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Community => Recreation Commons => Our researchers have made a breakthrough! => Topic started by: Buster's Uncle on August 21, 2014, 10:41:02 pm

Title: GPS devices find huge water loss in western US
Post by: Buster's Uncle on August 21, 2014, 10:41:02 pm

High 'n' Dry: GPS Offers New Way to Measure Drought
LiveScience.com
By Tanya Lewis, Staff Writer  3 hours ago


(http://l3.yimg.com/bt/api/res/1.2/bJ2jxv1ZvnphWa5Zt5veNw--/YXBwaWQ9eW5ld3M7Zmk9ZmlsbDtoPTQzMTtweW9mZj0wO3E9NzU7dz01NzU-/http://media.zenfs.com/en_US/News/LiveScience.com/drought-gps.jpg1408644194)
Drought stations around the western U.S., such as this one in the Inyo Mountains near Lone Pine, California, provide a fuller picture of the devastating drought in recent years.



The western United States has suffered a crippling drought for the past three years, but researchers now have a fuller picture of the extent of damage, thanks to a new way to measure how much water has been lost.

Using existing GPS measurements of ground uplift in the western U.S. from 2003 to 2014, researchers found that the land surface has risen approximately 0.15 inches (4 millimeters), and as much as 0.6 inches (15 mm) in California's mountains.

The total water loss across the region is about 240 gigatons, which is equivalent to the amount of mass the Greenland Ice Sheet loses every year, according to the study detailed today (Aug. 21) in the journal Science.

"Water measures are missing an overall picture of how much water is in the system," said study co-author Adrian Borsa, a geophysicist at the Scripps Institution of Oceanography at the University of California, San Diego, in La Jolla.

Hydrologists can measure precipitation and the amount of surface water in streams and reservoirs, but measures of ground water are few and far between, Borsa told Live Science. "What's going on in aquifers is completely unknown."

To remedy the situation, Borsa and his colleagues set out to repurpose existing data from the Plate Boundary Observatory, a network of GPS stations throughout the western U.S. that were built to measure the movement of tectonic plates. The team realized that the same measurements could be used to determine how much water is in the ground, as a gauge of drought.

Water trapped in the ground pushes down on soil, but when water near the surface evaporates, the ground springs upward. "It's the same as if you had a block of rubber and you pushed down on it with your finger," Borsa said. "If you take your finger off, it comes back up." However, the movements of the ground are very subtle, so they are only visible with GPS.

The monitoring stations can measure both vertical and horizontal motion, but the vertical motion is what corresponds to the amount of water locked in the ground. Earthquakes primarily cause horizontal movements, unless they are very large, but the western United States did not experience a major quake during the decade studied, Borsa said. Volcanic activity, such as the Yellowstone hotspot (a volcanic region above a superheated patch of Earth's crust that feeds volcanoes in Oregon, Nevada, Idaho and Wyoming) can also cause vertical motion, so the researchers removed those regions from their data.

The GPS measurements show that the crust in California was actually subsiding in 2011, but started to rise in 2013, coinciding with the recent California drought. Over the 10 years studied, "what we're seeing now is unprecedented," Borsa said.

The data also show that Texas has experienced the same magnitude of drought as California, but over a much smaller area. Upstate New York has suffered a drought as well, while North Dakota and South Dakota have experienced a very wet spell.

The researchers made adjustments for seasonal changes in the uplift due to snow cover in winter and increased soil evaporation in summer. The team also threw out data from parts of California's Central Valley, where farmers are pumping out a large amount of ground water for agriculture. "What's left is a clear signal of what's going on," Borsa said.

In the future, these measurements could be a critical tool for assessing drought, researchers said. "We're hoping one of the local California water agencies picks up on this and sees it as relevant tool, and we would provide these data to them," Borsa said.

GPS measures of drought could be used not only in the U.S., but also around the world, especially in places where other water-monitoring infrastructure doesn't exist, Borsa said.


http://news.yahoo.com/high-n-dry-gps-offers-way-measure-drought-181824668.html (http://news.yahoo.com/high-n-dry-gps-offers-way-measure-drought-181824668.html)

Title: GPS measures western US drought, finds Earth rising
Post by: Buster's Uncle on August 22, 2014, 12:19:24 am

GPS measures western US drought, finds Earth rising
AFP
41 minutes ago


(http://l3.yimg.com/bt/api/res/1.2/ptMW5I.ympgblvMLqV78zA--/YXBwaWQ9eW5ld3M7Zmk9ZmlsbDtoPTYzMztweW9mZj0wO3E9NzU7dz05NjA-/http://media.zenfs.com/en_us/News/afp.com/54febb33e5628cd273b02ef1d13fd7d50348516d.jpg)
As the severe drought in the western US continues, a field goes unplanted in Firebaugh, California on August 21, 2014 (AFP Photo/Justin Sullivan)



Washington (AFP) - Scientists using GPS technology to study the extent of the western US drought said Thursday the water shortage is causing parts of the Earth's crust to rise.

Some 62 trillion gallons -- equivalent to a six-inch (15-centimeter) layer of water -- have been lost since 2013, causing a slight upward lift across the region, according to the study in the journal Science.

