Satellite eye on Earth: October – in pictures
Peak autumn leaf colour in northcentral Maine, New England, US. The familiar reds and golds typically appear earliest on deciduous trees and shrubs at higher latitudes and elevations, such as here in the mountains of Baxter state park, and take a few weeks before they reach foliage at the coast.
The crescent-shaped barchan dunes of Lagoa dos Barros on southern Brazil’s Atlantic coast. The lagoons formed around 400,000 years ago as part of the cyclic rise and fall of sea level and are known to geologists as the transgression-regression cycle. The crescent shapes are sculpted by strong winds blowing in from the western Atlantic, creating large dune fields that act as barriers against storms and coastal erosion.
Ginseng farms among brown hills and farmland in Heilongjiang province in north-eastern China. The purple and yellow shade covers are used to protect the plants from direct sunlight. China is the world’s leading producer of ginseng. The plant is cultivated for its supposed curative properties, meaning wild ginseng is now scarce across much of Asia.
As Australia comes to the end of one of its warmest and driest winters on record, the effects of heat and drought on this region of New South Wales are visible from space. September also brought unseasonably warm temperatures for the early spring. Compare the browning of the landscape in the second image – taken in September this year – to the same landscape in the first image, acquired a year ago.
The border between Turkey and Syria is easily visible from space, with the green fields of the former giving way to dusty fields in war-torn Syria.
Hurricane Ophelia the day before it hit the west coast of Ireland and England on 15 October. Although weakened into a post-tropical cyclone at this stage, the storm was still powerful enough to cause widespread damage. The highest wind gust was reported at 119 mph (192 kmh) off the coast of Cork at Fastnet Rock, beating the previous record for Ireland, which was 113 mph when the island was battered by hurricane Debbie in 1961.
The once mythical and remote city of Timbuktu at the edge of the Sahara desert and the Sahel, is not easy to reach even in modern times. Flights in and out are scarce, and boats can only travel up the Niger river when water levels are high. The red roads – that contrast sharply here with the lighter sands of the desert – may be the most reliable way to reach the city. The roads are likely made of laterite, an iron- and aluminium-rich soil and rock type common in southern Mali that turns red after exposure to air and water. “Laterite is one of the least soluble materials known to man and so is left behind after millions of years of leaching of the soils by rainfall,” explained Earle Williams, an earth scientist at the Massachusetts Institute of Technology.
On the south-western border of Brunei with the Malaysian state of Sarawak, the different land use is strikingly apparent. On the Malaysian side, a web of small roads indicates intensive land use: in this case clearing of the forest for palm oil plantations. On the Brunei side, the virgin forest is preserved, with few if any roads.
Washington DC’s famous National Mall is visible here from space, with the Capitol Building at its eastern end and the Lincoln Memorial at its west. The White House sits just north of the Mall. Rock Creek Park is the dark green area in the upper-central part of the image, following the flow of Rock creek, a tributary to the larger Potomac river. The large, green area in the upper right is part of the Patuxent research refuge in Maryland, with the Nasa Goddard Space Flight Center located nearby.
Before and after satellite images of Theewaterskloof reservoir in South Africa’s Western Cape starkly illustrate the critical state of the province’s water supply. The Theewaterskloof reservoir is the largest in the province but by the start of November 2017 it had dropped to 27% of capacity. The Western Cape government declared the province a disaster area in May 2017. With the rainy season (April through September) now past, hopes that the drought would ease this year have faded. Notice the tan “bathtub ring” of exposed sediment around the edges of the basin – an indication of lowered water levels.
Hundreds of fires burning in eastern Africa are shown in red. The location, widespread nature, and number of fires suggest that these fires were deliberately set to manage land. Farmers often use fire to return nutrients to the soil and to clear the ground of unwanted plants. While fire helps enhance crops and grasses for pasture, the fires also produce smoke that degrades air quality. In southern Africa, the agricultural burning season usually runs from June through September when the next growing season begins.
Clouds gather over Umnak Island and its volcanic neighbours in the Aleutian Island chain. Part of the Fox Islands, Umnak is the third largest in the Aleutian chain and lies just south-west of Unalaska. Located within the Alaska Maritime National Wildlife Refuge, the island is rich with natural wonders, with abundant wildflowers, berries, mosses, and grasses in the warmer seasons; black sand beaches; and plenty of wild reindeer. Being a volcanic island, Umnak has numerous mud pots, hot springs, and the only geysers in Alaska. The landscape is dominated by volcanoes. On the northern half of the island, Okmok – site of a 2008 eruption – rises 1,073m above sea level. Mount Vsevidof, a symmetrical stratovolcano, rises 2,149m and dominates the skyline of the southern portion of Umnak Island. The volcanic Islands of the Four Mountains are also visible in the lower left of the wide image.
Before and after images showing the retreat of Pine Island glacier, one of the main outlets where ice from the west Antarctic ice sheet flows into the ocean. The glacier calved a large new iceberg, named B-44. Just weeks later, the berg had fractured into more than 20 smaller bergs.
Lake Willis and Lake Hazlett in the Great Sandy desert in Western Australia. Hundreds of ephemeral salt lakes are peppered throughout the arid Australian outback. When occasional floodwaters pour into the lakebeds and then evaporate, they leave salt mineral deposits and create bright, expansive layers that are readily visible from space. The reddish-brown linear sand dunes are slightly higher in elevation and mirror the wind direction. The Pintubi tribe and other Australian Aborigines survived around these lakes for thousands of years in what is now called the Kiwirrkurra community.
Parts of northern California were ravaged by intense and fast-burning wildfires that broke out on 8 October. Blazes that started on a few hundred acres around Napa Valley were fanned by strong north-easterly winds, and by 10 October, the 14 fires had consumed as much as 100,000 acres of land.
The Israeli Dead Sea Works extracts potash, bromine, caustic soda, magnesium, and table salt from the southern end of the Dead Sea using these evaporation pans. The shores of the Dead Sea are Earth’s lowest point of dry land – sitting 430m below sea level. Its water is almost 10 times saltier than the sea.
Low cloud over central China fills the Sichuan Basin - flat, fertile lowlands comprised of low hills and plains and ringed by mountains. The surrounding mountains tend to impede free circulation of air across the basin. This helps moderate the winter temperature, by stopping the flow air from Central Asia. However, because the Sichuan Basin also enjoys high humidity, fog and haze in the basin are frequent. The western part of the Basin averages more than 300 days a year of fog.
A long, narrow stream of clouds, storms and moisture stretched across the Pacific Ocean for more than a week. Called “atmospheric rivers”, such features are relatively common in the north Pacific in the fall and winter, routinely bringing heavy rains and snow to the Pacific north-west and California. What made the October 2017 atmospheric rivers most notable was their length. At times, the flow of moisture extended roughly 5,000 miles (8,000km) from Japan to Washington.