麻豆淫院

NASA is collaborating with the Alaska Satellite Facility in Fairbanks to create a powerful, web-based tool that will show the movement of land across North America down to less than an inch. The online portal and its underlying dataset unlock a trove of satellite radar measurements that can help anyone identify where and by how much the land beneath their feet may be moving鈥攚hether from earthquakes, volcanoes, landslides, or the extraction of underground natural resources such as groundwater.

Spearheaded by NASA's Observational Products for End-Users from Remote Sensing Analysis () project at the agency's Jet Propulsion Laboratory in Southern California, the effort equips users with information that would otherwise take years of training to produce. The project builds on measurements from spaceborne synthetic aperture radars, or SARs, to generate high-resolution data on how Earth's surface is moving.

For example, water-management bureaus and state geological surveys will be able to directly use the OPERA products without needing to make big investments in data storage, software engineering expertise, and computing muscle.

How it works

To create the displacement product, the OPERA team continuously draws data from the ESA (European Space Agency) Sentinel-1 radar satellites, the first of which launched in 2014. Data from , the NASA-ISRO (Indian Space Research Organization) SAR mission, will be added to the mix after that spacecraft launches later this year.

Satellite-borne radars work by emitting microwave pulses at Earth's surface. The signals scatter when they hit land and water surfaces, buildings, and other objects. Raw data consists of the strength and time delay of the signals that echo back to the sensor.

To understand how land in a given area is moving, OPERA algorithms automate steps in an otherwise painstaking process. Without OPERA, a researcher would first download hundreds or thousands of data files, each representing a pass of the radar over the point of interest, then make sure the data aligned geographically over time and had precise coordinates.

Then they would use a computationally intensive technique called to gauge how much the land moved, if at all, and in which direction鈥攖owards the satellite, which would indicate the land rose, or away from the satellite, which would mean it sank.

"The OPERA project has helped bring that capability to the masses, making it more accessible to state and federal agencies, and also users wondering, 'What's going on around my house?'" said Franz Meyer, chief scientist of the Alaska Satellite Facility, a part of the University of Alaska Fairbanks Geophysical Institute.

Monitoring groundwater

Sinking land is a top priority to the Arizona Department of Water Resources. From the 1950s through the 1980s, it was the main form of ground movement officials saw, as groundwater pumping increased alongside growth in the state's population and agricultural industry. In 1980, the state enacted the Groundwater Management Act, which reduced its reliance on groundwater in highly populated areas and included requirements to monitor its use.

The department began to measure this sinking, called subsidence, with radar data from various satellites in the early 2000s, using a combination of SAR, GPS-based monitoring, and traditional surveying to inform groundwater-management decisions.

Now, the OPERA dataset and portal will help the agency share subsidence information with officials and community members, said Brian Conway, the department's principal hydrogeologist and supervisor of its geophysics unit. They won't replace the SAR analysis he performs, but they will offer points of comparison for his calculations. Because the dataset and portal will cover the entire state, they also could identify areas not yet known to be subsiding.

"It's a great tool to say, "Let's look at those areas more intensely with our own SAR processing,'" Conway said.

The displacement product is part of a series of data products . The project began in 2020 with a multidisciplinary team of scientists at JPL working to address satellite data needs across different federal agencies. Through the , those agencies submitted their requests, and the OPERA team worked to improve access to information to aid a range of efforts such as disaster response, deforestation tracking and wildfire monitoring.