February 9th, 2010 Category: Mountains

Algeria - January 3rd, 2010

The Tassili N’Ajjer National Park, in the Tassili N’Ajjer Mountains, is a World Heritage Site in Algeria. It is located on a plateau of outstanding scenic and geological interest (dark brown areas), covered by eroded sandstone forests of rock.

The area is a floristic and faunal island of Sahelian life in the middle of the desert, and harbors a relict Mediterranean cypress, one of the rarest trees in the world. It also has one of the largest and best preserved groupings of prehistoric cave art in the world, an immense gallery of neolithic art of international importance.

The park has a surface area of 8,000,000ha (Biosphere Reserve 7,200,000ha). It is located in the central Sahara in far southeastern Algeria. The northern boundary runs east 440 kilometers (km) from Amguid on the Tamanrasset road via Illizi to the Libyan border. The east and south sides adjoin the Libyan and Nigerien borders for 600km. The southern boundary runs northwest 700km from the Nigerien border to Amguid, bulging in to exclude the sands of Erg d’Admer.

Tags: Africa Algeria Sahara Sahel Tassili N'Ajjer Mountains Tassili n'Ajjer National Park |  Print This Post |  Email This Post | | Leave a comment

February 4th, 2010 Category: Phytoplankton

Phytoplankton Off Coast of Namibia - January 25th, 2010

A greenish phytoplankton bloom is visible off the coast of Namibia in the lower left hand corner. Such blooms occur frequently in the Atlantic Ocean off southwest Africa, due to cold, nutrient-rich currents that move northward from Antarctica and interact with the coastal shelf.

Simultaneously, the easterly trade winds move surface water away from the coast, permitting water from the ocean’s depths to bring iron and other nutrients to the surface. These nutrients from the currents and upwelling water create a very favorable environment for phytoplankton.

Incredibly, phytoplankton blooms occur so frequently off the Namibian shores that they actually cause a loss of dissolved oxygen in the waters when they die and decompose. After the phytoplankton die, they sink and are consumed by bacteria, which use the dissolved oxygen in the process of breaking down the tiny plants. When dead phytoplankton are overly abudant, the bacteria use all of the available oxygen in the water, creating an area in the ocean where fish cannot live.

In turn, anaerobic bacteria, which do not require oxygen, take over the process of breaking down the phytoplankton, simultaneously releasing sulfur dioxide. The sulfur dioxide then interacts with the ocean water and creates poisonous hydrogen sulfide gas, which may kill fish as it moves to the surface.

Tags: Africa Atlantic Ocean Namibia Phytoplankton |  Print This Post |  Email This Post | | Leave a comment

February 3rd, 2010 Category: Mountains, Snapshots

Mauritania - January 8th, 2010

This pattern of concentric circles in the Saharan Desert near Ouadane, in Mauritania, is known as the Richat Structure. Due to its bullseye-like shape, it was originally believed to be a crater from a meteorite impact. However, scientists now believe that it is a circular anticline whose crest has been eroded away.

The structure is at least 40 km in diameter. Erosion has created circular cuestas represented by three nested rings dipping outward from the structure. The center of the structure consists of a limestone-dolomite shelf that encloses a kilometer-scale siliceous breccia and is intruded by basaltic ring dikes, kimberlitic intrusions, and alkaline volcanic rocks.

Tags: Africa Circular Anticline Mauritania Meteorite Impact Ouadane Richat Structure Sahara Desert |  Print This Post |  Email This Post | | Leave a comment

February 2nd, 2010 Category: Dust Storms, Image of the day

Dust Off Coast of Senegal - January 26th, 2010

Dust blows southwestward off the coast of western Africa, from the Cap-Vert peninsula in Senegal southward. Offshore, it blows under the Cape Verde islands, on the left side of the image, while on the mainland it covers parts of Senegal, the Gambia and Guinea-Bissau.

It does not, however, extend northward of the Cap-Vert peninsula and into Mauritania, which is visible in the full image. There, sediments can be seen along the coastline, and a bright green phytoplankton bloom is visible in the Bay of Arguin.

Tags: Africa Bay of Arguin Cap-Vert Cape Verde Dust Guinea-Bissau Mauritania Senegal The Gambia |  Print This Post |  Email This Post | | Leave a comment

February 1st, 2010 Category: Rivers

Morocco - January 8th, 2010

The Moroccan city of Ouarzazate, often called “the door of the desert”, appears as a green oasis between mountains and desert in the upper left corner. It is the capital of Ouarzazate Province in the Souss-Massa-Draâ region of southern-central Morocco. As of 2004 it had a population of 56,616.

