Uluru

An astronaut aboard the International Space Station (ISS) photographed this iconic landscape while orbiting over Australia’s aptly-named “red center.” Seen from ground level, this majestic sandstone rock formation stands 348 meters (1,120 feet) tall and is 3 kilometers (1.85 miles) long. Uluru is the ancient name used by Indigenous Australians; Ayers Rock is the name that was given to the landform by explorer William Christie Gosse in the 1800s.

Uluru is one of Australia’s major tourist attractions (more than 270,000 visitors in 2014), with operations run by people from the small town of Mutitjulu. A 16-kilometer (10-mile) road circles the rock, and a disused airstrip lies near the town. Darker greens indicate swaths of vegetation that thrive because of the many natural springs along the footslopes of the rock. Farther away, desert scrub vegetation on the drier soils of the linear sand dunes has browner tones.

Uluru and a similar striking landform known as Kata Tjuta (Mount Olga) are part of the Uluru-Kata Tjuta National Park, created as a UNESCO site in 1994 for cultural preservation and protection. Uluru and Kata Tjuta are remnants of sediments eroded from an ancient mountain range that existed about 550 million years ago. The sediments were subsequently buried and compressed to form harder rocks—called arkose and conglomerate by geologists. These rocks were later tilted from their original horizontal orientation by powerful tectonic forces. Views from above now clearly show the hundreds of originally flat-lying layers that make up Uluru. Softer and younger sedimentary rocks were then eroded away, leaving the more resistant rocks exposed to form the present-day landforms.

Uluru is thought by native peoples to have been created by ancestral beings during the Dreamtime, which has been described as the essence of aboriginal culture and spirituality. The rock is regarded as one of the ancestors’ most impressive pieces of work. Ancient paintings throughout its caves and fissures describe this relationship, keeping Dreamtime traditions alive. The proximity of the Mutitjulu settlement to the rock symbolizes the spiritual connection between the local people and Uluru.

http://go.nasa.gov/2h3R126

The River that Trapped Itself

Black Canyon of the Gunnison National Park owes its name to its deep, dark crevices. The Gunnison River sculpted these walls, cutting thousands of feet into the bedrock. Much of the time, the winding waters at the bottom of the gorge are submerged in shadow.

Even from space, this canyon in Colorado commands attention. The Operational Land Imager (OLI) on the Landsat 8 satellite acquired a natural-color image of the park on September 24, 2013. That image was draped over an ASTER-derived Global Digital Elevation Model to show the area’s topography. At their tallest, the canyon’s near-vertical walls plummet roughly 2,425 feet (740 meters).

The Gunnison River was already cutting into the stone during the Pleistocene era, when melting glaciers strengthened the river’s current. Running hard, the river picked up sand, gravel, and boulders, “efficient tools for canyon-cutting,” according to the Roadside Geology of Colorado. In a process called stream superimposition, the river scoured its way through softer lava and ash, sedimentary rocks and, finally, the hard Precambrian rock below. Today the Gunnison is forced to stay on this beaten path, unable to leave the valley because it is trapped between towering walls of bedrock.

The same geological features that give this landscape jagged edges also test the mettle of hikers who try to climb the inner canyon. For instance, the Warner Route, one of the park’s lengthier trails, spans a vertical drop of roughly 2,700 feet (830 meters)—nearly twice the height of the Empire State Building. The National Park Service website warns: “hikers are expected to find their own way and to be prepared for self-rescue.”

Other visitors come to see the canyon after the Sun sets. The park’s relatively remote location makes it an ideal spot to view stars. In 2015, the Black Canyon became an International Dark Skies Park.

http://go.nasa.gov/2gWrGqO

Bear Lake

This bright blue lake, with its tight swirl of a light-toned sediment, caught the eye of an astronaut on the International Space Station. Situated on the Idaho-Utah border, Bear Lake is one of the bigger lakes in the Rocky Mountains.

The two swirls near the center of the 30 kilometer (19 mile) long lake are rotating in the deepest water—perhaps from outflow from Swan Creek or Fish Haven Creek. North Eden Creek has laid down a little delta at its mouth. Two center-pivot irrigation fields sit on the delta, one of the few flat places in this mountainous landscape.

The more diffuse swirls at the north end of the lake (lower right) likely formed from sediment entering from North Eden Creek. This sediment is carried north along the shoreline by lake currents, joining with sediment eroded from the white beaches.

