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This astronaut photograph depicts the downtown district of Al Balad, a residential area historically (and presently) occupied by wealthy merchants. A major roadway running along the coast, Corniche Road, is a locus for Jeddah nightlife, restaurants, and shopping centers. In addition to urban attractions, coral reefs along the coast (north-south trending islands at image left) are frequented by divers visiting the city. The image captures the multicolored rooftops of homes and other buildings in the city, the oldest of which were built using coral from the nearby Red Sea and clay from the al-Manqabah lagoon in the center of the Al Balad district (center of image; lagoon is approximately 0.25 kilometers across).
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This astronaut photograph captures the northwestern portion of the metropolitan area. Standing water bodies such as Lake Lewisville and Grapevine Lake are highlighted by sunglint, where the surface of the water acts as a mirror reflecting sunlight back towards the astronauts in the International Space Station (read Sunglint in Astronaut Photography of Earth for a more detailed explanation of sunglint). Using the sunglint to define edges of water helps when mapping water bodies and stream courses on a landscape—note the region of small ponds to the north of Grapevine Lake highlighted by sunglint. Images such as these help characterize surface hydrology and areas of potential flooding hazard.
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An earlier image, shot by astronauts with a handheld camera in 2003, shows the outline of the palm nearing completion. Two years later, the palm appears in its all its glory to passing space travelers. It has so far required over 50 million cubic meters of sand to raise it above the sea surface. Palm Island is the last of three major developments designed to transform the Dubai coastline into a major coastal metropolitan area and tourist destination. When completed, the resort is expected to support a population of approximately 500,000 people.
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In this astronaut photograph taken from the International Space Station, the water of Lake Nasser stands out from its surroundings due to sunglint. The Sun’s light reflects off the water’s surface and into the camera lens, giving Lake Nasser an iridescent sheen. Sunglint is a common phenomenon in satellite images as well as astronaut photographs.
The Aswan High Dam, which created this massive lake, is the newer of two dams in the vicinity. The older of these dams is known as the Aswan Low Dam, or simply the Aswan Dam. Completed in 1902, the older dam had nearly overflowed by the middle of the 20th century, despite having been raised twice. Instead of raising it a third time, officials chose to build the Aswan High Dam upriver in the 1960s. The dam proved to be a mixed blessing, providing some residents with irrigation and drinking water, but forcing thousands of others to relocate to higher ground.
The Aswan High Dam ultimately proved much more effective than its predecessor, so effective that the dam’s construction spawned another massive effort. The ancient Egyptian temple of Abu Simbel lay in the path of the rising waters produced by the new dam. In the 1960s, the historical site was literally taken apart piece by piece and reassembled in a new place to avoid submersion. The Aswan High Dam has not, however, proven immune to overflowing. High levels of rainfall led to new lakes in the region in the late 1990s.
The name of Lake Nasser technically refers only to the portion of this lake in Egypt. The Sudanese prefer to call their portion of the lake Lake Nubia.
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The Crew Earth Observations team selects science targets and uploads them to the ISS crew daily based on the current orbital position of the ISS, local sun angle, predicted local weather conditions, and the task schedule. Satellites, such as Landsat and Terra, that are in polar (pole-to-pole) orbits pass over the same location on the globe at approximately the same time every day. The inclined (angled), equatorial orbit of the ISS and having a “human in the loop” to point the camera allow for a wide variety of local sun angles and ground resolutions (levels of detail) for science targets. These unique characteristics of astronaut photography provide a dataset that includes both scientific and aesthetic, or artistic, value. This duality is expressed in ISS Expedition 10 Commander Leroy Chiao’s ten favorite photos (see also Expedition 10 Earth Observation Photos; and Shooting for the Heart: Astronaut Finds Passion for Photography in Space).
Two of the world’s great cities, New York and Beijing, were among those imaged by Leroy Chiao during Expedition 10. Large urban centers such as these serve as global economic, social, and cultural centers. The establishment and growth of cities also alters local and sometimes regional climate patterns, hydrology, and ecology. Replacement of existing soil and vegetation by asphalt and concrete fosters the creation of urban “heat islands,” increases surface water runoff, decreases groundwater recharge, and fragments pre-existing ecosystems.
While cities represent people’s most visible alteration of Earth’s surface, numerous other regions of the planet are also directly or indirectly impacted by human activities. Photography of glaciers, deserts, coastal regions, and lakes provide data for tracking changes. Astronauts document the advance and retreat of glacial ice due to climate change; location and structure of dune fields related to desertification; changes to coastlines and deltas following hurricanes or human development; and changes to lakes and rivers related to land cover and land use change. Digital astronaut photographs only record data in the visible red, green, and blue wavelengths of light (not infrared, for example), but the variety of acquisition times and spatial resolutions make these data useful additions to more traditional multispectral and hyperspectral datasets from satellites and other remote-sensing platforms like aircraft.
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Female sea turtles return to the same beaches where they were hatched to lay their eggs. They prefer sandy beaches with easy access to deep water. This photo shows why the turtles would choose the southeastern beaches: the barrier reef is diminished in the area compared to the north side of the island, and the water is deeper (darker blue). The females scoop a nest out of the sand, lay their eggs, and cover them. When the hatchlings emerge from their eggs, moonlight glinting off the sea guides them to the water.
White dots scattered across most of the island reveal the extent of development. Residential and tourist development consumes turtle nesting beaches. The presence of people, especially at night, can cause females to abort nesting attempts or to abandon eggs. Artificial lights can disorient the hatchlings as they emerge form their nests. Prior to a nighttime beach patrol and monitoring program operated by the Nature Conservancy, poaching of turtle eggs was also a problem on East End beaches.
