On 26 May Wolf Volcano on Isabela Island in the Galapagos Islands erupted for the first time in 33 years. Lava flows from the summit were accompanied by ash and smoke rising 6 miles into the air. The lava flows are highlighted in red. The image covers an area of 18.4 by 29 miles.
The first two named storms of the eastern Pacific Ocean hurricane season are spinning off the west coast of Mexico. Hurricane Andres is winding down and expected to drop to depression-strength and turn east in the next couple of days. Tropical storm Blanca is expected to become a major hurricane as it heads north-northwest towards Baja California. Although Blanca’s strength will diminish somewhat before landfall, it may still be at hurricane strength and produce swells that bring life-threatening surf and rip current conditions to the coast of southwestern Mexico.
Astronauts aboard the International Space Station used a high magnification lens to capture the details of the Aswan high dam on the River Nile in southern Egypt. This vast engineering project was started in 1960 and completed in 1970, and it is one of the largest earthen embankment dams in the world at 3,830 meters (12,565 feet) long and nearly 1,000 meters (3,281 feet) wide. The dam holds back 132 cubic km of water in Lake Nasser. Hydropower generated at the dam wall provides 2.1 gigawatts—half of Egypt’s needs in 1970—giving numerous villages access to electricity for the first time. The dam virtually eliminated the danger of floods downstream in the Nile valley, which has had both positive and negative effects downstream.
In August 2009, construction began on China’s first large-scale solar power station. Six years later, solar panels have expanded much deeper into the Gobi Desert, where sunlight and land are abundant. The solar farms, located on the outskirts of Dunhuang in northwestern China’s Gansu province cover about three times the area since 2012. Gansu’s total installed solar capacity in 2014 reached 5.2GW, and the government had set the goal of increasing the province’s capacity by an additional 0.5GW in 2015.
Smoke from agricultural fires (shown with red outlines) rises up in Huaibei, in the North China Plain, a fertile and densely-populated region. It produces 35% of the country’s agricultural yields. The staple crops are wheat and maize. Winter wheat is sown in mid-October and harvested at the end of May. In June, farmers burn the remaining plant residue to fertilise the soil for the maize crop. Three quarters of all fires in the North China Plain occur in June.
A phytoplankton bloom in the Sea of Marmara. Situated between the Black Sea and the Aegean Sea, it is full of a rich soup of nutrients and life The Marmara has an unusual layered structure with fresher water near the surface and much saltier water near the bottom. That fresh surface is fed by exchanges with the Black Sea and by flows from the Susurluk, Biga, and Gonen Rivers. The fresh water makes it easier for floating, plant-like organisms—phytoplankton—to grow, as does the abundance of nutrients pouring into the seas from European and Turkish rivers. The sea is surrounded on all sides by Turkey. The swirling shapes on the water are phytoplankton, with the yellow-green and red-purple filaments likely (but not necessarily) representing different species.
In early June a strong low pressure system over the North Atlantic Ocean brought rain and gusty winds to Ireland and the United Kingdom as this true-colour image of the spiralling system shows on 5 June. A very deep low pressure area lies in the centre of the spiral, just off the northwestern shore of emerald-green Ireland. Bands of cloud, containing rain and thunderstorms, swirl into the centre of the low, and extend over the British Isles.
The Great Barrier Reef is the world’s largest coral reef system, covering more than 344,000 sqkm. The reef’s diversity of life faces numerous threats such as climate change, pollution, fishing and outbreaks of the coral-preying crown-of-thorns starfish. From their vantage point some 800 km high, satellites offer the means to monitor the health of reefs across the globe, as well as other parameters that indicate the overall health of oceans. Optical satellite imagery, like what we see here, can be used to monitor the ocean colour and detect harmful phytoplankton blooms. They can also help map the ocean floor at shallow depths.
Seen from space, few other dormant volcanoes look as exotic and spectacular as Waw an Namus. The volcano, located deep in the Sahara desert in the Fezzan region of southwestern Libya, appears as a smear of dark basaltic ash and tephra that contrasts sharply with the light-coloured sand of the Sahara. While the precise date of the most recent eruption is not known, the lack of erosion and weathering implies that it probably occurred in the last few thousand years. South of the ash field, mud streams have begun the slow process of eroding the tephra and ash away. The ash field extends around a much smaller caldera that is about two-miles wide. Calderas are hollowed-out circular depressions that form at the summit of volcanoes when magma is withdrawn or erupted from a shallow underground magma reservoir.
