clear day over smooth sea ice, most sunlight would reflect back into the atmosphere, which is one way that sea ice cools the planet. But when the ice has ridges or darker melt ponds — or is dotted with pollutants — it can change the equation, increasing the amount of ice melt. In the atmosphere, cloudy conditions and drifting aerosols also impact the rate of melt.
“An important goal of ARCSIX is to better understand the surface radiation budget — the energy interacting with the ice and the atmosphere,” said Rachel Tilling, a campaign scientist from NASA’s Goddard Space Flight Center in Greenbelt, Maryland.
About 75 scientists, instrument operators, and flight crew are participating in ARCSIX’s two segments based out of Pituffik Space Base in northwest Greenland. The first three-week deployment, in May and June of this year, is timed to document the start of the ice melt season. The second deployment will occur in July and August to monitor late summer conditions and the start of the freeze-up period.
“Scientists from three key disciplines came together for ARCSIX: sea ice surface researchers, aerosol researchers, and cloud researchers,” Tilling said. “Each of us has been working to understand the radiation budget in our specific area, but we’ve brought all three areas together for this campaign.”
Two aircraft will fly over the Arctic during each deployment. NASA’s P-3 Orion aircraft from the agency’s Wallops Flight Facility in Virginia, will fly below the clouds at times to document the surface properties of the ice and the amount of energy radiating off it. The team will also fly the aircraft through the clouds to sample aerosol particles, cloud optical properties, chemistry, and other atmospheric components.
A Gulfstream III aircraft, managed by NASA Langley, will fly higher in the atmosphere to observe properties of the tops of the clouds, take profiles of the atmosphere above the ice, and add a perspective similar to that of orbiting satellites.
The teams will also compare airborne data with satellite data. Satellite instruments like the Multi-angle Imaging Spectroradiometer and the Moderate Resolution Imaging Spectroradiometer will provide additional information about clouds and aerosol particles, while the Ice, Cloud, and land Elevation Satellite 2 will provide insights into the ice topography below both satellites and aircraft.
The aircraft will fly coordinated routes to take measurements of the atmosphere above ice in three-dimensional space, said Sebastian Schmidt, the mission’s science lead with the University of Colorado Boulder.
“The area off the northern coast of Greenland can be considered the last bastion of multi-year sea ice, as the Arctic transitions to a seasonally ice-free ocean,” Schmidt said. “By observing here, we will gain insight into cloud-aerosol-sea ice-interaction processes of the ‘old’ and ‘new’ Arctic — all while improving satellite-based remote sensing by comparing what we’re seeing with the airborne and satellite instruments.”
By Kate Ramsayer
NASA’s Goddard Space Flight Center, Greenbelt, Md.
Share
Details
Last Updated May 31, 2024 EditorKate D. RamsayerContactKate D. Ramsayerkate.d.ramsayer@nasa.govLocationGoddard Space Flight Center Related Terms
Earth Airborne Science Goddard Space Flight Center Ice & Glaciers Langley Research Center Sea Ice Wallops Flight Facility Explore More
5 min read Antarctic Sea Ice Near Historic Lows; Arctic Ice Continues Decline
Article 2 months ago 5 min read Arctic Sea Ice 6th Lowest on Record; Antarctic Sees Record Low Growth
Arctic sea ice likely reached its annual minimum extent on September 19, 2023, making it…
Article 8 months ago 4 min read NASA Ice Scientists Take Flight from Greenland to Study Melting Arctic Ice
Article 2 years ago View the full article
-
By NASA
4 min read
NASA Data Shows How Drought Changes Wildfire Recovery in the West
California’s 2017 Thomas Fire (shown) was included in a new analysis of more than 1,500 wildland fires teasing out how drought and fire combine to affect western U.S. lands.USDA Forest Service/ Stuart Palley A new study using NASA satellite data reveals how drought affects the recovery of western ecosystems from fire, a result that could provide meaningful information for conservation efforts.
The West has been witnessing a trend of increasing number and intensity of wildland fires. Historically a natural part of the region’s ecology, fires have been exacerbated by climate change—including more frequent and intense droughts—and past efforts to suppress fires, which can lead to the accumulation of combustible material like fallen branches and leaves. But quantifying how fire and drought jointly affect ecosystems has proven difficult.
