From space, the strait of Gibraltar appears tiny compared to the continents it separates. At the strait’s narrowest point, Africa stands just 14km (nine miles) from Europe. But the narrow waterway is a complex environment that gives rise to striking phytoplankton blooms when conditions are right. The intricate swirls of phytoplankton trace the patterns of water flow, which in this region can become quite turbulent. For example, water moving east from the North Atlantic into the Mediterranean has created turbulence in the form of internal waves. These waves – sometimes with heights up to 100 metres – occur primarily deep within the ocean, with just a mere crest poking through the surface. At the same time, water flowing west helps stir up water in the North Atlantic, including the Gulf of Cádiz. While most of the swirls of colour are phytoplankton, the ocean scientist Norman Kuring of Nasa’s Goddard Space Flight Center notes that some of the colour near coastal areas could be due to sediment suspended in the water, particularly near the mouths of rivers.
Vojvodina in northern Serbia lies in the southern part of a region once covered by the Pannonian sea some 2–23m years ago. Today, the land boasts a fertile soil – hence the plethora of agricultural fields visible as geometric shapes, reminiscent of cubist artwork.
The Tisza river snakes down from the north. Curved, brushstroke-like light green areas primarily along the east side of the river reveal its former course. Some of these areas are now used for agriculture, while others may still be too wet.
Man-made waterways appear as straight black lines – likely for draining the swamps, transportation and irrigation. Nestled among the fields, there are a number of small towns with grid layouts. This type of city planning was invented by ancient Greece’s Hippodamus – known as the “father of European urban planning”.
The image is in false colour, with different colours indicating varying vegetative states. Yellowish patches indicate soil or freshly ploughed land, while shades of blue indicate either the same crop or different crops at a similar stage of growth.
Sentinel-2’s 13 spectral bands can provide images that can distinguish between different crop types as well as data on numerous plant features, such as active chlorophyll content and leaf water content, all of which can monitor plant growth.
This kind of information helps inform decisions about how much water or fertiliser is needed for a maximum harvest or for forming strategies to address climate change. While this has obvious economic benefits, this is also important for developing countries where food security is an issue.
Kazakhstan has roughly 3% of the world’s crude oil reserves. With proven reserves of 30bn barrels, the large, landlocked country has the second most in Eurasia and the 12th most in the world. The oil is spread between 172 oil fields, mainly in the western part of the country. This image of Karazhanbas oilfield in the Mangystau Province shows a blanket of snow covering the oilfield, making the drilling wells, pipelines, roads, and other infrastructure stand out as if in 3D. With 230m barrels in reserves, Karazhanbas is not Kazakhstan’s largest oilfield. The nearby offshore Kashagan field is thought to hold between 7bn and 13bn barrels of recoverable crude oil. The Tengiz field, located near the shores of the Caspian sea, has reserves between 6bn and 9bn barrels. Since Kazakhstan is landlocked, it relies on pipelines to distribute its oil. The Karazhanbas field is located near the Uzen-Atyrau-Samara pipeline, which conveys oil north and east toward Russia.
“Europe by night, under clear skies is a carpet of lights!” posted the ESA astronaut Thomas Pesquet on social media. Pesquet’s Proxima mission is the ninth long-duration mission for an ESA astronaut, and is named after the closest star to the sun, continuing a tradition of naming missions with French astronauts after stars and constellations. The mission is part of ESA’s vision to use Earth-orbiting spacecraft as a place to live and work for the benefit of European society, while using the experience to prepare for future voyages of exploration further into the solar system.
On the ground, individual petals pop with vivid color. From space, whole acres of flowers brighten fields in the southern Netherlands. Each year towards the end of April, scores of people arrive from Amsterdam to visit this flower-filled landscape and see the famous tulips and other spring blooms, including crocuses, hyacinths, and daffodils. Entire fields of bright reds and yellows stand out against the surrounding brown and green terrain. (The blue square is the roof of a nearby factory building.) The flowers bloom for several weeks, peaking in late April.
