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The point of maximum sunglint in this image is centered within Cape Cod Bay, the body of water partially enclosed by the “hook” of Cape Cod in Massachusetts (image right). (The U.S. Congress authorized the creation of Cape Cod National Seashore fifty years ago, in August 1961). Sunglint off the water provides sharp contrast with the coastline and the nearby islands of Martha’s Vineyard and Nantucket, both popular destinations for tourists and summer residents. To the north, rocky Cape Ann extends into the Atlantic Ocean; the border with New Hampshire is located approximately 30 kilometers (18 miles) up the coast.
Further to the west, the eastern half of Long Island, New York, emerges from extensive cloud cover over the mid-Atlantic and Midwestern States. Persistent storm tracks had been contributing to record flooding in the Midwest at the time this image was taken in late June 2011. Thin blue layers of the atmosphere, contrasted against the darkness of space, are visible along the Earth’s curvature at image left.
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This oblique, northwest-looking view from July 2011, at the end of the dry season, shows the extent of the smoke on the African plateau—from central Zimbabwe (image lower left) to northern Malawi more than 1,000 kilometers away (image top right), and in the wide coastal plains of the lower Zambezi River valley of Mozambique (image lower right). Here smoke can be seen blowing inland, channeled up the Zambezi River valley and contributing to the pall on the plateau. The light gray smoke plumes contrast with higher altitude, brighter patchy cloud cover at image lower right.
The smoke palls obscure the details on the land surface so that Lake Malawi, one of Africa’s Great Lakes, is barely visible. The same goes for Lake Cahora Bassa, Africa’s fourth largest reservoir, in the Zambezi valley. The sun’s reflection off the surface of Lake Kariba makes it prominent in the view at image left. Kariba is 220 kilometers long and is the world’s largest artificial reservoir by volume. The steep, shadowed, mid-afternoon faces of the Inyanga Mountains on the Mozambique-Zimbabwe border protrude above the smoke layer at image lower left. Solar panels extending from Russian spacecraft docked at the International Space Station are visible at image left.
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Today, Crete is the largest and most heavily populated island of Greece (or the Hellenic Republic). The island stretches approximately 260 kilometers (161 miles) from west to east, and it is roughly 60 kilometers (37 miles) across at its widest point. The rugged terrain of Crete includes mountains, plateaus, and several deep gorges. The largest city on the island, Heraklion, sits on the northern coastline.
Several smaller islands ring Crete. Two of the largest of these, Dia and Gavdos, are sparsely populated year-round, although Gavdos hosts numerous summer visitors.
The western and central parts of Crete appear surrounded by quicksilver in this astronaut photograph taken from the International Space Station. This phenomenon is known as sunglint, caused by light reflecting off of the sea surface directly toward the observer. The point of maximum reflectance is visible as a bright white region to the northwest of the island. Surface currents causing variations in the degree of reflectance are visible near the southwestern shoreline of Crete and the smaller island of Gavdos (image lower left).
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From an astronaut’s perspective in low-Earth orbit, land surfaces usually appear brighter than water. But in this image, reflected sunlight, or sunglint, inverts this pattern. The light has a coppery hue, perhaps due to smog particles in the air, which can enhance the red part of the spectrum. More likely, the color comes from the angle of sunlight around dawn.
The camera settings used to acquire sunglint images result in high contrast, which reveals the fine detail of coastlines and surface features of water bodies, while masking land surface details. The thin, 50 kilometer (30 mile) barge canal leading from the Baltic to Kaliningrad is visible, but the great port of Kaliningrad itself is not. Other human patterns on this intensively developed landscape—such as towns, highways and farm boundaries—are likewise masked.
The area has a long human history. The growth of the Vistula spit finally cut off the north Polish city of Elblag (just beyond the bottom of the image) from the Baltic Sea in the 13th century. To reconnect Elblag with the Baltic Sea, the European Union is considering whether to fund the creation of another canal through the spit at image lower right, despite ecological concerns.
As the only Russian port on the Baltic Sea to be ice-free year-round, Kaliningrad gained strategic importance as home of the Baltic Fleet in the mid-20th century. The city’s 750th anniversary was celebrated in 2005, with increasing use of its original name, Koenigsberg, reflecting the return of older names for cities.
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This photograph from the International Space Station (ISS) was taken with a short camera lens, providing the large field of view. To give a sense of scale, the centers of the London and Paris metropolitan areas are approximately 340 kilometers (210 miles) from each other. The image is also oblique—taken looking outwards at an angle from the ISS, which tends to foreshorten the image—making the distance between Paris and Milan (640 kilometers, or 400 miles) appear less than that of Paris to London.
