Posted on February 24, 2012 by geography lady
The Aral Sea, Before the Streams Ran Dry : Image of the Day.
This image, from 1964, shows the Aral Sea as it existed for millenia. In the middle of the vast arid region of Central Asia, the Aral Sea was an oasis of wetlands, water, and islands fed by snowmelt in faraway mountains.
Beginning in the 1950s and 60s, the former Soviet Union begin to divert the rivers that feed the sea for agricultural purposes.
The dams, canals, and other water works were built in order to transform the desert into agricultural fields for cotton and other crops. The Aral Sea has been slowly disappearing ever since.
As the crops flourished, the sea began to shrink. The large cities surrounding the sea, which were home to large fishing industries, were left stranded several miles from the shore and eventually were abandoned.
The increasingly salty water became polluted with fertilizer and pesticides. Blowing, salty dust from the exposed lakebed became a public health hazard and degraded the soil. Croplands had to be flushed with larger and larger volumes of river water. The loss of the moderating influence of the Aral Sea made winters colder and summers hotter and drier.
Now just 10% of its original size, the sea is virtually gone. What will the future hold? If the surrounding countries allow the rivers to run free again, will the sea recover? Will it be too polluted to support life? How will the agricultural communities that depend on the river water survive as their land grows too salty to support crops?
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Posted on January 21, 2012 by geography lady
via Drought Causes Mexico Food Shortages : Image of the Day.
The growing season of 2011 was not kind to the southern United States and northern Mexico. As racing fires, heat, and record-dry conditions in Texas claimed attention, crops were quietly failing across the border in northern Mexico.
The current La Nina, which is strengthening again, is probably to blame for the prolonged drought. Mexico has begun food deliveries to Tarahumara communities in the northern region of Mexico, which have hit hard by food shortages due to the drought.
The peaking La Nina will bring rain and storms to parts of North America, but here in Texas we have more drought to look forward to.
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Posted on October 18, 2011 by geography lady
Grand New View of the Canyon : Image of the Day
On October 17, 2011, NASA and Japan’s Ministry of Economy, Trade and Industry (METI) released a significantly improved version of a digital topographic map of Earth based on data from ASTER. Known as a global digital elevation model, the map was created from stereo-pair images; that is, sets of two slightly offset two-dimensional images were merged to create the three-dimensional effect of depth.
The maps drape an aerial photo over a digital elevation model, creating a three-dimensional view.
“These data can be used for a broad range of applications, from planning highways and protecting lands with cultural or environmental significance, to searching for natural resources,“ said Mike Abrams, ASTER science team leader at NASA’s Jet Propulsion Laboratory. The map is available online to users everywhere at no cost.
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Posted on September 19, 2011 by geography lady
via NASA: Huge Defunct Satellite Will Fall to Earth This Week | Falling NASA Satellite, Upper Atmosphere Research Satellite | Space Junk & Orbital Debris | Space.com.
A dead climate satellite that has been circling Earth for 20 years will make a fiery death plunge this week, with some pieces of the 6 1/2 ton spacecraft expected to reach the surface of the planet, NASA officials say.
The dead satellite orbits at an inclination of 57degrees, which means it crosses every continent except Antarctica. But since oceans cover most of the planet, experts say that’s probable where it will land.
The bus-size Upper Atmosphere Research Satellite, or UARS, will likely plummet down to Earth sometime around Friday (Sept. 23), according to NASA’s latest projections. There is a 1-in-3,200 chance that UARS debris could hit a person, though NASA considers that scenario extremely remote.
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