January 18th, 2010 Category: Image of the day

Morocco - January 2nd, 2010

Sediments frame the western coasts of Morocco (below) and Spain (above) and flow from the Atlantic Ocean (left) through the Strait of Gibraltar into the Mediterranean Sea (right). Although water moves in both directions between the two bodies of water, on the whole and over time, the balance of the water flow is eastwards, due to an evaporation rate within the Mediterranean basin that is higher than the combined inflow of all the rivers that empty into it.

To the south, the Atlas Mountains can be seen running diagonally across Morocco and into Algeria. The entire range extends about 2,500 km (1,500 miles), all the way east to Tunisia. The Sahara Desert can be observed below this range. Another shorter range, the Rif Mountains, are visible just below the strait. These mountains are not part of the Atlas chain.

Tags: Africa Algeria Atlas Mountains Europe Mediterranean Sea Morocco Rif Mountains Sahara Desert Spain Strait of Gibraltar |  Print This Post |  Email This Post | | Leave a comment

October 13th, 2009 Category: Image of the day

Strait of Gibraltar - August 27th, 2009

Close-up of strait

Moroccan coast

The main image here is an orthorectified wide-swath ASAR (radar) image of southern Spain and northern Morocco. It is possible to see a larger area as the width of the swath is five times that of a normal IMM image.

The first close-up focuses on the northeastern coast of Morocco near the port city of Al Hoceima, by the center of the Rif Mountains.

The second close-up focuses on the Strait of Gibraltar. Ships can be seen moving through the strait and clustered around the port city of La Línea de la Concepción, on the eastern isthmus of the Bay of Gibraltar, and the nearby British overseas territory of Gibraltar (right edge).

Tags: Al Hoceima Bay of Gibraltar Gibraltar La Línea de la Concepción Morocco Orthorectification Rif Mountains Spain Strait of Gibraltar Wide-swath |  Print This Post |  Email This Post | | Leave a comment

August 20th, 2009 Category: Snapshots

Strait of Gibraltar - August 12th, 2009

The waters of the Strait of Gibraltar (left) and the Mediterranean Sea (right) show a rippled pattern of internal waves. These are gravity waves that oscillate within, rather than on the surface of, a fluid medium. They arise from perturbations to hydrostatic equilibrium, where balance is maintained between the force of gravity and the buoyant restoring force.

A few ships can be seen passing through the strait separating Spain (above) and Morocco (below). However, the greatest number of vessels is concentrated around the self-governing British overseas territory of Gibraltar, located on the southern end of the Iberian Peninsula at the entrance of the Mediterranean.

This image has been orthorectified so that the land around the strait can be observed free of geometric distortion.

Tags: Gibraltar Internal Waves Mediterranean Sea Morocco Orthorectification Spain Strait of Gibraltar |  Print This Post |  Email This Post | | Leave a comment

June 30th, 2009 Category: Snapshots

Strait of Gibraltar - June 21st, 2009

Clusters of white dots along the coastlines of Spain (above) and Morocco (below) indicate the locations of populated or industrial areas, while other white dots in the Strait of Gibraltar (center) mark the presence of ships.

The bright white area at the lower left of this orthorectified ASAR (radar) image is the port city of Tangiers, Morocco, while that at the lower right is the Spanish enclave of Ceuta.

Across the strait, Spanish cities such as Algeciras and La Línea de la Concepción are visible in the upper right quadrant, with Tarifa visible in the center of the image. The bright white peninsula on the coastline, just south of La Línea, is the British Overseas Territory of Gibraltar.

Tags: Algeciras Ceuta Gibraltar La Línea de la Concepción Morocco Orthorectification Spain Strait of Gibraltar Tangiers Tarifa |  Print This Post |  Email This Post | | Leave a comment

April 28th, 2009 Category: Snapshots

Morocco - April 9th, 2009

Much of the northern half of Morocco, not including the disputed Western Sahara to the South, can be seen here, from fertile coastal plains, to steep mountains, to arid desert.

To the north, Morocco is bordered by and controls part of the Strait of Gibraltar, giving it power over the waterways in and out of the Mediterranean sea. Southern Spain and Portugal can be seen to the North.

The Rif mountains occupy the region bordering the Mediterranean from the North-west to the North-east. The land around them is fertile and green.

The Atlas Mountains, on the other hand, run down the backbone of the country, from the south west to the north east. Some of their peaks are capped with snow in this image.

Most of the population lives to the North of these mountains, particularly in the coastal areas. Sediments can be seen framing the coast; discharge is particularly heavy near Morocco’s capital city, Rabat, and its largest city and main port, Casablanca.

Moving away from the coast, across the Atlas Mountains, most of the south east portion of the country is in the Sahara Desert. As such it is, in general, sparsely populated and unproductive economically.

Tags: Atlantic Ocean Atlas Mountains Casablanca Mediterranean Sea Morocco Portugal Rabat Rif Mountains Sahara Desert Spain Strait of Gibraltar |  Print This Post |  Email This Post | | Leave a comment

April 11th, 2009 Category: Snapshots

Condensation trails over Portugal and Spain - April 9th, 2009

Many condensation trails (or contrails) from aircraft criss-cross the skies over southern Portugal (left) and Spain (right), north of the Strait of Gibraltar. In the parts of Europe and eastern North America with the heaviest air traffic, contrails can cover up to 3.8 percent and 5.5 percent of the sky, respectively, according to a study from the Geophysical Research Letters.

