February 5th, 2010 Category: Snapshots

Paraguay - January 25th, 2010

The Gran Chaco is a sparsely populated, hot and semi-arid lowland region of the Río de la Plata basin, divided between eastern Bolivia, Paraguay, northern Argentina and a portion of the Brazilian states of Mato Grosso and Mato Grosso do Sul, where it is connected with the Pantanal region. This land is sometimes called the Chaco Plain.

Historically the Chaco has been divided in three main parts: the Chaco Austral or Southern Chaco, inside Argentinian territory; the Chaco Central or Central Chaco, also now in Argentinian territory; and the Chaco Boreal or Northern Chaco, inside Paraguayan territory and sharing some area with Bolivia.

This image focuses on the Chaco Boreal in Paraguay. The area in the center appears tan due to agricultural fields, many of which are near mennonite colonies. Inside Paraguay, people sometimes use the expression Central Chaco to refer to this area, located roughly in the middle of the Chaco Boreal, where such mennonite colonies are established.

The Chaco offers high soil fertility and a topography that is favorable for agricultural development, but in combination with aspects that are challenging for farming: a semi-arid to semi-humid climate (600–1300 mm annual rainfall) with a six-month dry season and sufficient fresh groundwater available only in roughly one third of the region, the remainig aquifers been too salty.

Tags: Agriculture Central Chaco Chaco Boreal Filadelfia Gran Chaco Northern Chaco Paraguay Río de la Plata Basin South America |  Print This Post |  Email This Post | | Leave a comment

January 21st, 2010 Category: Image of the day

Libya - December 16th, 2009

The Messak Sattafat plateau rises above the sand dunes of the Sahara Desert in Fezzan, a south-western region of modern Libya. Fezzan is thus divided into two sub-basins by the Messak Sattafat, a Nubian Sandstone escarpment and associated dip-slope plateau.

The region as a whole is largely desert but broken by mountains, uplands, and dry river valleys (wadis), where oases enable ancient towns and villages to survive deep in the otherwise inhospitable Sahara. Upon opening the full image, two agricultural areas of circular irrigated fields can be observed in the upper half of the image, both north and south of the Messak Sattafat plateau.

Tags: Africa Agriculture Fezzan Libya Messak Sattafat Sahara Desert Sand Dunes |  Print This Post |  Email This Post | | Leave a comment

January 7th, 2010 Category: Rivers

USA - November 8th, 2009

The Mississippi River (right) forms most of Arkansas’s eastern border, except in Clay and Greene counties and in dozens of places where the current channel of the Mississippi has meandered from where it had last been legally specified.

Arkansas is a land of mountains and valleys, thick forests and fertile plains. The so-called Lowlands are better known by names of their two regions, the Delta and the Grand Prairie. The Arkansas Delta is a flat landscape of rich alluvial soils formed by repeated flooding of the adjacent Mississippi. Further away from the river, in the southeast portion of the state, the Grand Prairie consists of a more undulating landscape. Both are fertile agricultural areas.

Tags: Agriculture Arkansas Arkansas Delta Grand Prairie Mississippi River |  Print This Post |  Email This Post | | Leave a comment

January 6th, 2010 Category: Snapshots

Mexico - December 20th, 2009

This orthorectified image shows agricultural areas and mountains in the Mexican state of Sonora near the Sea of Cortez (Gulf of California). In this state, irrigated fields account for about 96.5% of the total lands harvested. In irrigated areas, crops such as wheat, cotton, watermelons, sesame, chick peas, sorghum, corn and grapevines are all grown.

Upon opening the full image, the city of Hermosillo can be seen towards the top. It is the largest city and capital of the Mexican state of Sonora, and is located in the center of the state, 167 miles (270 kilometers) from the border with the United States. Hermosillo is known for its extreme hot weather because it is located in the Sonoran desert. For three months per year Hermosillo has an average of 40°C or 50°C or more, making it one of the hottest cities in Mexico.