In the new study, researchers analyzed over 1,500 fires from 2014 to 2020 across the West, and also gathered data on drought conditions dating back to 1984. They found that droughts make it harder for grasslands and shrublands, such as those in Nevada and Utah, to recover after fires—even the less severe blazes. Forests, if not burned too badly, rebound better than grasslands and shrublands because some forest roots can tap into water deeper in the ground. The team reported its findings in the February 2024 issue of Nature Ecology & Environment.
“Many of the West’s grasslands experience low-severity fires,” said Shahryar Ahmed, lead author of the study and a research scientist at NASA’s Goddard Space Flight Center in Greenbelt, Maryland. “This study shows that even those blazes can trigger a slow recovery in these ecosystems if accompanied by a preceding drought.”
If ecosystems don’t have enough time to bounce back before another drought or fire, that could lead to permanent changes in the types of plants growing there. That, in turn, can increase the risk of soil erosion and landslides, and alter the usual patterns of water running off into streams and lakes.
“Once a fire is contained, that’s when the remediation efforts happen,” said Everett Hinkley, the national remote sensing program manager for the U.S. Forest Service, who wasn’t involved in the new research. “Understanding how a particular ecosystem and land cover type is going to respond after the fire informs what actions you need to take to restore the landscape.”
Without such restoration, changes in land cover can cascade to potentially affect agriculture, tourism, and other community livelihoods. To track the recovery of the different ecosystems, the researchers examined changes in evapotranspiration (ET)—the transfer of water to the atmosphere through evaporation from soil and open water and transpiration from plants—before and after the fires. Monitoring evapotranspiration helped the team identify whether different ecosystems, such as forests and grasslands, completely recovered after a fire, or if the recovery was delayed or disrupted.
That evapotranspiration data came from OpenET, a tool that calculates evapotranspiration at the scale of a quarter-acre across the western United States. It does so using models that harness publicly available data from the Landsat program, a partnership between NASA and the U.S. Geological Survey, along with other NASA and NOAA satellites.
“This study highlights the dominant control of drought on altering resilience of vegetation to fires in the West,” said Erin Urquhart, the water resources program manager at NASA Headquarters in Washington. “With ongoing climate change, it is imperative that land managers, policymakers, and communities work together, informed by such research, to adapt to these changes, mitigating risks and ensuring the sustainable use of water and other natural resources.”
The research also showed that forests, grasslands, and shrublands all struggle to recover from droughts that occur close in time with high-severity fires, which are becoming more common in the West. That can lead to potentially lasting changes not only in the plant communities but also in local and regional water dynamics.
Severe fires damage plants to such an extent that evapotranspiration is greatly reduced in the following years, the researchers found. So instead of evaporating into the atmosphere, more water sinks into the ground as recharge or becomes runoff.
Using a subset of nearly 800 fires from 2016 to 2018, the researchers calculated that across all the ecoregions in the study, an average of about 528 billion gallons (two cubic kilometers) of water was diverted as runoff or recharge during the first year after a fire. That’s equivalent to North Dakota’s annual water demand, or one quarter of Shasta Lake, California’s largest humanmade lake.
When more water becomes runoff, it means less could be available for ecosystem recovery or agriculture. As Earth’s climate continues to warm, understanding these shifts is crucial for developing strategies to manage water resources more effectively and ensure water security for future generations.
By: Emily DeMarco, NASA Earth Science Division
Share
Details
Last Updated Mar 27, 2024 EditorEmily DeMarcoContactEmily DeMarcoemily.p.demarco@nasa.gov Related Terms
Earth Natural Disasters Explore More
5 min read Early Adopters of NASA’s PACE Data to Study Air Quality, Ocean Health
Article 2 days ago 4 min read NASA’s Global Precipitation Measurement Mission: 10 years, 10 stories
Article 4 weeks ago 5 min read OpenET Study Helps Water Managers and Farmers Put NASA Data to Work
Article 2 months ago Keep Exploring Discover Related Topics
Missions
Humans in Space
Climate Change
Solar System
View the full article
-
-
Check out these Videos
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.