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For all of Landsat’s value to the United States—a 2017 U.S. Geological Survey (USGS) study placed the annual economic benefit of its data to this country at $2.06 billionthe satellite system plays a vital role as a global asset.

Brazilian National Water Agency representatives at USGS EROS Center
Members of the Brazilian National Water Agency (ANA) were at EROS in mid-October 2018 to discuss the mapping of irrigated lands in Brazil, and the measuring and monitoring of water consumption on those lands. From left to right are Thiago Fontenelle (ANA), Mac Friedrichs (SGT Inc.), Daniel Ferreira (ANA), Gabriel Senay (USGS), Jesslyn Brown (USGS), Juliana Lopes (ANA), Matthew Schauer (SGT), William Hughes (USGS), John Dwyer (USGS), and Sergio Ayrimoraes (ANA).

Landsat has long been a part of a U.S. foreign policy strategy that promotes the peaceful use of outer space and the worldwide dissemination of civil space technology for the public good. Today, a network of International Cooperators (IC) acquiring Landsat data for the USGS numbers 14 countries and 20 ground stations.

But beyond just receiving Landsat data from satellites passing overhead, countries are also benefitting from the information that the data provide. Brazil is a good example of that. Two of the biggest applications of Landsat data in that South American country include:

  • The forest loss work done in Brazil by the team of Matt Hansen, a professor in the Department of Geographical Sciences at the University of Maryland, through a project called Global Forest Change.
  • MapBiomas, an initiative involving universities, non-governmental organizations (NGOs), and technology companies, including Google, working together to understand Brazilian territory transformations based on the annual mapping of land cover and land use.

Since 2016, the Agência Nacional de Águas (ANA)—also called the Brazilian National Water Agency—has worked with the USGS and the Earth Resources Observation and Science (EROS) Center to better understand agricultural irrigation across its lands. Nearly 20 percent of all the planet’s rivers flow on Brazilian soil. Brazil uses roughly 72 percent of its available water for its extensive irrigated agricultural needs, including some of the planet’s largest cattle, pig, and poultry operations.

But for all its wealth of water, Brazil also faces significant hydrologic challenges. Drought has baked the country’s semi-arid regions over the past six to seven years, said ANA’s Sérgio Ayrimoraes. Metropolitan regions like São Paulo face significant water supply problems. And it’s not just a lack of rain, either, Ayrimoraes said. The growth in water use and procrastination in meeting water and sanitation needs are testing areas that have already reached their limit in the balance between water supply and water demand.

When ANA officials heard EROS staff presenting about their work on measuring and monitoring water consumption with their Operational Simplified Surface Energy Balance (SSEBop) model at a USGS Water Census conference in Atlanta four to five years ago, the Brazilians’ interest perked right up.

“We are not exactly scientists or researchers,” ANA’s Thiago Fontenelle said. “We are water experts implementing a national water policy. So, USGS support has been very valuable for us.”

EROS Research Physical Scientist Gabriel Senay and his team have developed SSEBop using land surface temperature from Landsat and NASA’s Moderate Resolution Imaging Spectroradiometer (MODIS), as well as weather data, to quantify the amount of water used by land surfaces at field levels up to regional and national scales.

The resulting estimation of evapotranspiration (ET)—evaporation from the Earth’s surface and transpiration through the leaves of plants, which accounts for about 60 percent of the water budget—has become a valuable tool for the Brazilians. Parameterized for Brazilian needs, SSEBop has been applied in that country to compare data from water rights to identify irrigated areas, for planning purposes, and more.

Through workshops and hands-on training, Senay’s team has worked with the Brazilians on everything from the basics of energy balance and ET physics to modeling variables and training them on cloud-computing tools. Senay’s colleague at EROS, Research Physical Scientist Jess Brown, has assisted ANA as well, showing how to map the irrigated agriculture in Brazil. Jess’s work has been a valuable contribution for applying land-classification research using time series data from Landsat, illustrating a strong example of complementary science made possible with accessible cloud tools and team collaboration.

Eyes on Earth Episode 39 - Brazil's Water Use

“I can say it’s a successful partnership,” Fontenelle said. “Remote sensing is valuable in a big and diverse country as Brazil. Once a Landsat remote sensing image is available, we can estimate irrigated areas in the areas we monitor in Brazil. This is amazing for us. It’s a long way from where we were some years ago.”

For EROS, this partnership is mutually beneficial. Mac Friedrichs, a contractor to the USGS who is the lead technical developer with the Google Earth Engine platform on Senay’s project, said Brazil has provided the EROS team an opportunity to see where SSEBop works well and where it doesn’t. A lot of SSEBop’s success is tied to the quality of input datasets in different countries and finding the right sources of information to apply within the model, Friedrichs said.

“The Brazilian team at ANA are very skilled and smart, and they had a lot to share with us as well,” he said. “It’s been very much a learning experience ... we can improve our work, and using improved datasets, we can make better model assumptions and improve the parameters to handle regional differences in various hydroclimatic conditions.”

Friedrichs and the EROS team also like that ANA is sharing its SSEBop knowledge with universities, other government agencies, and local sectors in Brazil. But it’s not just being applied in that South American country. SSEBop is being used in Africa through the Famine Early Warning Systems Network (FEWS NET). Its application has been noted in papers in China, India, and in global water accounting by researchers in the Netherlands.

All of that speaks again to the global impact of Landsat.

“It’s always fun ... through collaboration efforts and building team connections like this one in Brazil ... to have shared goals and ideas for improving the science and seeing the application of this type of work advanced throughout the world,” Friedrichs said.

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