London at night, snow in the Sahara and Hawaiis volcanoes are among the images captured by European Space Agency and Nasa satellites last month
A night-time view of western Europe captured by crew members aboard the International Space Station. London is visible in the centre of the image, photographed from more than 250 miles above.
The northern part of western Australia close to the edge of the Great Sandy Desert presents a landscape of desert plains and grasslands. At the centre of the image is the Wolfe Creek Crater, the remnant of a meteorite crash some 300,000 years ago. The crater measures about 875 metres across and plants grow at its centre, likely thriving off water reserves from seasonal rain. The name for the crater comes from the nearby Wolfe Creek, after being spotted during aerial surveys in the 1940s. But the crater has long been known to Aboriginal people as Kandimalal and is believed to be the site where a rainbow-coloured snake emerged from the ground to create Wolfe Creek. Mystical reptiles aside, the park is home to the brown ring-tailed dragon a type of lizard. While roads appear as straight lines cutting across the landscape, some other lines appear brighter, particularly in the lower central part of the image. These are sand ridges shaped by east-west prevailing winds; their brightness comes from a difference in vegetation, or lack of vegetation.
Snow on the edge of the Sahara desert is rarebut on 19 December snow fell on the Algerian town of An Sfra, sometimes referred to as the gateway to the desert. The town of about 35,000 people sits between the Atlas mountains and the northern edge of the Sahara. The last recorded snowfall in An Sfra occurred in February 1979. The scene shows an area near the border of Morocco and Algeria, south of the city of Bouarfa and southwest of An Sfra.
Sand spills from a newly dredged channel in this view of Vietnamese-held Ladd Reef, in the Spratly Island group in the South China Sea. An outpost that houses a Vietnamese garrison can be seen on the central northern part of the reef, accessed by two small perpendicular channels.
Officials issued pollution alerts for more than 40 cities in northern China in mid-December 2016. During its latest bout of intense smog, which led to red alerts in more than 20 cities, authorities shut down schools and airports and told citizens to stay indoors.
Smog was particularly bad in cities like Beijing, which declared a five-day pollution red alert. The Chinese capital reached dangerous levels of more than 400 micrograms per cubic metre. In Shijiazhuang, the capital of Hebei province, airborne pollutants surpassed World Health Organisation (WHO) guidelines by 100 times on 19 December.
From space, the smog appears grey in this view of north-eastern China. Heavy smog shrouds parts of the country, while the brightest, whiter areas are likely clouds or fog.
While smog regularly occurs in China, the extent of this event stands out and is comparable to a record-breaking air pollution event in January 2013, when ground-based sensors at the US embassy in Beijing reported PM2.5 measurements of 291 micrograms per cubic metre of air.
Low winter temperatures often cause dense, smog-laden air to be trapped low in the atmosphere. According to Andrew Sayer, an atmospheric scientist working for Universities Space Research Association at Nasas Goddard Space Flight Center, there are some indications that such incidents have been happening more frequently in the past few decades, though the reason for the increase has yet to be determined. People are trying to figure out whether its due to changing air patterns, he said, or whether theres more stuff in the air that stagnates.
The Strait of Gibraltar is a narrow waterway that separates Spain from Morocco, Europe from Africa, and which exchanges water between the Atlantic Ocean and the Mediterranean Sea. The narrowest point is only 8.9 miles (14.3 km) wide, while the waters are about 980 metres (2,950 feet) deep. Spain sits in the north, Morocco in the south, the Atlantic Ocean in the west and the Mediterranean Sea in the east. Sediment discolours the waters of the Atlantic off the coastlines of both continents. Grey pixels mark the locations of human habitation, most notable are Tangiers, on the western tip of the Strait in Morocco and the group of cities surrounding the Bay of Gibraltar on the east of the Spanish side of the strait.
Expansion at the port of Rotterdam has changed the shape of the coastline of the Netherlands while increasing the cargo capacity at Europes largest port. This pair of Landsat images spanning 15 years shows the development of the Maasvlakte 2 project. The port provides accessibility for the transportation of cargo from Rotterdam to the rest of Europe. Land building at Maasvlakte 2 began in 2008. About 230m cubic metres of sand were dredged from the North Sea to create about 5,000 acres of new land. In addition, 7m metric tonnes of stone were used to construct new seawalls.
Commercial cargo operations at the new Maasvlakte 2 facility began in December 2014. Its terminals currently can hold 2.7m individual 20-foot shipping containers. There is more space for terminals to be built on the new land once demand increases, which would increase the ports cargo handling capacity further. The expansion of land resulted in some loss of permanently flooded sandbanks that affected the availability of food for some protected bird species, such as the common scoter, the sandwich tern, and the common tern. However, this loss was compensated for by establishing a protected seabed area south of the Maasvlakte 2 in the Voordelta. Also, three bird-resting areas in the seabed were established where boat traffic is restricted. Landsat can help monitor this coast to ensure the positive impact of these protected areas as compensation for the land expansion.
