St. Pauls Cathedral

17/06/2009

The View from Above

Satellites orbiting the earth are able to give us breathtaking views of all kinds of activity from exploding volcanoes in Chile to dust storms in Asia.

The images and the information they reveal is already helping governments and aid organisations tackle major crises and react to ecological damaging activities, such as deforestation in Bolivia or potential famine in Kenya.

We've collected together some of the most interesting photos featured on the Earth Observatory, a website run by NASA's Earth Observing System Project Science Office (EOSPSO).

Large dust storms, each shown as a light brown mass, are often seen spanning a wide swath of central Asia from Afghanistan, along the length of Turkmenistan, to the Caspian Sea.

The swirls of colour off the west coast of the Yucatan Peninsula, Mexico, are most likely to be sediment in the water. According to NASA, the sediment scatters light, giving the water its colour. Some of the colour may also come from phytoplankton, tiny plant-like organisms that live in the sun-lit surface waters of the ocean.

Images of cities are perhaps the best illustration of the impact of humans on earth.

According to NASA, its night-time photographs show that the lights of Tokyo are a cooler blue-green colour than many other world cities. The colour results from the more widespread use of mercury vapour lighting as opposed to the sodium vapour lighting used elsewhere in the world, which produces an orange-yellow hue.

The Amazon bends through the numerous lakes in its flood plain while the Uatuma River, a tributary, flows into the Amazon from the north.

One of the Kamchatka volcanoes in Russia, Klyuchevskaya, erupted on December 8th 2008. A gap in the clouds above the snow-covered mountain revealed a white plume which NASA believes was either steam or a mixture of steam and ash.

Although not a threat to human settlement, the nearest of which is some kilometres away, the ash from the volcanoes in this area needs to be monitored because of the potential hazard it poses to aircraft.

The eastern half of Bolivia is covered with tropical rainforest but widespread clearing has taken place to make room for agriculture. This stretch of forest shows lighter patches of extensive clearing along the Rio Parapeti in Bolivia.

China’s Yellow River, or Huang He, is the world’s muddiest. Stretching some 5,475 kilometres (3,395 miles) from eastern Tibet to Bo Hai, the river travels through soft plateaus of silt, picking up a massive sediment load on its journey.

In these images you can see the build-up of the beige-coloured sediment around the coastline. NASA says this delta-building process has added several hundred square kilometres of land to China’s coast.

Kenya has experienced several poor harvests recently. Areas in which plants tend to grow less vigorously than average appear brown in satellite imagery, while areas where plants grow well appear green.