When the north-end beach formed, it cut off of Bear Lake from the Mud Lake lagoon. Muddy sediments subsequently collected to form a dark-toned, vegetated wetland now protected as the Bear Lake National Wildlife Refuge. A much larger protected area is the Cache National Forest, visible across the entire top part of the image. Dramatic canyons like Fish Haven Canyon cut deeply into the Wasatch Mountains.

http://go.nasa.gov/2hdbaBQ

Smog and Haze in Northern China

Many parts of eastern China were put on orange alert on December 4, 2016, when heavy smog veiled large swaths of the country. The haze stranded passengers at airports in northern China and slowed down city life in Beijing, which reached orange alert level on December 1.

An orange alert signals heavy pollution—a PM2.5 (particulate matter) density of more than 150 micrograms per cubic meter of air—for three consecutive days. Such high concentration of fine particles in the air can cause lung and heart problems for vulnerable individuals, including asthmatics, children, and the elderly.

The Visible Infrared Imaging Radiometer Suite (VIIRS) on the Suomi NPP satellite acquired this natural-color image of northeastern China on December 6. Photos taken from the ground also showed low visibility—less than 200 meters (roughly 650 feet), according to news reports. On December 5, People’s Daily reported smog blanketing more than 60 Chinese cities.

Low winter temperatures exacerbate smog since they cause temperature inversions. Warm air settles atop a layer of cooler, denser, smog-ridden air, trapping it like a lid. High concentrations of smog frequently appear in cities like Beijing during winter.

http://go.nasa.gov/2hjoh16

Where the Organ Pipes Grow

Organ pipes dot the desert floor in southern Arizona. These tall, branch-like formations of cacti lend unusual beauty to Organ Pipe Cactus National Monument, while also sheltering its inhabitants. This federal monument is the only place in the United States with large stands of the organ pipe cactus. They abound on southern-facing slopes, and can live for more than 150 years, according to the National Park Service. The cacti do not produce their first flowers for roughly 35 years.

The Operational Land Imager (OLI) on the Landsat 8 satellite acquired this image of Organ Pipe Cactus National Monument on August 29, 2016. From space, the park appears to be an arid landscape of braided streams and rocky outcroppings. It includes more than 500 square miles (1330 square kilometers) of land—mostly scraggly hills and vegetation.

On the desert floor, small desert animals scamper around the cacti. The park comes alive at night when the kangaroo rat—a critter that resembles a mouse and belongs to the gopher family—scavenges for seeds. Nearby, the javelina (“musk hog”) uses its tusks to sever a prickly pear cactus. Above, lesser-nosed bats feed off the sweet pulp of night-blooming saguaro flowers. Thousands of them fly here from their winter homes in Mexico each year.

In its cowboy years, the monument was a very different place. More than 1,700 cattle roamed the desert hills as recently as the 1960s. The grazing permits were revoked, and the last of the animals left the monument in 1972, according to the National Park Service. Today, old roads still lead to abandoned wells and ranch structures. The wild grasses and small cacti—once trod over by cattle—continue to recover.

http://go.nasa.gov/2h2i4q0

Rare November Snow in Tokyo

On November 24, 2016, Tokyo received its first November snowfall in more than half a century. The Moderate Resolution Imaging Spectroradiometer (MODIS) on NASA’s Terra satellite captured this natural-color image the same day. The snow fell in and around the Japanese capital, coating the metropolitan area and accumulating along some sidewalks.

The second, false-color image from Terra shows a stark contrast between snow (blue) and clouds (white). The snow traces the contours of surrounding mountains and is distinguishable from clouds offshore. Central Tokyo is gray-brown in color, suggesting less accumulation or faster melting. Urban centers tend to shed snow faster than surrounding countryside because they are often hotter, a result of the urban heat island effect.

The November dusting was caused by a cold air mass moving down from the Arctic, according to the Japan Meteorological Agency. Meteorologists connected the storm to the Arctic oscillation, a climate pattern that affects the northern hemisphere. Usually, high air pressure in the mid-latitudes prevents colder, low-pressure air seeping down from the Arctic. However, weaker pressure systems occasionally disrupt this barrier, and colder air can penetrate further south, as in this case.

http://go.nasa.gov/2gSh4J4

Dust Over the Arabian Sea

On December 12, 2016, the Moderate Resolution Imaging Spectroradiometer (MODIS) on NASA’s Aqua satellite captured this natural-color image of dust over the Arabian Sea. The vortex of clouds and dust is rotating in a direction dictated by Earth’s rotation. In the Northern Hemisphere, this cyclonic rotation is counter-clockwise when looking down from space.