This is Italy’s Po valley, about 24 miles east of Milan. A highway runs across the image, while the Serio river is visible running north to south in the middle. The above is a subset of the first image taken by Europe’s Sentinel-2A satellite, offering a glimpse of the ‘colour vision’ that it will provide for the Copernicus environmental monitoring programme. While northern and central Europe were mostly cloudy, Italy’s typical sunny weather allowed the teams to get their first glimpse of the multispectral instrument’s capabilities over the northwestern part of the country and the French Riviera – and they were excited by what they saw: buildings in Milan, agricultural plots along the Po River, and ports along the southern French coast.
The brightly coloured Laguna Colorada in the Bolivian Andes Mountains. The lack of atmospheric haze at high altitude—the lake sits 4,300 meters above sea level —helps make images of the region especially clear. The strong red-brown color of this shallow, six-mile long lake is derived from algae that thrive in its salty water. Occasionally the lake has green phases as well because different algae display different colours. The type of algae at any given time is determined by the changing salinity and temperature of the water. Laguna Colorada is a wildlife reserve, listed in 1990 as a ’Ramsar wetland of international importance.’ The lake is home to vast numbers of flamingos. Snow-capped volcanoes appear at the top center and lower left. Access roads on three sides of the lake are used by tourists to visit these other-worldly landscapes.
An interferogram created by combining two Sentinel-1A radar scenes over the Danube Delta in Romania.
Wildfires burning in Alberta, north of the Athabasa oil sands, are outlined in red, while forests appear dark green. A combination of lightning, parched forests, and strong winds have fuelled the fires. According to the Canadian government, 27 uncontrolled fires were burning in Alberta on 28 June. The 2015 fire season got off to an unusually early start in Canada when blazes broke out in the Northwest Territories, British Columbia, and Alberta in late May.
This Earth observation of Iran was taken by members of Expedition 44 on the International Space Station on 20 June. Described as ‘Earth Art’ it is the western shore of Lake Urmia near Gülmanxana, Iran.
The city of San Francisco is on a peninsula in the centre left section of the image. In the upper-central portion, we can see the delta of the Sacramento and San Joaquin rivers with brown, sediment-filled water flowing down into the larger bay. Starting in the top-left corner of the image and running diagonally to the south is the San Andreas Fault. This is the border between the North American and the Pacific tectonic plates, and is responsible for the high earthquake risk in the area.
A new study shows that Beijing’s physical infrastructure quadrupled between 2000 and 2009 and that the new buildings and roads themselves—not including pollution created by new inhabitants and their vehicles—increased winter temperatures by about 3 to 4C and reduced wind speed by about 2 to 7 miles per hour, making the air more stagnant. Grey and black indicate buildings, with the tallest and largest buildings in the city’s commercial core appearing lighter grey. Other colours show changes in areas not yet urbanised. Blue-green indicates the least change, yellow-orange more change and red the greatest change.
Researchers recently completed an intensive study of levees and wetlands along the Louisiana coast, making measurements with three advanced imaging instruments mounted on a Nasa research aircraft. Nasa makes several aerial survey flights over the Gulf Coast each year in order to keep consistent records of ground subsidence—the gradual sinking of a patch of land—which can compromise the integrity of roads, buildings, and levee systems. Scientists also closely monitor vegetation changes in the coastal wetlands. The above radar image shows Wax Lake delta in Louisiana, one of the few places in the world where deltas are growing naturally. Note how the channels through the land appear to extend underwater, beyond the islands and lobes that stand above the water line. The colours represent the polarisation of the radar waves (the direction of the electric field in the waves) as they are transmitted and reflected off of the landscape. Researchers look for changes in those reflections in order to figure out where land has shifted or has been disturbed by human activity.
Spain’s Cádiz Bay was photographed by a microlight pilot on 29 January 2009 during research on coastal vegetation by the University of Cadiz. ‘The intricate network of channels and creeks contrasts with the regular shapes of transformed saltmarsh [right of picture],’ writes Edward P Morris, who submitted the photo to the Sentinel-2 ‘Colour vision’ photo competition. ‘Transformation for salt production began with the Romans, but in recent years has declined. Once up-keep of seawalls stops, nature begins to shape the marsh again (lower right).’ This photo received an honourable mention in the competition.
