3 Sep 2013

Our world viewed from space

As a meteorologist, I find satellites are invaluable when it comes to monitoring what goes on in the skies above our planet.

However, high-resolution satellite imagery is also used to keep track of how the surface of the earth is changing over time – from floods to movement of glaciers.

Nasa‘s earth observation project offers a huge selection of pictures showing some of the best imagery available. I thought I’d pull a few of the more recent ones together and describe what they show.

African dust storms

This image taken at the beginning of August shows a large plume of dust leaving the west coast of Africa and spilling out across the skies of the Atlantic ocean.


Carried by winds high up in the atmosphere, this dust can reach as far as the Caribbean and South America, fertilising soils and building beaches.

Dust can also inhibit the formation of hurricanes as the air is very dry. Hurricanes can only thrive in moist air, so the presence of dry air reduces the likelihood of them developing – as has been the case during August.

Cumulus clouds over Sri Lanka

Cumulus clouds form when the sun heats the ground causing bubbles of moist air to rise upwards. When these bubbles of air rise high enough into the sky, the moisture condenses forming clouds.

The two images below show cumulus clouds in the morning (top) and afternoon (bottom).



Comparing these two images show how the clouds grow through the day as temperatures rise and bubbles of air rise upwards more readily.

Also, you’ll notice in the bottom image that the clouds start to form further away from the coast. This is because a sea breeze forms during the day, pushing the cloud development area further inland.

Super Typhoon Utor

The image below shows Super Typhoon Utor poised to hit the Philippines on 12 August as a category 3 storm, with winds around 130mph.


You can clearly see the eye of the storm around which the strongest winds rotate. Towards the edge of the storm, the swirls of cloud are lumpy, indicating thunderstorms in its outer bands.

The storm caused severe flooding and loss as life before continuing on to southern China a few days later.

Severe flooding in Russia

Unseasonably heavy rain hit the far east of Russia during August, with 300mm (12 inches) of rain falling in the first 12 days of the month.

Floodwaters forced more than 10,000 people from their homes and inundated vast areas of farmland with water.

Below, the top image shows the normal path of rivers in the area. The bottom image shows the extent to which the rivers flooded following torrential rain.



Garden and Hog Islands, Michigan

Lake Michigan was formed by retreating glaciers that carved out a huge basin. However, there are some islands that still protrude above the water line.

The image below shows the Garden and Hog islands dominated by dense forests, swamps and sandy beaches. Offshore, shallow waters appear turquoise, deeper waters dark blue and reefs a minty green.


If you enjoyed these images, there are more on their website here. You can also follow the Nasa earth observatory on Twitter – @NASA_EO

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