Cloud streets – long, parallel bands of cumulus clouds – stretch from roughly north to south over the Greenland, Norwegian, and Barents Seas. Greenland sits in the northwestern section of the image and Norway, Sweden, and Finland sit in the south. Cloud streets are formed when cold air blows over relatively warmer waters. To transport the heat away from the sea surface, columns of heated air called thermals naturally rise through the atmosphere. The air masses rise until they hit a warmer air layer (temperature inversion), which acts like a lid. The rising thermals roll over when they hit this ‘lid’, and loop back on themselves, creating parallel cylinders of rotating air. On the upper edge of these cylinders of rising air, clouds form. Along the downward (descending air), skies are clear.
In the high plains of the Andes in Bolivia, Lake Poopo has virtually vanished. Once covering over 3,000 sq km, and an important resource for lakeside fishing communities, the lake essentially dried up in 2015. What led to Lake Poopo’s demise? Water diversions upstream, weather extremes and recurrent droughts are thought to be to blame.
Central-eastern Brazil – where the Bahia, Tocantins and Goiás states meet. The image shows a large, flat plateau flanked with fields benefiting from rich soils and an apparent abundance of water, before falling off into a green, hilly valley (left). The straight lines in the image are roads, such as the highway running in a nearly straight line from the centre-top to bottom of the image. The area is particularly known for soybean production. The country’s soybean output has increased by more than 3,000% since the 1970s, and Brazil is the second largest global producer of soybeans after the US. Other crops in this area include corn, coffee and cotton. A distinctive feature in this image is the circles – mainly at the centre. These shapes were created by a central-pivot irrigation system, where a long water pipe rotates around a well at the centre of each plot.
In the spring and summer of 2016, scientists recorded the first ever observed case of ‘river piracy’, in Canada’s Yukon territory. The receding Kaskawulsh glacier spurred the Kaskawulsh river to hijack the Slims River, stealing much of its supply of water and dramatically reshaping the region’s drainage.
For years, meltwater from the Kaskawulsh glacier has fed two large lakes at the glacier front; those lakes feed the Slims and Kaskawulsh rivers. Previously, most of the water flowed northward via the Slims river and ultimately emptied into the Bering Sea. A lesser amount flowed southward via the Kaskawulsh to the North Pacific Ocean. But in spring roles reversed and the Slims river began to run low while the Kaskawulsh flooded.
In these false-color images water (dark blue) stands out from the surrounding landscape. Vegetation is green, and snow and ice are light blue. The first image was acquired on 23 June 2015, when the Slims filled its valley. The second image was acquired on 18 June 2016, by which time the Slims river was just a narrow ribbon of water. Meltwater from the thinning, retreating glacier carved a new channel at the front of the glacier (just a few pixels wide in this image) that now connects a series of azure lakes and routes most of the meltwater into the large lake feeding the Kaskawulsh River. As a result, the Kaskawulsh appears much wider. The change, researchers say, is likely permanent, and could affect the local ecosystem.
Russia’s Ulbanskiy Bay area is mostly uninhabited by humans, but it does support sizable numbers of whales, whose cast-off skins have been spotted in these Siberian waters by scientists. In summertime, this bay becomes a feeding ground for bowhead whales, as well as belugas and orcas. Beluga whales come to Ulbanskiy for the seafood buffet; they hunt by driving fish like herring and smelt toward the coast and into freshwater inlets. Some whales begin to enter Ulbanskiy Bay as early as May, when the winter fast ice begins to break up. Their numbers swell in late July, and aerial surveys have observed upwards of 1,200 of them here in August, when food is plentiful. With the arrival of fall, new ice forms in the bay, and the whales head out to open waters. Despite this abundant underwater activity, the bay’s waters appear serene from space. A lighter green band on the left side of the image indicates deciduous (leaf-shedding) trees that have begun to turn color. The marshes around the bay are dotted with small bodies of water—likely thermokarst lakes.