The dust arrived over the sea with a mass of warm desert air—a condition known to suppress cloud formation. It is possible that the warm, dry center of the vortex had not mixed much with the moist marine air surrounding it. The edges of the vortex may have mixed more with the marine air, giving rise to shallow, isolated cumulus clouds.

http://go.nasa.gov/2hclGXb

Close Look at a Crack on Larsen C

In late August 2016, sunlight returned to the Antarctic Peninsula and unveiled a rift across the Larsen C Ice Shelf that had grown longer and deeper over the austral winter. Satellites spotted it in natural-color imagery. By November, the arrival of longer days and favorable weather made it possible for scientists to take a closer look.

These photographs show close and wide views of the rift from the vantage point of NASA’s DC-8 research aircraft. NASA scientist John Sonntag snapped the photos on November 10, 2016, during an Operation IceBridge flight. The mission, which makes airborne surveys of changes in polar ice, completed its eighth consecutive Antarctic deployment later that month.

The rift in Larsen C measures about 100 meters (300 feet) wide and cuts about half a kilometer (one-third of a mile) deep—completely through to the bottom of the ice shelf. While the rift is long and growing longer, it does not yet reach across the entire shelf. When that happens, Larsen C will shed an iceberg about the size of Delaware.

Cracks and calving of ice from the front of an ice shelf are normal. Shelves are fed by glaciers and ice streams coming from the interior of the continent. They advance into the ocean until a calving event takes place. The shelf front retreats and then advances again. The whole cycle can occur over the span of a few decades.

But calving that happens faster than a shelf can re-advance can mean trouble for an ice shelf. For example, large and frequent calving events at Larsen B preceded that shelf’s final period of rapid disintegration, which occurred in just six weeks in 2002. Whether Larsen C will respond in a similar way remains to be seen, but that’s one reason why scientists plan to make observations before and after the next calving event.

Ice shelves float, so they do not directly contribute to sea level rise. They are important, however, because they buttress land ice and keep it inland. If a shelf disintegrates, glaciers that feed it can flow more quickly out to sea—a process that directly increases sea level.

http://go.nasa.gov/2gwPqNq

Vardah Takes Aim at India

One week after dropping flooding rains and killing 14 people in southern Thailand, Tropical Cyclone Vardah was poised for landfall along the east coast of India.

On December 11, 2016, the Moderate Resolution Imaging Spectroradiometer (MODIS) on NASA’s Terra satellite acquired a natural-color image of Vardah (above) as it churned in the Bay of Bengal. Around the same time, the U.S. Joint Typhoon Warning Center reported sustained winds of 75 knots (85 miles or 140 kilometers per hour) and gusts up to 90 knot gusts (105 mph or 165 kmph). Significant wave heights (in the open ocean) approached 24 feet (7.3 meters), and the center of the storm was approximately 640 nautical miles (1030 kilometers) south-southwest of Calcutta.

Forecasters expect the slow-moving storm to weaken slightly to tropical-storm force before making landfall on December 12 in the Tamil Nadu and Andhra Pradesh states of India. The storm is expected to drop as much as 10 inches (25 centimeters) of rain in some areas, with the potential for flooding. On the other hand, the rain could bring some much-needed relief to drought-ridden areas, such as the parched city of Chennai.

As early as December 8, regional officials put India’s coastal areas on high alert for severe weather impacts. Schools and colleges in the region were canceled in anticipation of the storm.

http://go.nasa.gov/2he4fID

Fleeting Fog in India

It’s not unusual for low clouds and haze to blanket northern India, just south of the Himalayas. You can see evidence of this in a gallery of satellite images we have accumulated over the years. But on December 7, 2016, the Moderate Resolution Imaging Spectroradiometer (MODIS) on NASA’s Terra satellite captured images of curious structures among the familiar cloud cover.

