Monday, March 4, 2013

NASA Earth Observatory Images

For today's posting I decided to include some recent photos taken by astronauts and equipment on the International Space Station.

In January 2013, a new Earth-observing instrument was installed on the International Space Station (ISS). ISERV Pathfinder consists of a commercial camera, a telescope, and a pointing system, all positioned to look through the Earth-facing window of ISS’s Destiny module. ISERV Pathfinder is intended as an engineering exercise, with the long-term goal of developing a system for providing imagery to developing nations as they monitor natural disasters and environmental concerns.
The image above is the “first light” from the new ISERV camera system, taken on February 16, 2013. It shows the Rio San Pablo as it empties into the Golfo de Montijo in Veraguas, Panama. It is an ecological transition zone, changing from agriculture and pastures to mangrove forests, swamps, and estuary systems. The area has been designated a protected area by the National Environmental Authority (ANAM) of Panama and is listed as a “wetland of international importance” under the Ramsar Convention. (Note that the image is rotated so that north is to the upper right.)

Adventurers call Tibet’s Yarlung Tsangpo the “Everest of Rivers” for good reason. Stretches of it are some of the least-explored places in the world, and tales of failed expeditions abound. With headwaters in western Tibet near Mount Kailash, the river has the highest average elevation—4,000 meters (13,000 feet)—of any major river in the world.

For much of the river’s 3,000 kilometer (1,800 mile) course, it flows east through open valleys on the Tibetan Plateau. But at the eastern end of the Himalayas in southeastern Tibet, the river bends sharply, rushes through one of most dramatic gorges in the world, and descends to the lowlands of the Ganges Delta.

The Yarlung Tsangpo gorge is defined by superlatives. Carved into granitic bedrock, it reaches more than 5,300 meters (17,000 feet) from top to bottom in some places, making it three times deeper than the Grand Canyon. It’s also one of the world’s longest canyons, stretching more than 500 kilometers (300 miles).

The image above shows one of the most inaccessible and rugged sections, a part near the canyon entrance where the river passes between two major peaks: the 7,782-meter (25,446-foot) Namcha Barwa and the 7,294-meter (23,462-foot) Gyala Peri.

After maintaining a low simmer for ten months, Italy’s Etna volcano boiled over on February 19–20, 2013, with three outbursts in 36 hours. According to the Italian Istituto Nazionale di Geofisica e Vulcanologia, each outburst (paroxysm) featured “emission of lava flows, pyroclastic flows, lahars, and an ash cloud.”

The Advanced Land Imager (ALI) on the Earth Observing-1 (EO-1) satellite captured Mount Etna on February 19, 2013.  In the image, fresh lava is bright red, as the hot surface emits enough energy to saturate the instrument’s shortwave infrared detectors but is dark in near-infrared and green light. Snow is blue-green because it absorbs shortwave infrared light, but reflects near-infrared and green light. Clouds made of water droplets (not ice crystals) reflect all three wavelengths of light similarly and appear white. Forests and other vegetation reflect near-infrared more strongly than shortwave infrared and green, and so appear green. Dark gray areas are lightly vegetated lava flows, 30 to 350 years old.

This photograph, taken from the International Space Station, highlights one of Japan’s most active volcanoes. Sakurajima began forming approximately 13,000 years ago; prior to 1914, it was an island in Kagoshima Bay. Sakurajima was joined to the mainland by the deposition of volcanic material following a major eruption in 1914.

Several craters lie near the 1,117-meter summit of Sakurajima. The northernmost crater, Kita-dake, last erupted approximately 5,000 years ago; to the south, Minami-dake and Showa craters have been the site of frequent eruptions since at least the eighth century. The ash plume visible near the volcano’s summit may have originated from either Minami-dake or Showa.  This image highlights the proximity of several large urban areas—Aira, Kagoshima, Kanoya, Kirishima, and Miyakonojo—to Sakurajima.

Serpentine cloud shapes snaked across the eastern Pacific Ocean in mid-January 2013. The Moderate Resolution Imaging Spectroradiometer (MODIS) on NASA’s Aqua satellite captured this natural-color image on January 15, 2013, showing an area off of the west coast of the United States and Canada.

Part of the United Arab Emirates, the resort town of Dubai entered a period of dramatic urbanization at the beginning of the twenty-first century. Lacking oil, Dubai built its growth on finance, real estate, and tourism. With no surface water, few aquifers, and little rainfall, the city used desalinization plants to convert ocean water to freshwater, ornamenting the city with golf courses, gardens, and palm trees. Gigantic palm trees also sprouted along the coast—artificial islands made from sea-floor sand protected by rock breakwaters.

This image of the United States of America at night is a composite assembled from data acquired by the Suomi NPP satellite in April and October 2012. The image was made possible by the new satellite’s “day-night band” of the Visible Infrared Imaging Radiometer Suite (VIIRS), which detects light in a range of wavelengths from green to near-infrared and uses filtering techniques to observe dim signals such as city lights, gas flares, auroras, wildfires, and reflected moonlight.

The giant iceberg that broke off Greenland’s Petermann Glacier in mid-July 2012 continued moving down the fjord at the end of the month. The Moderate Resolution Imaging Spectroradiometer (MODIS) on NASA’s Terra satellite captured this natural-color image on July 30, 2012.
By the time MODIS acquired this image, the iceberg—named PII-2012—had traveled roughly 22 kilometers (14 miles) from the edge of the Petermann Glacier and had rotated counter-clockwise. The iceberg’s speed had increased from 1 kilometer per day to 2 kilometers per day.

This astronaut photograph highlights part of Lake Powell, which extends across southeastern Utah and northeastern Arizona. Lake Powell started filling in 1963 when the Glen Canyon Dam was completed along the Colorado River in Arizona, and the canyon was flooded. The serpentine surface of the reservoir—highlighted by gray regions of sunglint—follows the incised course of the canyon, which was cut downwards into the existing rock layers by the erosive power of the river. The two branches shown in the image are connected by a bend to the southwest (not shown).

Lake Powell is part of the Glen Canyon National Recreation Area, which extends for more than 300 kilometers (186 miles) along the shoreline and side canyons. The primary intended use of Lake Powell’s water is support for agriculture, with a small portion allocated to urban use in Arizona, Nevada, and California.

The reservoir did not reach its maximum capacity of 27 million acre-feet until 1980. More recently, extended drought conditions in the southwestern United States have resulted in a significant lowering of the lake water level and the emergence of formerly submerged parts of Glen Canyon. Should average precipitation in the Colorado River watershed decrease (as predicted by regional climate change models), that could result in further lowering of Lake Powell and changes to the water management plans.

Fluctuations in water levels and changes in river courses are a common occurrence in the geologic record of rivers. Looking somewhat like a donut or automobile tire from the vantage point of the International Space Station, The Rincon (image center) is an entrenched and abandoned meander, or loop, of the Colorado River.

NASA /  NASA Marshall Space Flight Center,  NASA EO-1 team,

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