The islands of Great Britain and Ireland turn green with the warmer days of spring. The green mantle of Ireland is not yet as brilliant as the late-spring and summer colors that give rise to the nickname “the Emerald Isle” but it already wears a darker green in many areas than Great Britain. Ireland lies west of Great Britain, and they are separated by the Irish Sea. Swirls of sediment color the Irish Sea. Sediment also colors the waters around much of Great Britain.
The state of South Australia contains some of the driest, most spectacular, and amazingly rugged areas of the country, as well as, in the far south, milder climates and greener land along the coastlines. This stunning true-color image of the region shows the rich red arid soils of the Outback, while brown-and-tan folds mark the craggy mountains and gorges of the Flinders Ranges – an ancient spiritual site made famous by Aboriginal rock art and dramatically roughhewn topography. The most dramatic features captured in this image, however, are several of the famous dry salt lakes of the region. In the north is Lake Eyre, which is sometimes called the “heart of South Australia” due to the roughly (albeit upside-down) valentine-shape. The long Lake Torrens lies to the south, forming a thick backward crescent in the red landscape. Several smaller lakes lie to the west of Lake Torrens and the largest, somewhat amoeboid-shaped lake is known as Island Lagoon. The large lake to the east of the Flinders Range is Lake Frome.
Brown hills speckle the eastern part of Australia’s Lake MacKay. Located on the border of the states of Western Australia and Northern Territory, the salt lake only sees water after seasonal rainfall – if at all. It is classified as an ephemeral lake, meaning it exists only after precipitation. This is not the same as a seasonal lake, which sees water for longer periods. About half of Australia’s rivers drain inland and often end in ephemeral salt lakes. The greens and blues in this image show desert vegetation or algae, soil moisture and minerals – mainly salt. On some of the brown ‘islands’ and on the shore in the lower right, we can see the east–west sand ridges forming lines in the landscape. The lake lies at the edge of the Great Sandy Desert, which covers nearly 285 000 sq km. Roads are scarce in the area, and often frequented by four-wheel drive adventurers.
Agriculture on the Ethiopian Plateau: taken at the end of the dry season, the photograph shows fallow, rain-fed fields (brown and tan) – except around the margins, where forested villages have access to river water. The largest village in the scene is Sciovele. Thin river channels run through long floodplains that arc around the fields. These floodplains are part of a wide, low-lying wetland system that supports both swamp vegetation and another set of fields where crops thrive through the dry season. Farmers in the lower wetlands take advantage of flood-recession agriculture, where wet-season rainwater drains more slowly and is available for plant growth even in the middle of the dry season. The Gilgel Abbay river is lined with very narrow fields that give the greatest number of farmers access to the water. Forests occupy parts of the wetlands; they also stand on a few patches of higher ground, such as the hill in the center of the image and five small circular patches dispersed among the fields. Some of these forests surround monasteries that are characteristic of the region. The relatively high rainfall in the Ethiopian Highlands makes the region suitable for growing coffee, oilseeds, and grains (especially subsistence crops such as wheat and sorghum). However, a recent years-long drought is threatening Ethiopia’s food supply. The US and the Ethiopian governments are planning aid for as many as 10 million people who could face food shortages.
The Bering Sea, north of the Alaska Peninsula. Seasonal sea ice dominates the upper part of the image. Ice plays an important role in the sea’s ecosystem. Growing algae attach to the bottom of the ice; when the ice melts in the spring, it leaves behind a layer of nutrient-rich freshwater on which the algae thrive. Organisms higher up the food chain then eat the algae. In the top-right corner, we can see part of Alaska’s mainland blanketed with snow, as well as Nunivak Island appearing like a massive piece of floating ice. At the centre of the image are the islands of Saint Paul and Saint George – part of the Pribilof Islands. An estimated two million seabirds nest on these islands annually. The swirling clouds on the right side of the image are the result of a meteorological phenomenon known as a von Kármán vortex street.
