ISS009-E-9954
The narrow Strait of Gibraltar is the gatekeeper for water exchange between the Atlantic Ocean and Mediterranean Sea. A top layer of warm, relatively fresh water from the Atlantic Ocean flows eastward into the Mediterranean Sea. In return, a lower, colder, saltier layer of water flows westward into the North Atlantic ocean. A density boundary separates the layers at about 100 m depth.
Like traffic merging on a highway, the water flow is constricted in both directions because it must pass over a shallow submarine barrier, the Camarinal Sill. When large tidal flows enter the Strait, internal waves (waves at the density boundary layer) are set off at the Camarinal Sill as the high tide relaxes. The waves—sometimes with heights up to 100 m — travel eastward. Even though the waves occur at great depth and the height of the waves at the surface is almost nothing, they can be traced in the sunglint because they concentrate the biological films on the water surface, creating slight differences in roughness.
In this image, the tidal bore creates internal waves (top arrow) that propagate eastward and expand outward into the Mediterranean in a big arc (near bottom). Other features can be traced in the sun’s reflections. Linear and V-shaped patterns (bottom arrow) are wakes of ships, providing evidence for the heavy ship traffic through the narrow waters between Spain and Morocco.
Water features in the sunglint pattern appear to the astronaut to be extremely transient, visible only briefly (a few seconds) as the spacecraft passes rapidly overhead. Photographs from space of the ocean sunglint pattern are a tool for studying physical oceanographic and atmospheric processes and other phenomena that affect surface roughness.
references:
Internal
Waves, Strait of Gibraltar
Christopher O. Tiemann, Peter F.
Worcester, Bruce D. Cornuelle, Effects
of Internal Waves and Bores on Acoustic Transmissions in the Strait
of Gibraltar, Conference Proceedings from Internal Solitary Wave
Workshop, Victoria, B.C., Canada, October 1998. Woods Hole
Oceanographic Institution Technical Report WHOI-99-07
Oceanography from the Space Shuttle, Solitons,
Gibraltar
ISS009-E-5953
The natural history of the region includes thousands of years of human occupation; it is the aboriginal homeland of the O‘Odham tribe, also known as the Papago. The region also served as an early training site for Apollo astronauts in the 1960s. This ecosystem supports a wonderfully diverse northern Sonoran desert assemblage of plants and animals, including large saguaro cacti, ocotillo, many species of reptiles, amphibians, and insects. In fact, the name Pinacate is derived from “pinacatl,” the Aztec name for the desert stink beetle, which is common in the region. The natural and cultural resource management of the region, including the archeological sites and the high biodiversity, is now guaranteed: the site was declared a UNESCO Biosphere Reserve in 1993.
Early in May 2004, the new Space Station crew (ISS-9) obtained high-resolution images of the Pinacates, allowing for detailed observations of the surface features. One example is a large volcanic crater (see box, and detail in image ISS009-E-5944) called Crater Elegante which is one of the most prominent and interesting features of the Pinacates. For scale, the diameter of the crater is approximately 1500 meters. Such detailed images can be used to monitor vegetation and development in the region.
ISS009-E-5944
The natural history of the region includes thousands of years of human occupation; it is the aboriginal homeland of the O‘Odham tribe, also known as the Papago. The region also served as an early training site for Apollo astronauts in the 1960s. This ecosystem supports a wonderfully diverse northern Sonoran desert assemblage of plants and animals, including large saguaro cacti, ocotillo, many species of reptiles, amphibians, and insects. In fact, the name Pinacate is derived from “pinacatl,” the Aztec name for the desert stink beetle, which is common in the region. The natural and cultural resource management of the region, including the archeological sites and the high biodiversity, is now guaranteed: the site was declared a UNESCO Biosphere Reserve in 1993.
Early in May 2004, the new Space Station crew (ISS-9) obtained high-resolution images of the Pinacates, allowing for detailed observations of the surface features. One example is a large volcanic crater (see box in image ISS009-E-5953, and detail in current image) called Crater Elegante which is one of the most prominent and interesting features of the Pinacates. For scale, the diameter of the crater is approximately 1500 meters. Such detailed images can be used to monitor vegetation and development in the region.
ISS009-E-5725
ISS009-E-23892
ISS009-E-22625
Imagery of the region from the International Space Station includes seasonal observations—this image shows the volcano near the southern hemisphere spring equinox. The lake, just east of Maipo’s peak, is still ice covered. However, the increasing temperatures of spring are suggested by a muddy-looking streak near the lower left corner. The streak appears to be a landslide or avalanche that flowed westward down a rugged slope, possibly triggered by instability in the snowpack due to snow melt.
ISS009-E-28346
The main features visible in this image are the result of a cataclysmic 1980 eruption resulting from landslide failure of the northern flank of the volcano. The resulting directed blast of suddenly exposed gas-rich magma devastated a region of 20 km to the north and raised the bed level of Spirit Lake by 60 meters. The grayish Pumice Plain is mainly comprised of pyroclastic and mudflow deposits from the 1980 eruption. Today, the volcano is being intensively monitored by United States Geological Survey scientists for indications of further increases in activity and hazard potential.
ISS009-E-15488
It is the vast quantity of sediment eroded from the Andes Mountains that gives the Solimões its tan color. By comparison, water in the Negro derives from the low jungles where reduced physical erosion of rock precludes mud entering the river. In place of sediment, organic matter from the forest floor stains the river the color of black tea.
The Solimões provides nutrient-rich mud to lakes on the floodplain (lower right). The ecology of muddy lakes differs correspondingly from that of nutrient-poor, blackwater rivers and lakes. Solimões water can be seen leaking into the Negro west of the main meeting zone (lower left). The Solimões is much shallower than the Negro because it has filled its valley and bed with great quantities of sediment since the valleys were excavated. Indeed, widths of the rivers differ for this reason (the Negro River is almost 20 km wide in the top left corner).
ISS009-E-23808
Close to shore, fringing reefs border the coastline. Farther offshore grows a larger, more complicated barrier reef structure. Different parts of the reef structure show up as variable shades of light blue. Deeper water channels (darker blue) define the boundaries for individual reefs within the greater barrier reef system. Such a complex pattern of reefs may translate into greater ecosystem diversity because of the wide variety of local reef environments.
ISS009-E-18679
The dark regions running along the coast are the wetlands, which support high biodiversity due to the unique environment and relative isolation of the Caspian Sea. The coastal wetlands are especially important to migrating birds as an important stop-over along the Asian flyway.
The Ural River’s trek to the Caspian is long —roughly 2,400 kilometers (1,500 miles) southward from the Ural Mountains in Russia to empty into the northern Caspian Sea in Kazakhstan. Although the current sea level of the Caspian is more than 26 meters below global mean sea level, the water levels have risen roughly 2 meters since 1980. This increase has caused flooding of much of the coastal region, including the Ural Delta, and it endangers these coastal wetland environments. The coastal flooding has also impacted the oil exploration infrastructure bordering the Caspian coastline.
