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Groundwater depletion in India worst in world: NASA

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Washington: Groundwater is disappearing fast from the world and India is among the worst hit, shows data from NASA’s Gravity Recovery and Climate Experiment (GRACE) satellites.3686365971_12107421e7_o

Among the world’s largest groundwater basins, the Indus Basin aquifer of India and Pakistan, which is a source of fresh water for millions of people, is the second-most overstressed with no natural replenishment to offset usage, said two new studies led by the University of California – Irvine (UCI), using data from GRACE satellites.

About a third of the Earth’s largest groundwater basins are being rapidly depleted by human consumption, the studies said.

Groundwater aquifers are typically located in soils or deeper rock layers beneath the Earth’s surface.

The most overburdened aquifers are in the world’s driest areas, where populations draw heavily on underground water. Climate change and population growth are expected to intensify the problem, the researchers warned.

“What happens when a highly stressed aquifer is located in a region with socioeconomic or political tensions that can’t supplement declining water supplies fast enough?” asked Alexandra Richey, the lead author on both studies, who conducted the research as a UCI doctoral student.

“We are trying to raise red flags now to pinpoint where active management today could protect future lives and livelihoods,” Richey said.

The Arabian Aquifer System, an important water source for more than 60 million people, is the most overstressed in the world, the findings showed.

The studies are the first to comprehensively characterise global groundwater losses with data from space, using readings generated by NASA’s twin GRACE satellites.

GRACE measures dips and bumps in the Earth’s gravity, which are affected by the mass of water.

In the first paper, researchers found that 13 of the planet’s 37 largest aquifers studied between 2003 and 2013 were being depleted while receiving little to no recharge.

Eight were classified as “overstressed”, with nearly no natural replenishment to offset usage.

Another five were found to be “extremely” or “highly” stressed, depending upon the level of replenishment in each.

Those aquifers were still being depleted but had some water flowing back into them.

“Given how quickly we are consuming the world’s groundwater reserves, we need a coordinated global effort to determine how much is left,” principal investigator Jay Famiglietti, who is also the senior water scientist at NASA’s Jet Propulsion Laboratory in Pasadena, California, said.

The findings appeared in the journal Water Resources Research. (IANS)

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Hubble Returns To Normal Functioning Soon: NASA

After the engineering tests have been completed, Hubble is expected to soon return to normal science operations, NASA stated

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Hubble's backup gyro, which had been off for more than 7.5 years, was incorrectly returning extremely high rotation rates. Flcikr

NASA has brought Hubble Space Telescope’s seven-year old backup gyroscope (gyro) back to life, after the spacecraft entered safe mode due to a failed gyro earlier this month, the US space agency said on Tuesday.

A gyro is a device that measures the speed at which the spacecraft is turning and is needed to help Hubble turn and lock on to new targets.

Hubble’s backup gyro, which had been off for more than 7.5 years, was incorrectly returning extremely high rotation rates, NASA said in a statement.

Hubble
The Hubble Telescope hovering in space. Wikimedia Commons

This gyro was turned on after the spacecraft entered safe mode due to a failed gyro on October 5.

Additional tests will be performed to ensure Hubble can return to science operations with this gyro, NASA said.

To correct high rotation rates, the Hubble team executed a running restart of the gyro on October 16.

This procedure turned the gyro off for one second, and then restarted it before the wheel spun down.

However, the data showed no improvement in the gyro’s performance.

Hubble Telescope. red dwarf
This gyro was turned on after the spacecraft entered safe mode due to a failed gyro on October 5. Flickr

The team, then on October 18, commanded a series of spacecraft maneuvers, or turns, in opposite directions to attempt to clear any blockage that may have caused the float to be off-centre and produce the exceedingly high rates.

During each maneuver, the gyro was switched from high mode to low mode to dislodge any blockage that may have accumulated around the float.

They noticed a significant reduction in the high rates, allowing rates to be measured in low mode for brief periods of time.

On October 19, the team again commanded Hubble to perform additional maneuvers and gyro mode switches, which appear to have cleared the issue.

NASA mars, UAE, Hubble
The planet Mars is shown May 12, 2016 in this NASA Hubble Space Telescope view when it was 50 million miles from Earth. VOA

The rotation rates produced by the backup gyro have since reduced and are now within an expected range, NASA noted.

Also Read: New Gamma-Ray Collection Named After Hulk, Godzilla: NASA

The team plans to execute a series of tests to evaluate the performance of the gyro under conditions similar to those encountered during routine science observations, including moving to targets, locking on to a target, and performing precision pointing.

After these engineering tests have been completed, Hubble is expected to soon return to normal science operations, NASA stated. (IANS)