Some cool earth image images:
Toshka Lakes, Egypt (NASA, International Space Station, 06/21/12)
Image by NASA's Marshall Space Flight Center
Toshka Lakes in southern Egypt are featured in this image photographed by an Expedition 31 crew member on the International Space Station. The Toshka Lakes (center) were formed in the Sahara Desert of Egypt by water from the River Nile conveyed from Lake Nasser by a canal to the Toshka Depression. Flooding of the Toshka Depression had created the four main lakes with a maximum surface area in 2002 of approximately 1,450 square kilometers -- around 25.26 billion cubic meters of water. By 2006 the stored water was reduced by 50 per cent and by 2012 shows open water only in the lowest parts of the main western and eastern basins—representing a reduction in surface area to 307 square kilometers -- nearly 80 per cent smaller than the 2002 surface area. Standing water is almost completely absent from the central basin. From space, astronauts documented the first lake -- the easternmost one -- in 1998. The lakes progressively grew in depressions to the west, the westernmost filling between 2000 and 2001. This image shows lines of center-point agricultural fields near the east-basin lake nearest Lake Nasser. Sunglint on the western lake makes the water surface appear both light and dark, depending on which parts of the surface were ruffled by the wind at the moment the image was taken.
Image credit: NASA/JSC
Original image:
spaceflight.nasa.gov/gallery/images/station/crew-31/html/...
More about space station research:
www.nasa.gov/mission_pages/station/research/index.html
There's a Flickr group about Space Station Research. Please feel welcome to join! www.flickr.com/groups/stationscience/
View more than 400 photos like this in the "NASA Earth Images" Flickr photoset:
www.flickr.com/photos/28634332@N05/
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These official NASA photographs are being made available for publication by news organizations and/or for personal use printing by the subject(s) of the photographs. The photographs may not be used in materials, advertisements, products, or promotions that in any way suggest approval or endorsement by NASA. All Images used must be credited. For information on usage rights please visit: www.nasa.gov/audience/formedia/features/MP_Photo_Guidelin...
Etosha Pan, Namibia (NASA, International Space Station, 12/30/11)
Image by NASA's Marshall Space Flight Center
The Etosha Pan in Namibia is featured in this image photographed by an Expedition 30 crew member on the International Space Station. This photograph shows the white, salt-covered floor of the northwest corner of the great dry lake in northern Namibia known as the Etosha Pan (left margin). Two rivers, the Ekuma and Oshigambo, transport water from the north down to the Etosha Pan proper. In a relatively rare event, water from recent rains has flowed down the larger Ekuma River—in which it appears as a thin blue line within the generally light grey-green floodplain—and fills a lobe of the lake with light green water (lower right quarter of image). Water has also flowed into a small offshoot dry lake where it appears a brighter green (upper right quarter of image). Other smaller lakes at center and top center show red and brown water colors. The different colors of lake water are determined by the interplay of water depth and resident organisms such as algae; the algae color varies depending on water temperature and salinity. A similar process is observed in pink and red floodwaters ponded in Lake Eyre, a usually dry lake in Australia's arid center. In this case it is known that the coloration is indeed due to algae growth. Typically, little river water or sediment reaches the floor of the Etosha dry lake because water seeps into the riverbeds along their courses. The floor of the pan itself is seldom seen with even a thin sheet of water. In this image, there was enough surface flow to reach the pan, but too little to flow beyond the inlet bay. A prior flood event, when water entered the pan via the Oshigambo River, was documented in astronaut imagery in 2006. The straight line that crosses the image from top center to bottom is the northern fence line of Namibia's Etosha National Park. This straight, three-meter-high fence keeps wildlife from crossing into the numerous small farms of the relatively densely populated Owambo region of Namibia, north of the pan. The large Etosha dry lakebed (120 kilometers or 75 miles long) is the center of Namibia's largest wildlife park, a major tourist attraction.
Image credit: NASA
Original image/read the blog:
spaceflight.nasa.gov/gallery/images/station/crew-30/html/...
More about space station research:
www.nasa.gov/mission_pages/station/research/index.html
There's a Flickr group about Space Station Research. Please feel welcome to join! www.flickr.com/groups/stationscience/
View more than 400 photos like this in the "NASA Earth Images" Flickr photoset:
www.flickr.com/photos/28634332@N05/
_____________________________________________
These official NASA photographs are being made available for publication by news organizations and/or for personal use printing by the subject(s) of the photographs. The photographs may not be used in materials, advertisements, products, or promotions that in any way suggest approval or endorsement by NASA. All Images used must be credited. For information on usage rights please visit: www.nasa.gov/audience/formedia/features/MP_Photo_Guidelin...
Great Sand Sea, Egypt (NASA, International Space Station, 05/11/12)
Image by NASA's Marshall Space Flight Center
Linear dunes in the Great Sand Sea in southwest Egypt are featured in this image photographed by an Expedition 31 crew member on the International Space Station. In southwestern Egypt, deep in the Sahara Desert, the action of wind dominates landscapes today much as it has done for the past several thousand years. Winds blowing from the north have fashioned sands into large dunes, aligned parallel with these winds. The so-called linear dunes - shown here in the Great Sand Sea - are easily seen from space and local maps show that they rise 20--30 meters above the surrounding flat plains. The distance between individual linear dunes is interestingly regular, at 1.5--2.5 kilometers, suggesting some equilibrium exists between the formative wind strength and the sand supply. It is possible that linear dunes may relate to earlier times when winds were stronger than they are today, or sand more plentiful. The dark patch of rock outcrop at upper right sticks up above the surface on which the dunes lie by as much as 150 meters. The north winds have been deflected around this high zone, and smaller secondary linear dunes can be seen along the right side of the image, aligned with local winds that become ever more northeasterly with nearness to the outcrops. A dune-free zone on the protected downwind (south-southeast) side of the outcrop gives a sense of the sand movement (generally from the bottom of the image towards the top). At first glance, the large linear dunes appear to be the major landform in the image; however a complex pattern of even smaller dunes can be seen perched on top of the largest dunes (inset). The sand that comprises many dune fields usually, according to scientists, derives from some larger river not very distant upwind, supplied from the dry river bed (exposed to the wind during dry seasons of low river flow, or regional change to a more arid climate). Inland dune fields thus lie downwind of the source river. A large, unnamed river once flowed to the Mediterranean Sea situated west of the dunes shown in this picture, dumping its sand load 300 kilometers northwest of the area shown. It is likely that this river, the evidence of which is now almost completely obliterated, was the source of the sand in the linear dunes, the scientists say.
Image credit: NASA/JSC
Original image:
spaceflight.nasa.gov/gallery/images/station/crew-31/html/...
More about space station research:
www.nasa.gov/mission_pages/station/research/index.html
There's a Flickr group about Space Station Research. Please feel welcome to join! www.flickr.com/groups/stationscience/
View more than 400 photos like this in the "NASA Earth Images" Flickr photoset:
www.flickr.com/photos/28634332@N05/
_____________________________________________
These official NASA photographs are being made available for publication by news organizations and/or for personal use printing by the subject(s) of the photographs. The photographs may not be used in materials, advertisements, products, or promotions that in any way suggest approval or endorsement by NASA. All Images used must be credited. For information on usage rights please visit: www.nasa.gov/audience/formedia/features/MP_Photo_Guidelin...
