OpenET uses best available science to provide easily accessible satellite-based estimates of evapotranspiration (ET) for improved water management across the western United States. Using the Data Explorer, users can explore ET data at the field scale for millions of individual fields or at the original quarter-acre resolution of the satellite data…
Transformative, Timely ET Data
OpenET employs several well-established methods to generate daily, monthly, and annual satellite-based ET estimates at the field scale. OpenET also provides access to field-scale information on weather and vegetation conditions. Potential applications include:
Support for ET-based irrigation practices that maximize “crop per drop” and reduce costs for fertilizer and water. Support for water trading programs that protect the financial viability of farms during droughts while helping to make water available for other beneficial uses. Development of water budgets and innovative management programs that promote adequate water supplies for agriculture, people, and ecosystems. Support for groundwater management programs that require consistent, accurate ET data for monitoring historical and current consumptive water use…
Reliable Monthly Data at the Field Scale
OpenET provides data at daily, monthly, and annual time steps. ET data are available at the field scale or for other user-defined boundaries with minimal data latencies – making OpenET a powerful tool for real-time water management and decision-making…
Developed with Best Available Science
The project team includes national and international experts in remote sensing of ET, cloud computing, and web development. Our team has worked with leaders from western agriculture, water policy, and water management communities in developing the platform. Our models, data inputs, and accuracy assessments will ultimately be available on an open source basis, making OpenET a transparent resource for ET data developed by leading experts…
An Ensemble of Well-Established Methods
OpenET provides data from multiple satellite-driven models that are used to map ET, and provides a single “ensemble ET” value that is calculated from those models for each location and timestep. OpenET uses Google Earth Engine as a shared platform for data processing and model operation, allowing the science community to work collaboratively and to use consistent, high-quality data inputs to all models. This approach ensures data continuity, helps improve the methods, and creates a well-documented, shared basis for decision-making that truly represents the best available science…
How it Works
OpenET relies entirely on publicly available data as inputs to multiple well-established ET models to calculate ET. The primary inputs include data from Landsat, Sentinel-2, GOES, and other satellites; weather station networks and models; and field boundary and crop type datasets. The satellite data from Landsat are one of the most important inputs to the ET models, which use the satellite data to measure patterns in land surface temperature and vegetation extent and condition at the scale of individual fields. A complete description of the methods used by OpenET can be found here.
From Progressive Farmer:
NASA on Thursday launched an online platform with information on how much water evaporates into the atmosphere from plants, soils and other surfaces in the U.S. West, data it says could help water managers, farmers and state officials better manage resources in the parched region.
The platform, OpenET, uses satellite imagery from the Landsat program, a decades-long project of NASA and the U.S. Geological Survey that records human and natural impacts on Earth’s surface.
Specifically, it provides data for 17 Western states — down to the quarter-acre — on how much evapotranspiration has taken place. That’s the process by which moisture in leaves, soil and other surfaces evaporates into the air.
The West has been mired in drought for more than two decades. Scientists say human-caused climate change has intensified conditions. Water levels at key reservoirs on the Colorado River have fallen to historic lows alongside growing demand, prompting the federal government to declare water cuts for some states next year. A blazing summer and years of record-breaking wildfires have also zapped moisture from the ground.
Detailed information on soil moisture could help farmers and water managers better plan during dry conditions and reduce how much water is used for irrigation, NASA scientists said on a Thursday call with reporters.
“Farmers and water managers have not had consistent, timely data on one of the most important pieces of information for managing water, which is the amount of water that’s consumed by crops and other plants as they grow,” said Robyn Grimm, a water specialist with the Environmental Defense Fund, which helped NASA develop the tool alongside other environmental groups and Google.
“To date, that data has been expensive and fragmented,” she said.
Many large farms in dry areas, such as California’s Central Valley, already have years of experience using advanced data systems to measure evapotranspiration and other water metrics that influence their growing and harvesting seasons and watering schedules.
Cannon Michael runs an 11,000-acre (4,452 hectare) farm in Merced County, California, that produces tomatoes, melons, cotton and alfalfa. Michael said he looked at NASA’s new platform, but didn’t think it would provide any additional benefit for his farm.
“We closely monitor and understand our water use,” he said. “Our farm is 75% drip irrigation, and we have a very detailed scheduling and forecasting process already in place.”
Meanwhile, Colorado rancher Joe Stanko in Steamboat Springs had read about the new tool in a magazine. Her family grows hay for their cattle, and she said the platform could help them determine which fields need more water to replenish soil. It could also help them decide when to harvest hay.
NASA said the platform includes historical data dating back to 1984. In coming months, it will be updated to include information about precipitation rates with the same level of detail. Eventually, the tool will extend to other parts of the U.S., including areas around the Mississippi River and Appalachian region, scientists said.