The "uplift" effect equals some 15 millimeters (more than half an inch) in California's mountains and around four millimeters (0.16 of an inch) across the west.

The study was conducted by scientists at Scripps Institution of Oceanography at the University of California, San Diego.

Researchers found that precise GPS stations within the National Science Foundation's Plate Boundary Observatory and beyond had moved upward in recent years, coinciding with the current drought.

The study said the rise is not likely to increase the risk of earthquakes since it has "virtually no effect on the San Andreas fault."

Scripps researcher Dan Cayan said the technique could be used to measure changes in fresh water stocks across the globe.

"This technique can be used to study changes in fresh water stocks in other regions around the world, if they have a network of GPS sensors," said Cayan.

A NASA study out last month found the drought posed a major threat to underground water resources and the regional water supply.

Since 2000, seven western states -- including Arizona, California, Colorado, Nevada, New Mexico, Utah and Wyoming -- have seen the driest 14-year period in a century.


http://news.yahoo.com/gps-measures-western-us-drought-finds-earth-rising-223220278.html (http://news.yahoo.com/gps-measures-western-us-drought-finds-earth-rising-223220278.html)

Title: Drought is slightly elevating ground in U.S. West, study finds
Post by: Buster's Uncle on August 22, 2014, 01:38:50 am

Drought is slightly elevating ground in U.S. West, study finds
Reuters
By Alex Dobuzinskis  1 hour ago



LOS ANGELES (Reuters) - A drought has robbed the U.S. West of 63 trillion gallons (238 trillion liters) of water, and with all that weight off the land the ground in the region has risen by several millimeters, according to a study released on Thursday.

The findings by scientists at Scripps Institution of Oceanography at the University of California, San Diego, were published in the online edition of the journal Science.

The researchers relied on data from global positioning system (GPS) stations throughout the West, measuring how much GPS sensors showed the land had risen beneath them.

The uplift is the largest in the U.S. West since researchers began using GPS data 10 years ago. The researchers did not find the uplift has any effect on the likelihood of earthquakes.

The research underscores the severity of the drought in the West, which in California is expected to cost the state economy $2.2 billion in lost crops, jobs and other damages.

The 63 trillion gallons of water missing in the U.S. West is the equivalent of a 4-inch (10-cm) layer of water spread across the entire region, researchers found.

On average, the loss of water resulted in an average uplift of the land in the West of 4 millimeters (0.15 inch), with up to 15 millimeters (0.6 inch) of uplift seen in California's mountains, according to Scripps.

"The amount of uplift that occurs from 2013 onward both in the magnitude and extent was unlike anything in the GPS record that we had," said Scripps researcher Adrian Borsa. "We were tremendously surprised that nobody had found it before, we considered ourselves very lucky."

The water that has left the West has not simply disappeared, it has just been redistributed to other parts of the globe, he said.

The GPS systems used for the study were originally deployed for the study of plate tectonics.

But this novel use of the data, especially due to its value in estimating changes in underground aquifers and in snowcaps, could help officials in charge of water management plan for how to distribute the valuable natural resource, researchers said.

(Reporting by Alex Dobuzinskis; Editing by Daniel Wallis and Eric Beech)


http://news.yahoo.com/drought-slightly-elevating-ground-u-west-study-finds-225035310.html (http://news.yahoo.com/drought-slightly-elevating-ground-u-west-study-finds-225035310.html)

Title: GPS devices find huge water loss in western US
Post by: Buster's Uncle on August 22, 2014, 04:52:34 am

GPS devices find huge water loss in western US
Associated Press
1 hour ago



SAN DIEGO (AP) — About 63 trillion gallons of water have been lost to drought in the western United States, enough to blanket the region with 4 inches of water, according to a study published Thursday.

Researchers at the Scripps Institution of Oceanography at the University of California, San Diego, arrived at the conclusion by measuring the level of the earth's crust with a network of GPS stations that is normally used to predict earthquakes.

When water is lost because of a lack of rain and snow, the earth's crust rises. The sensors show that the earth's crust has risen an average of 4 millimeters in the western United States since last year and as much as 15 millimeters in the California mountains.

The earth's crust typically sags in the winter and spring, weighed down by water, and it rises during the dry season in summer and fall, said co-author Adrian Borsa. The authors removed those seasonal factors when analyzing about a decade of data from GPS stations within the National Science Foundation's Plate Boundary Observatory.

Last year, an area stretching west of the Rocky Mountains witnessed a "massive uplift," Borsa said. The rise was most striking in the Sierra Nevada mountains and California coastal regions, but it was spread over the entire region, unlike previous years when some pockets have gone up and others went down.

"It's just amazing to us that this covers the entire western United States," Borsa said.

The loss of water since last year is equivalent to the annual loss from the Greenland Ice Sheet, according to the study published in the journal Science.

The findings do not appear to raise any serious concerns about earthquake hazards, said Borsa, who hopes authorities use the measurements as a tool to measure the impact of drought. The findings cannot be compared to the severity of earlier droughts because the measurements were not used then.


http://news.yahoo.com/gps-devices-huge-water-loss-western-us-004206945.html (http://news.yahoo.com/gps-devices-huge-water-loss-western-us-004206945.html)