Feeds

Scientists reveal link between Sahara and Amazon

Dust to, er, rainforest, actually

The essential guide to IT transformation

Scientists have conclusively demonstrated the extent of the link between the Sahara desert and the Amazon rainforests.

It might sound unlikely, but their work has shown that the Amazon rainforest depends on dust from one tiny area of the Sahara desert to restock its soil with nutrients and minerals. Analysis of images from NASA's MODIS satellite have revealed the Bodélé, a region of the Sahara not far from Lake Chad, as the source of more than half the material that fertilises the rainforest.

The Bodélé depression was already known as one of the largest sources of dust in the world, but the scientists involved in the research say no one had any idea of the scale of the region's importance to the Amazon. It transpires that if the Bodélé was not there, the Amazon would be a mere wet desert.

Dr Ilan Koren, lead author of the paper said: "Until now no one had any idea how much dust [The Bodélé] emits and what portion arrives in the Amazon. Using satellite data, we have calculated that it provides on average more than 0.7 million tons of dust on each day that it is actively emitting dust."

The dust is swept into the atmosphere by the surface winds in the Sahara. The Bodélé region loses most of its dust during the spring and winter months, unlike the rest of the Sahara, because of its unique geography.

The Bodélé depression is located downwind (in the winter, when the Harmattan winds blow) of a huge crater-like valley between the Tibesti and Ennedi mountains. This crater narrows to a cone-shaped pass which focuses the winds, and they speed up towards the Bodélé. This is how the region, which is just half a per cent of the size of the Amazon, can produce as much dust as it does.

Dr Koren explains the process: "In the early morning on an emission day the winds speed up to the critical velocity for lifting and transporting dust when they reach the Bodélé.

"By using data from two satellites that take images of the same areas three hours apart, we can estimate the wind speed and calculate the size of the 'dust parcels' that are produced at the Bodélé. We are then able to track the progress of the parcel the next day after it has left the Bodélé and watch it progress across the desert."

The research team use the MODIS satellite to watch the dust, and the MISR instrument, which only covers a small area, to find out more about the quantity of dust in each parcel.

The work has prompted more questions, however. The team wants to know how long the Bodélé depression has been 'sending' dust to the Amazon, and how long it will continue to do so.

The research is reported in the first edition of the Institute of Physics open-access journal, Environmental Research Letters. ®

Gartner critical capabilities for enterprise endpoint backup

More from The Register

next story
Boffins attempt to prove the UNIVERSE IS JUST A HOLOGRAM
Is this the real life? Is this just fantasy?
China building SUPERSONIC SUBMARINE that travels in a BUBBLE
Shanghai to San Fran in two hours would be a trick, though
Our LOHAN spaceplane ballocket Kickstarter climbs through £8000
Through 25 per cent but more is needed: Get your UNIQUE rewards!
LOHAN Kickstarter push breaks TWELVE THOUSAND POUNDS
That's right, folks, you've stumped up OVER 9000 beer tokens - and counting
SpaceX prototype rocket EXPLODES over Texas. 'Tricky' biz, says Elon Musk
No injuries or near injuries. Flight stayed in designated area
Galileo, Galileo! Galileo, Galileo! Galileo fit to go. Magnifico
I'm just a poor boy, nobody loves me. But at least I can find my way with ESA GPS by 2017
Astronomers scramble for obs on new comet
Amateur gets fifth confirmed discovery
prev story

Whitepapers

Best practices for enterprise data
Discussing how technology providers have innovated in order to solve new challenges, creating a new framework for enterprise data.
Implementing global e-invoicing with guaranteed legal certainty
Explaining the role local tax compliance plays in successful supply chain management and e-business and how leading global brands are addressing this.
Advanced data protection for your virtualized environments
Find a natural fit for optimizing protection for the often resource-constrained data protection process found in virtual environments.
How modern custom applications can spur business growth
Learn how to create, deploy and manage custom applications without consuming or expanding the need for scarce, expensive IT resources.
High Performance for All
While HPC is not new, it has traditionally been seen as a specialist area – is it now geared up to meet more mainstream requirements?