Thursday, June 28, 2012

VIDEO: Sand storm in Saharan Africa deposits 'dust' 2000 miles away in parts of UK - @metoffice

28 06 2012

Many people across parts of the UK have noticed a layer of light dust on their cars or other surfaces over the past couple of days, but how did it get here?

A big dust storm in the Sahara, around 2,000 miles away, is to blame.

Late last week the storm swept up a large amount of sand and dust from the western Sahara up into the atmosphere.

It then spread westwards out over the Atlantic before getting caught up in southerly winds, dragging it north over Spain before it arrived over the UK mixed up in the warm and humid air which has brought thunder storms and heavy rain to the country.

The dust can get caught up in the rain droplets in clouds, which then fall to the ground. When the water evaporates, a thin layer of dust is left on surfaces, like cars.

Many people noticed this in the South West of the UK yesterday, with the dust then spreading north and east overnight to bring it to a much wider area.

Paul Hutcheon, Deputy Chief Forecaster at the Met Office, said: “We usually see this happen several times a year, particularly in summer when you get these big dust storms in the western Sahara and the southerly winds to bring that dust here.

“This event was a very well-marked example, as you can clearly see the dust as it moves from the Sahara to the UK in the satellite imagery.”

The satellite animation above shows the dust as a bright pink blob over Africa at the start of the sequence, which then moves north over to the UK – initially arriving over the South West, but then moving north and east. You can clearly see the dust-laden airmass of warm and humid air, with a marked boundary to the clear air from a cold front to the west.