Showing posts with label Desertification. Show all posts
Showing posts with label Desertification. Show all posts

Saturday, August 2, 2014

Rub’ al Khali Desert


Rolling sand dunes in the expansive Rub’ al Khali desert on the southern Arabian Peninsula are pictured in this radar image from the Sentinel-1A satellite.

Rub’ al Khali – also known at the ‘Empty Quarter’ – is part of the greater Arabian Desert. Its sand dunes reach up to 250 m in height and in some areas are interspersed with hardened flat plains, evident at this bottom half of this image. These plains are what is left of shallow lakes that existed thousands of years ago, formed by monsoon-like rains and runoff.

Today, the region is considered to be ‘hyper-arid’, with precipitation rarely exceeding 35 mm a year and regular high temperatures around 50°C.

Rub’ al Khali has experienced major desertification over the past 2000 years. Until about the year 300 AD, trade caravans crossed what is today an impassable wasteland.

In the upper part of this image, we can see a road snaking through the remote desert and leading to Kharkhir (not pictured), a Saudi village near the border with Yemen.

Sentinel-1 is a two-satellite radar mission for Europe’s Copernicus program. The first satellite of the pair, Sentinel-1A, was launched in April. The satellite is still being commissioned to prepare for routine operations.

This image is featured on the Earth from Space video program.

Image credit: ESA

Thursday, February 16, 2012

Morocco and Algeria


This Envisat image, acquired on 5 December 2011 by the MERIS instrument, shows part of central Morocco from the Atlantic Ocean to the west, over the Atlas mountains and into arid parts of Algeria further inland. The snow-capped High Atlas mountain range divides Morocco from the Sahara desert’s climatic influences in Algeria. The Sahara is constantly expanding southward, rendering large areas of land barren. One of the many benefits of Earth observation satellites is the possibility to monitor changes like desertification, or the degradation of land, caused by human activities or climate change.

Photo credit: ESA