Ouarzazate is located at an altitude of 1,160 m in the middle of a bare plateau, south of the High Atlas Mountains. To the south of the town is the desert. The town is chiefly inhabited by Berbers, who constructed many of the prominent kasbahs and buildings for which the area is known.

Here, the Draa River, the longest in Morocco, can be seen flowing down from the High Atlas Mountains in the upper left corner, past Ouarzazate, and diagonally across the image towards the southeast. The green of the Draa Valley appears as a green ribbon surrounding the river.

Tags: Africa Draa River Draa Valley High Atlas Mountains Morocco Ouarzarzate Sahara Desert Souss-Massa-Draâ Region |  Print This Post |  Email This Post | | Leave a comment

January 30th, 2010 Category: Image of the day, Volcanoes

Equatorial Guinea - December 20th, 2009

Bioko, lower left quadrant, is an island off the west coast of Africa in the Gulf of Guinea. It is part of Equatorial Guinea despite its proximity to Cameroon (top). Bioko has a total area of 2,017 km2 (779 sq mi). It is 70 km long from north-northeast to south-southwest, and about 32 km across. It is volcanic and very mountainous with the highest peak Pico Basile (3,012 m (9,882 ft)). It lies on the Cameroon Volcanic Line.

In this orthorectified image, the city of Malabo can be seen on the northern coast of Bioko. The city, which is the capital of Equatorial Guinea, is located on the rim of a sunken volcano. Its population has grown rapidly over the past ten years to about 100,000.

Tags: Africa ASAR Bioko Island Cameroon Cameroon Volcanic Line Equatorial Guinea Gulf of Guinea Malabo Orthorectification |  Print This Post |  Email This Post | | Leave a comment

January 30th, 2010 Category: Vegetation Index

Liberia - January 2nd, 2010

This FAPAR image stretches from Sierra Leone (west) and Liberia (east) along the coast of Africa, across Guinea (center) to southwestern Mali (top). Parts of Côte d’Ivoire are also visible in the bottom right quadrant, east of Liberia.

The coastal areas of Sierra Leone, Liberia and Côte d’Ivoire appear green, indicating good photosynthetic activity. As one moves inland towards Mali, this green fades to light yellow, indicating the low photosynthetic activity that is to be expected of the semi-arid Sahel, below the Sahara Desert.

Tags: Africa Côte d'Ivoire FAPAR Guinea Liberia Mali Sahara Desert Sahel Sierra Leone |  Print This Post |  Email This Post | | Leave a comment

January 29th, 2010 Category: Snapshots

Egypt - January 3rd, 2010

These circular fields arranged in square and linear patterns are part of the New Valley Project in Egypt. The goal of this project is to irrigate the arid Sahara in the Western Desert of Egypt, in order to make it possible to develop agricultural and industrial communities.

The irrigation is realized by a system of canals that carry water from Lake Nasser.  Upon completion, it is hoped that the Egypt’s arable land area will have increased by 10%, providing more food for the country’s rapidly growing population.

Earlier satellite image show the progress being made; please click here to see previous images of the area. Upon comparison it can be observed that the numbers of fields has increased over the last few months.

Tags: Africa Circular Crops Egypt Irrigation Lake Nasser New Valley Project Sahara Desert Western Desert |  Print This Post |  Email This Post | | Leave a comment

January 27th, 2010 Category: Rivers

Mali - January 6th, 2010

The Niger Inland Delta (also known as the Inner Niger and Macina Inland Delta) is a large area of lakes and floodplains in the Sahel area of central Mali, just south of the Sahara desert, forming a green oasis in its semi-arid surroundings. The delta consists of the middle course of the Niger River, between the bifurcated Niger and its tributary, the Bani, which from here run north towards the desert.

As the Niger Inland Delta lies in the Sahelian zone, it has an ecosystem that is largely dependent on the amount of flooding it receives. Due to its proximity to the widening Sahel, there have been concerns that it may be getting less rain every year. This strongly affects land use in and around the inland delta, as human impact is driven by agriculture, both irrigated and rainfed, grazing and browsing of herds and flocks and the collection of wood for fuel, all dependent on the availability of water.

Tags: Africa Bani River Inner Niger Delta Macina Inland Delta Mali Niger Inland Delta Niger River Sahara Desert Sahel |  Print This Post |  Email This Post | | Leave a comment