The ice atop Greenland is not static. It slowly flows toward the coast and enters the ocean via outlet glaciers that ring the giant island. Petermann Glacier, pictured here, is one such “river” of ice. Like most glaciers that come in contact with the sea, Petermann has been known to periodically shed, or calve, icebergs. A new crack on the glacier, visible here, has glaciologists watching Greenland’s northwest coast closely.
“Rifting and calving are normal,” said Kelly Brunt, a glaciologist at Nasa’s Goddard Space Flight Center. “However, if this new rift crosses Petermann and calves a good chunk of ice, it would be the third such relatively large iceberg from this system in about seven years.”
It remains to be seen whether that will happen. Glaciologists are interested in Petermann because two massive bergs that calved from the glacier since 2010 “represent a change to the system,” Brunt said. “While calving is generally a normal process, we are concerned about Petermann because the new calving face is much farther upstream than before 2010.”
Clouds part over southern Patagonia allowing satellites to capture this nearly cloud-free landscape. Southern Patagonia is a remote, sparsely populated region at the tip of South America. The country of Chile lies along the Pacific (western) coast while Argentina sits along the Atlantic Ocean. The borderline between the two countries lies in the Andes mountains throughout most of southern Patagonia. The mountain’s ice fields provide the most spectacular feature of this image, along with the turquoise glacial lakes in the north. Glacial sediment suspended in the waters of these lakes gives them a turquoise color when viewed from space.
A natural-color image of fire and smoke in south and south-east Asia. The red outlines are areas where the satellite detected heat signatures indicative of active burning. Many fires in this region are set intentionally for agriculture and land clearing purposes.
A five-year drought in California ended spectacularly this winter, with the state emerging from one of its driest periods on record by enduring one of its wettest. Reservoirs, lakes, and mountainsides are now brimming with water and snow, though scientists caution that underground aquifers are a long way from having the same bounty that is visible above ground. These two satellite images show key reservoirs in California near their lowest and highest points over the past three years. On 29 April 2015, Trinity stood at 59% of its historical average level for that date; by April 2, 2017, it stood at 114%. As of 19 April, the lake was filled to 95% of its 2.45 million acre-foot capacity. “Reservoirs at the surface are only a partial measure of California’s water health,” cautioned Bill Patzert, a climatologist at Nasa’s Jet Propulsion Laboratory. “From space, it looks like we are out of five years of punishing drought. But the depleted aquifers, 100 million dead trees, and $1bn in flood damage will take decades to deal with.” Scientists at JPL are leading Nasa-wide efforts to better study water storage and precipitation, alongside research partners in the California government and academic research community.
A large plume of dust from the Sahara drifts off the African coast and out into the Atlantic in this true-color image. Although we can see dust in the atmosphere thanks to images such as this, just how much dust enters the atmosphere each year is unclear. Projections range from 200 to 5,000 teragrams a year (one teragram, Tg, equals one trillion grams). Scientists estimate that, on average, about 20 Tg of dust are suspended in the atmosphere at any given time, but the exact amount can vary depending on seasonal variability.
The churning waters off Norway’s coast have been rumored to swallow boats whole. Their force captured the imagination of writers such as Edgar Allan Poe. “Even while I gazed, this current acquired a monstrous velocity. Each moment added to its speed – to its headlong impetuosity,” wrote Poe in the short story “A Descent Into the Maelstrom,” which introduced the word into the English language. “In five minutes the whole sea, as far as Vurrgh, was lashed into ungovernable fury.” Poe went on to describe giant vortices, the likes of which he had never seen in person, but read about in legends. In reality, the maelstrom is not one massive whirlpool, but a series of smaller eddies created by changing tides. The term for these currents, “maelstrom,” derives from the Dutch, “maalen” (to grind, whirl) and “stroom” (stream). In Norwegian, they are called “moskstraumen” or “moskenstraumen” because they are particularly strong off the island of Mosken, reaching speeds of five meters per second (11 miles per hour). The image shows the moskenstraumen as it swirls around the tip of the Lofoten archipelago.
