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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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SpaceX to Launch Twin NASA Water Cycle Tracker Satellites

The satellites are scheduled to launch at 3.47 p.m. EDT from Vandenberg Air Force Base in Central California

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SpaceX to Launch Twin NASA Water Cycle Tracker Satellites
SpaceX to Launch Twin NASA Water Cycle Tracker Satellites. Pixabay

On its way to deploy five Iridium Next communications satellites on Tuesday, a SpaceX Falcon 9 rocket will also launch twin NASA satellites that will monitor Earth’s water cycle, marking a unique rideshare arrangement.

The satellites are scheduled to launch at 3.47 p.m. EDT from Vandenberg Air Force Base in Central California. (This corresponds to 1.17 a.m. Wednesday India time), NASA said.

The two Gravity Recovery and Climate Experiment Follow-On mission (GRACE-FO) spacecraft will follow each other in orbit around Earth, separated by about 220 km.

On liftoff, the Falcon 9 first-stage engines will burn for approximately two minutes and 45 seconds before shutting down at main engine cutoff (MECO).

The Falcon 9’s first and second stages will separate seconds later. Then, the second-stage engine will ignite for the first time (SES1) and burn until the vehicle reaches the altitude of the injection orbit, 490 km.

NASA
Representational Image, VOA

While this burn is going on, the payload fairing — the launch vehicle’s nose cone — will separate into two halves like a clamshell and fall away.

When the rocket’s second stage has completed its ascent to the injection orbit altitude, it will pitch down (its nose points down) 30 degrees and roll so that one of the twin GRACE-FO satellites is facing down, toward Earth, and the other is facing up, toward space.

Then the second stage engine will cut off (SECO).

About 10 minutes after liftoff, a separation system on the second stage will deploy the GRACE-FO satellites.

Separation will occur over the Pacific Ocean at about 17.5 degrees North latitude, 122.6 degrees West longitude.

The first opportunity to receive data from the spacecraft will occur at NASA’s tracking station at McMurdo, Antarctica, about 23 minutes after separation, NASA said.

Also Read: A Study by NASA Shows Freshwater Decline in India

After the GRACE-FO satellites are deployed, the Falcon 9 second stage will coast for half an orbit before reigniting its engine (SES2) to take the Iridium Next satellites to a higher orbit for deployment.

GRACE-FO, a collaborative mission of NASA and the German Research Centre for Geosciences (GFZ), continues the work of the original GRACE mission in observing the movement of water and other mass around our planet by tracking the changing pull of gravity very precisely. (IANS)

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