Condensation trails also contribute to global warming by affecting the Earth’s radiation balance, thus acting as a radiative forcing. Studies have found that contrails trap outgoing longwave radiation emitted by the Earth and atmosphere (positive radiative forcing) at a greater rate than they reflect incoming solar radiation (negative radiative forcing).

Therefore, the overall net effect of contrails is positive, i.e. a warming. However, the effect varies daily and annually, and overall the magnitude of the forcing is not well known: globally (for 1992 air traffic conditions), values range from 3.5 mW/m² to 17 mW/m².

Other studies have determined that night flights are mostly responsible for the warming effect: while accounting for only 25% of daily air traffic, they contribute 60 to 80% of contrail radiative forcing. Similarly, winter flights account for only 22% of annual air traffic, but contribute half of the annual mean radiative forcing.

Tags: Condensation Trails Portugal Spain Strait of Gibraltar |  Print This Post |  Email This Post | | Leave a comment

March 29th, 2009 Category: Image of the day

Spain - February 24th, 2009

Spain is a country located in southwestern Europe on the Iberian Peninsula. With an area of 504,030 km², it is the second largest country in Western Europe after France.

Its mainland is bordered to the south and east by the Mediterranean Sea except for a small land boundary with Gibraltar; to the north by France, Andorra, and the Bay of Biscay; and to the west by the Atlantic Ocean and Portugal.

Spanish territory also includes the Balearic Islands in the Mediterranean, the Canary Islands in the Atlantic Ocean off the African coast, and two autonomous cities in North Africa, Ceuta and Melilla, that border Morocco.

Northern Morocco and the aforementioned autonomous cities are visible in the below part of the image, separated from Spain by the Strait of Gibraltar. Part of northwestern Algeria is also visible on the lower right. Some dust can be seen east of Morocco, blowing from the desert over the Atlantic Ocean.

The lack of clouds makes it possible to see the differences in the Spanish terrain, from lush green vegetation to orange, arid areas. The country has, in fact, four different climate zones.

Spain has a Continental Mediterranean climate in the inland areas of the peninsula, including Madrid.

A Mediterranean climate region extends from the Andalusian plain along the southern and eastern coasts up to the Pyrenees, on the seaward side of the mountain ranges that run near the coast, including Barcelona. These mountains receive warm winds from the Saharas called Leveche, also known as Sirocco.

In Galicia and the coastal strip near the Bay of Biscay and Bilbao, there is an Oceanic climate. This area is often called Green Spain, as one may have guessed from the color of the vegetation in the image.

Finally,  the Canary Islands enjoy a Subtropical climate, with high humidity.

Tags: Africa Algeria Atlantic Ocean Bay of Biscay Dust Storm Europe Iberian Peninsula Mediterranean Sea Morocco Portugal Pyrenees Spain Strait of Gibraltar |  Print This Post |  Email This Post | | Leave a comment

March 23rd, 2009 Category: Rivers

Strait of Gibraltar - February 24th, 2009

Europe and Africa are separated by 14.24 km (7.7 nautical miles) of ocean at the Strait of Gibraltar’s narrowest point. The strait depth ranges between 300 and 900 metres (980 and 3,000 ft).

Gibraltar and the Spanish city of Algeciras are clearly visible on the strait’s northern shores, while the Moroccan city of Tangier is visible on the southern coast.

Below Tangier, some greenish sediments are being discharged from the Loukous River, near Larache. To the North, on Spain’s western coast, the San Pedro River is pouring a thick tan cloud of sediments into the Bay of Cádiz.

The rest of the coastline of the Strait of Gibraltar, Morocco and Spain is clear of sediments and algae. However, if one looks carefully it is possible to see some sands from a dust storm lingering over the Atlantic Ocean.

Tags: Africa Algeciras Bay of Cádiz Dust Storm Europe Larache Loukous River San Pedro River Sediments Strait of Gibraltar Tangier |  Print This Post |  Email This Post | | Leave a comment

February 14th, 2009 Category: Image of the day, Rivers

Strait of Gibraltar - February 11th, 2009

Close-up of Strait of Gibraltar

The Strait of Gibraltar, which connects the Mediterranean Sea to the Atlantic Ocean, is visible near the center.

Sediments, surrounded by an algal bloom, can be seen flowing into the Atlantic Ocean from various rivermouths in Spain and Morocco.

In comparison, the Strait of Gibraltar is relatively clear, with only a light algal bloom flanking the coasts.

In Spain, great deal of sediments is being discharged from the San Pedro River into the Bay of Cádiz, near the city of the same name.

Along the Moroccan coast, the densest outflow of sediments is near Kenitra, coming from the Sebou River. Further north, there is also a large concentration of sediments pouring out of the Loukos River, near Larache.

Tags: Atlantic Ocean Bay of Cádiz Kenitra Larache Loukos River Mediterranean Sea Morocco San Pedro River Sebou River Sediments Spain Strait of Gibraltar |  Print This Post |  Email This Post | | Leave a comment