ISS012-E-5172
The Navajo Mountain region has special cultural significance to the Navajo people, who know it as Naatsis’áán (Earth Head). Together with Rainbow Bridge to the northwest (approximate location shown), Navajo Mountain figures prominently as the first settlement area in western Navajo origin stories. Following the military defeat of the Diné (Navajo) by United States forces in 1863, the political landscape was changed by new boundaries and major physical alterations. The establishment of Rainbow Bridge National Monument (1910), and the filling of Glen Canyon by Lake Powell in 1963 (upper right), has facilitated tourism and aesthetic appreciation of this previously remote region. Access to Navajo Mountain is still regulated by the sovereign Navajo Nation, and a permit is required to hike in the region.
ISS012-E-5727
Large areas of plankton production occur at about 40 degrees South latitude along the convergence zone—known as the Subtropical Front—between the Antarctic Circumpolar Current and subtropical waters. The converging of the different water masses mixes and disperses nutrients, with plankton blooms appearing when spring lighting becomes strong enough. The convergence zone extends generally east-west at about the latitude of Cook Strait, which divides New Zealand’s North and South Islands (not visible). Satellite imagery shows that the plankton blooms in this image extended fully 8 degrees of longitude eastward, past the Chatham Islands.
Smaller, brightly colored eddies along the coastline are sediment plumes generated by wave action and supplied by rivers. The coastal sediment patterns reveal the precise location of the convergence zone. Castlepoint marks a change in coastline orientation but also a change in nearshore current direction: south of Castlepoint sediment is moved by the north-flowing Antarctic Circumpolar Current. But north of Castlepoint, nearshore sediment is transported southwards by currents in the subtropical waters, before being caught up in the Antarctic Circumpolar Current (arrows indicate current directions).
ISS012-E-6456
This astronaut photograph features the northern end of the salar and the dormant volcano Mount Tunupa (image center). This mountain is high enough to support a summit glacier, and enough rain falls on the windward slopes to provide water for small communities along the base. The dark volcanic rocks comprising Mt. Tunupa are in sharp contrast with the white, mineral-crusted surface of the salar. The major minerals are halite—common table salt—and gypsum—a common component of drywall.
Relict shorelines visible in the surface salt deposits (lower right of the image) attest to the occasional presence of small amounts of water in the salar. Sediments in the salar basin record fluctuations in water levels that occurred as the lake that once occupied the salar evaporated. These sediments provide a valuable paleoclimate record for the region. The dynamic geological history of the Altiplano is recorded in isolated “islands” within the salt flat (image left); these islands are typically built from fossil coral reefs covered by Andean volcanic rocks.
ISS012-E-7151
Cabo San Lucas, once just a collection of fishing villages, is now a tourist hotspot (current population 41,000), known for its mild, sunny winter weather. It has grown rapidly in the past few decades, with new neighborhoods sprawling north and northwest (indicated with lines) along major roads. Larger developments stretch northeast along the coast for 40 kilometers from Cabo San Lucas to the slightly larger city of San José del Cabo (not visible). Whale watching competes with marlin fishing as one of the area’s most popular activities.
ISS012-E-9567
While much of the Ship Channel is associated with heavy industry, two icons of Texas history are also located along its length. The inset (area denoted by white rectangle) highlights the battleship USS Texas and the San Jacinto Monument. The Texas saw service during both World Wars, and is the last remaining example of a dreadnought-class battleship in existence. The nearby San Jacinto Monument commemorates the 1836 battle in which Texas won its independence from Mexico. The monument itself is a 570-foot-high (173-meter) shaft topped by a 34-foot-high (10-meter) star, making it 15 feet (5 meters) higher than the Washington Monument in Washington, D.C.
The Houston Ship Channel has been periodically widened and deepened to accommodate ever-larger ships, and is currently 530 feet wide by 45 feet deep by 50 miles long (161 meters by 14 meters by 80 kilometers). The islands in the ship channel are part of the ongoing widening and deepening project. The islands are formed from soil pulled up by dredging, and the salt marshes and bird islands are part of the Houston Port Authority’s beneficial use and environmental mitigation responsibilities.
ISS012-E-11654
Following the initial flooding, a pumping station and canal were constructed in 2000 to maintain water flow into the region, allowing for industrial and agricultural development in the desert. This view shows the completed Mubarek Pumping Station on Lake Nasser, the spillway that originally flooded the Toshka depression, the southern end of the first of the Toshka Lakes, part of the 50-kilometer-long main canal (the Sheikh Zayed Canal), side canals, and several new fields in the Egyptian desert northwest of Lake Nasser. Astronauts, cosmonauts, and space-based sensors have been monitoring these developments in Egypt since their inception in the late 1990s. The New Valley’s Toshka Lakes, and the new developments surrounding them, represent one of the most visible and rapid man-made changes on the Earth’s surface.
ISS012-E-8962
Shallow water surrounds Cayo Largo, evidenced by the lighter shade of blue around the island’s perimeter. While the water south of the island appears clear enough to reveal the underlying ocean floor, the water on the north side of the island is cloudy. This cloudy water indicates that sediment is washing off the land surface and into the water or is being stirred up from the shallow sea floor.
Cayo Largo is a limestone island, formed over millions of years from the remains of marine organisms, such as the ones that build coral reefs. Living coral reefs form one more attraction for tourists on this island, although coral bleaching has stressed some reef communities in the Caribbean. The northern coast of Cayo Largo consists largely of mangroves and salt pans.
ISS012-E-11639
This image documents recent drops in water levels in the Toshka Lakes region of Egypt. The Toshka Lakes and the New Valley surrounding the lakes constitute a major Egyptian project to claim a huge area of desert for agriculture and industry by diverting Nile River water from Lake Nasser. The initial flooding occurred in the late 1990s, when Lake Nasser water levels were at an all-time high. The flooded regions of the Toshka Lakes west of Lake Nasser have decreased greatly over the years, exposing the former dune fields (dunes appear as islands in the lake and along the shoreline of the top image), and leaving a “bath-tub ring” of wetlands (dark region) surrounding the lake shorelines. As both the drought and development continue, this region of Egypt is sure to change.
ISS012-E-13692
This astronaut photograph captures a 25-kilometer long smoke plume from a fire in the Upper Ouachita National Wildlife Refuge in northeastern Louisiana. The fire started at approximately 1:00 p.m. on January 2, 2006, and this image was acquired approximately three and a half hours later as the International Space Station passed over the Texas-Louisiana border, to the southwest of the scene. The long extent of the plume reflects the strong westerly winds that drove the fire eastwards and damaged an estimated 200-300 acres of the wildlife refuge. The striking illumination of the plume is caused by a very low sun angle (the angle between the horizon and the Sun at the point on the ground directly below the Space Station). Although the plume is well illuminated, the low sun angle results in low illumination of other scene features, such as agricultural fields adjacent to the refuge.
ISS012-E-11779
A low barrage (lower left) dams the Caroní as a water supply for the city. The Orinoco River is a muddy brown, carrying sediment produced by erosion of the Andes Mountains far to the southwest. By contrast, the Caroní is clear blue, as it drains the ancient landscapes of the Guyana Highlands, where erosion is much slower. As at the famous confluence of the muddy Amazon and clear Negro rivers in Amazonia, a mixing zone can be seen in the middle of this image. The clear Caroní water produces a less muddy zone for tens of kilometers downstream of the confluence (this part of the Orinoco flows almost due east, left to right).