In contrast to the land surface defined by the city lights, the English Channel presents a uniform dark appearance. Similarly, the Alps near Milan are also largely devoid of lights. While much of the atmosphere was clear at the time the image was taken, the lights of Brussels are dimmed by thin cloud cover.
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A striking feature is the line of lights, with a distinctly orange hue, snaking across the center of the image. It appears to be more continuous and brighter than most highways in the view. This is the fenced and floodlit border zone between India and Pakistan. The fence is designed to discourage smuggling and arms trafficking. A similar fenced zone separates India’s eastern border from Bangladesh (not visible).
This image was taken with a 16 mm lens, which provides the wide field of view, as the International Space Station (ISS) was tracking towards the southeast across India. The ISS crew took the image as part of a continuous series of frames, each with a one-second exposure time to maximize light collection. Unfortunately, this also causes blurring of some ground features.
The distinct, bright zone above the horizon (visible at image top) is airglow, a phenomena caused by excitation of atoms and molecules high in the atmosphere (above 80 kilometers, or 50 miles altitude) by ultraviolet radiation from the Sun. Part of the ISS Permanent Multipurpose Module and a solar panel array are visible at image right.
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Record-setting drought conditions have affected much of Texas since early 2011, drying out both forest and grassland and providing ample fuel for wildfires. Relatively high winds and low humidity levels have also contributed to the rapid spread and expansion of fires. According to a report dated September 7, 2011, the Texas Forest Service had responded to 172 fires affecting an area of 546.53 square kilometers (135,051 acres) over the preceding seven days. Fires near Bastrop (to the east of Austin) had destroyed 785 homes as of September 7, 2011.
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The present-day Owens Lake was once part of a much larger lake and river system along the northeastern border of California and Nevada during the Pleistocene Epoch (about 3 million to 12,000 years ago). Melt water from alpine glaciers in the Sierra Nevada filled the regional valleys of the Basin and Range to form glacial lakes—ancestors of the now-dry lakebeds (or playas) of Owens, Searles Lake, and China Lake.
While Searles and China Lakes dried out because of regional changes to a hotter and drier climate, Owens Lake became desiccated largely due to the diversion of the Owens River in the early 20th century to serve the needs of Los Angeles, 266 kilometers (165 miles) to the south. Following complete desiccation of the lakebed in 1926, significant amounts of windblown dust were produced. Residents of the now largely abandoned town of Keeler (on the eastern side of the lake) coined the term “Keeler fog” to describe the airborne dust.
In addition to adverse health effects on local residents, dust from Owens Lake has been linked to reductions of visibility in nearby national parks, forests, and wilderness areas. Recently, the City of Los Angeles has undertaken efforts to control dust evolution from the lakebed.
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Tan, linear dunes at image center (on the south side of the Irtysh River) dominate the view. The dunes are formed from mobile barchan (crescent-shaped) dunes moving from left to right in this view. The barchans eventually merge to form the large, linear dunes which can reach 50 to 100 meters (165 to 330 feet) in height. Sand moving along the southern edge of the field appears to be feeding a southeastern lobe with a separate population of linear dunes (image lower right).
The Burqin-Haba River-Jimunai Desert area also includes darker gravel-covered surfaces that form pavements known locally as gobi. At the resolution of an astronaut photograph, these are somewhat indistinguishable from the vegetated areas arresting some of the dunes. But gobi tend to be located on the flat regions between the dunes.
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Astronauts on the International Space Station used a digital camera to capture this view of Petermann Ice Island A, fragment 2, off of the northeast coast of Newfoundland on August 29, 2011. Spanning roughly 4 kilometers by 3.5 kilometers (2.5 by 2 miles), the ice island is covered with melt ponds and streams, much as the surface of Greenland looks in mid-summer.
As ice melts on top of the Greenland ice sheet, the melt water forms streams and pools in the depressions on the ice surface. Drawn downslope by gravity—much like streams on a mountainside—water also runs toward the edges of the ice. In some cases, it cracks through it and rushes to the bottom. Such processes appear to be at work on the ice island as well.
August 2011 was a busy month in the life of the ice island, according to the Canadian Ice Service. On August 7, it became grounded on a shoal or shallow seafloor off of St. Anthony, Newfoundland, where it sat for 11 days. By August 18, the ice island broke free and began drifting again, only to split into two large pieces about five days later. The Ice Service last reported on it on August 25.
References
Canadian Ice Service (2011) Petermann Ice Island Updates. Accessed September 16, 2011.
NASA Earth Observatory (2011, June 25) Ice Island off Labrador.