The first image shows a wide view of the clouds and smog trapped against the Himalayas. For the most part, the clouds appear white, although some areas are obscured with a dull gray haze. The second image shows a detailed view of clouds that appear uniquely mottled. The locations of the “holes” happen to coincide with cities, including India’s capital, New Delhi.

The cause of these features is a mystery. “I would definitely say there is a connection with the cities,” said Steve Lang, a research meteorologist at NASA’s Goddard Space Flight Center. “But without being there, we can only speculate that it could be due to either additional aerosols or urban heat islands, or both, having an effect on the clouds.”

The holes appear similar to hole-punch clouds, which occur when super-cooled liquid clouds are disturbed, usually by the particles in airplane exhaust. The exhaust triggers a cascade of freezing: ice particles bump into liquid drops, and then larger ice particles literally fall out of the sky and leave behind a hole.

But Lang and colleagues checked other lines of evidence—different MODIS channels, local reports, and soundings—and think that these are water clouds (essentially fog). It could be that the fog was burning off faster over the cities, which tend to be warmer than their surroundings.

“Most likely, the urban heat island is added to the effects of the Sun as it burns off the fog,” Lang said. “It could also be that the fog was thinner over the cities to begin with due to the heat island effect.”

http://go.nasa.gov/2htKgCw

Iberá Wetlands in Sunglint

An astronaut flying over central South America was following the Sun’s reflection point (also known as sunglint) as it flashed across the water surfaces of the Iberá Wetlands. Sunglint makes for startling images that appear more like black-and-white photos. The many bright, irregular, elongated patches (especially on the lower right) are bigger lakes, while the smaller, more circular features are hundreds of tiny ponds (upper left). Interestingly, the name Iberá comes from ý berá, the local Guaraní words meaning “bright water.”

South America’s second-largest river, the Paraná, used to flow through this area from top right to lower left. The river built up a great inland delta, leaving the larger lakes in the slightly lower areas of the floodplain. The tiny lakes are situated on older river terraces, which stand 3 to 9 meters higher than the average local elevation. The region is so waterlogged that farming is difficult and is restricted to the higher, drier ground. (See the farm fields near the top right.)

It is unclear why the higher areas have the lakelets, or why they are so round in shape. But one idea is that during very dry times in the last Ice Age, dry winds scoured out numerous hollows, as we see in many deserts today. When the climate grew wetter, these depressions filled with water and marshy vegetation colonized the shorelines. As sediment slowly washed into the lakelets, all angular shoreline shapes became smoothed and rounded. The smallest ponds are almost completely filled with vegetation, except for a halo along the shorelines where open water reflects the Sun. It is unclear why the ponds have developed this interesting vegetation pattern.

http://go.nasa.gov/2h6R6Oe

A Dry Start to South America’s Wet Season

Even before the 2016 dry season started in South America, a marked deficit in rainfall was apparent across much of the continent. Parts of the Amazon, for example, were already far drier than in 2005 and 2010, the last serious drought years. Now, as the wet season approaches, intense drought still runs deep across the Amazon basin and much of Brazil.

This map shows the accumulated deficit in rainfall flowing into surface and groundwater storage as of October 2016. The data were compiled by the Global Precipitation Climatology Centre, which analyzes precipitation data collected from rain gauges. Red areas show the level of the rainfall deficit compared to the norm for October, while blue areas had more than usual amounts of rainfall.

Some areas fared better than others. For example, Brazil’s largest city, São Paulo, is located between areas that were anomalously dry (to the north) and others that were anomalously wet (south). The city has reportedly received sufficient rain since late 2015 to begin raising the water level in its main reservoir system.

But as the map also shows, rainfall elsewhere in Brazil and the Amazon was far below normal for October. It remains to be seen whether the rainfall associated with the wet season can break the ongoing drought.

“In Brazil, the rainy season is the austral summer, from December to March,” said Augusto Getirana, a hydrologist and remote sensing scientist at NASA’s Goddard Space Flight Center. “It’s hard to tell if this summer will be the same, but considering the pattern of previous years, my guess would be a yes.”

Getirana knows well the patters of recent years. In February 2016, he published a satellite-based study showing that southeastern Brazil lost 6.1 centimeters of water per year from 2012 to 2015. That may not sound like much, but in terms of volume over the entire area, that’s 56 trillion liters of water.

http://go.nasa.gov/2gq3ufb