This image captures the reflection of the full moon on the fresh snow around the US Great Lakes, using day/night band that can detect faint light sources. An Arctic air mass brought more snow to communities around the Great Lakes on 14 December, on top of an earlier accumulation that piled up to several feet in some areas. The crisp, bright glow of city lights in Chicago and Detroit offers further evidence that the ground is covered in snow. If the white shade in the image were due to cloud cover, an overcast sky would likely obscure lights on the ground. Note how clouds blur the landscape in the bottom left part of the image. Cloud streets appear above lake Huron and lake Superior. These parallel rows of clouds are created by cold, dry air blowing over a lake and accumulating water vapour.
A natural-colour image of dust over the Arabian Sea. The vortex of clouds and dust rotates in a direction dictated by the Earths 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 centre 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.
A large dust cloud hangs over the Atlantic along the north-western coast of Africa in this colour-enhanced image. The bright colours shown here are the result of dust enhancement an experimental data product created by scientists at the European Organisation for the Exploitation of Meteorological Satellites (Eumetstat). Based on infrared channel data, this RGB (red-green-blue) enhancement was created to help analysts monitor the evolution of dust storms. According to Eumetstat, monitoring dust in the atmosphere 24 hours a day can be a challenge because the appearance of dust in satellite imagery changes drastically from day to night. The orange-brown colour is atmospheric moisture. Dust appears as magenta or pink. Reds mark thick cirrus clouds; dark blues are thin cirrus clouds; and the other shades of blue indicate the surface (land and water) of the Earth. The bright yellow is the hot surface of the Sahara.
Krasne Lake, Crimea. These hypersaline lakes in northern Crimea are home to a variety of algae and other micro-organisms that are the root cause of the lakes vibrant, otherworldly colours.
The western area of Spains province of Seville and its capital with the same name, showing its location on the Guadalquivir river. While the original course of the river is visible snaking through the city on the right, we can see where water has also been redirected in a straighter course on the left. The fertile valley of the Guadalquivir is evident by the plethora of agricultural structures, particularly noticeable in the upper right. The Sierra Morena mountain range runs north of the Guadalquivir basin, and we can see the foothills in the upper left corner.
In the upper-central section of the image an open-pit copper mine, appears white. This type of mining is often practised when deposits of minerals or rocks are found near the surface. To the west of this mine are two other open-pit mines filled with water. South of these water-filled mines are two circular structures reminiscent of clamshells. These are large solar power plants.
In the mid-1980s, Saudi Arabia embarked on an ambitious agricultural plan to grow crops in its desert areas using ancient fossil water deep beneath the sand. Centre-pivot irrigation systems were installed in the barren Wadi As-Sirhan basin in the north-west of the country. The water, once used to grow fruit, vegetables and wheat, was buried deep underground for thousands of years.
These Landsat images show the remarkable transformation of desert sand in 1986 into green, circular fields some as large as 1km across by 2016.
The drawback with centre-pivot irrigation lies in the fact that water in these aquifers is not recharged. Rainfall here only averages 100mm to 200mm per year, making groundwater in the area a non-renewable resource. Hydrologists predict it will only be feasible to pump the groundwater for another 50 years, so domestic wheat production will be phased out. Local farmers are being encouraged to engage in alternative sustainable agricultural activities, such as greenhouse farming using advance drip irrigation techniques to produce fruits and vegetables.
When the real estate developer Del Webb conceived Sun City in the 1950s, the goal to build a retirement community specifically for adults was unheard of at that time. It was fitting, then, that the layout of the community be equally distinctive. Amid the rectangular grids that make up most neighbourhoods in the greater Phoenix area, Sun Citys radial streets, curving lines of homes, and verdant golf courses are hard to miss when seen from above. At the centre of the circular neighbourhoods are community buildings: mainly churches, with a few stores and health-care facilities mixed in. Pools, tennis courts, pickle ball courts, and bowling alleys are squeezed in between the many single-level homes that dominate Sun City.
The retirement community concept proved wildly successful when Sun City was unveiled in 1960 with just five model homes, a recreation centre, one golf course, and one shopping centre. The opening weekend drew more than 100,000 people and inspired a cover story in Time. Decades later, the age-restricted community has seven pools, eight golf courses, and some 40,000 residents. Sun City proved so successful that several more retirement communities were built just to the west. A few of them include golf courses with distinctive layouts reminiscent of flowers when viewed from above.
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