Tags: Agriculture ASAR Gulf of California Hermosillo Irrigation Mexico Orthorectification Sea of Cortez Sonora |  Print This Post |  Email This Post | | Leave a comment

January 5th, 2010 Category: Image of the day, Lakes, Rivers

Sudan - December 16th, 2009

Despite its greenish appearance, the river flowing northward across the left side of this image is the White Nile. Flowing diagonally across the right side is the Blue Nile.

The expansive, green agricultural area between the two rivers are the fields of the Gezira Scheme in Sudan’s Al Jazirah state. The scheme uses an extensive series of canals and ditches to distribute water to farms in the area.

Upon opening the full image and following the Blue Nile southward, the reservoir created by the Sennar Dam can be observed. The dam, located near the town of Sennar, was built in 1925 to provide water for crop irrigation in the Al Jazirah region. It is 3025 meters (9925 feet) long, with a maximum height of 40 meters (130 feet).

Tags: Africa Agriculture Al Jazirah Blue Nile Gezira Scheme Irrigation Sennar Dam Sennar Reservoir Sudan White Nile |  Print This Post |  Email This Post | | Leave a comment

January 3rd, 2010 Category: Image of the day

USA - December 14th, 2009

The Sangre de Cristo Range cuts diagonally across the upper part of this orthorectified image. It is a narrow mountain range of the Rocky Mountains running north and south along the east side of the Rio Grande Rift in southern Colorado in the United States.

The mountains extend southeast from Poncha Pass for about 75 miles (120 km) through south-central Colorado to La Veta Pass, approximately 20 miles (32 km) west of Walsenburg, and form a high ridge separating the San Luis Valley on the west, in which many circular fields are visible, from the watershed of the Arkansas River on the east.

At the foot of the range in the lower right quadrant is the Great Sand Dunes National Park and Preserve, located in the easternmost parts of Alamosa County and Saguache County, Colorado. The park has approximately 85,000 acres (340 km², 130 mi²) and contains the tallest sand dunes in North America, rising about 750 feet (230 m) from the floor of the San Luis Valley on the western base of the Sangre de Cristo Range, covering about 19,000 acres (77 km²).

Tags: Agriculture Alamosa County Circular Crops Colorado Great Sand Dunes National Park and Preserve La Veta Pass Poncha Pass Rio Grande Rift Rocky Mountains Saguache County San Luis Valley Sangre de Cristo Range USA Walsenburg |  Print This Post |  Email This Post | | Leave a comment

January 1st, 2010 Category: Rivers

Georgia - November 24th, 2009

Several rivers flow down into agricultural areas in Russia (above) from the Northern Caucasus Mountains in Georgia (below). The Terek River can be seen towards the center upon opening the full image, differing slightly in color from other nearby rivers due to its dark brown sediment load.

The Terek rises in Georgia near the juncture of the Greater Caucasus Mountain Range and the Khokh Range, to the southwest of Mount Kazbek, then flows north through North Ossetia and into the Caspian Sea. The river is a key natural asset in the region, being used for irrigation and hydroelectric power in its upper reaches.

Tags: Agriculture Caucasus Mountains Georgia Greater Caucasus Mountains Khokh Range Northern Caucasus Mountains Russia Terek River |  Print This Post |  Email This Post | | Leave a comment

December 30th, 2009 Category: Snapshots

Brazil - November 15th, 2009

The north-south border between the Brazilian states of Bahia (right) and Tocantins (left, above) and Goias (left, below) appears as a line running down the left side of the image.

Tan agricultural areas stretch eastward into the state of Bahia from the border, while the terrain on the Tocantins and Goias side is bright green. In the agricultural areas, both rectangular and circular fields can be seen upon opening the full image.

The border actually runs along the edge of a 800 to 1000 meter high plateau in Bahia. The states of Tocantins and Goias lie below, after a drop-off of 200 meters.

Tags: Agriculture Bahia Brazil Circular Crops Goiás South America Tocantins |  Print This Post |  Email This Post | | Leave a comment

December 23rd, 2009 Category: Lakes, Rivers

Egypt - December 16th, 2009

Sediments pouring from the Nile River into the southern end of Lake Nasser cause the lower reaches of the reservoir to appear greenish. The lake, located in southern Egypt and northern Sudan, was created due to the construction of the Aswan High Dam on the Nile.

Also appearing greenish in color is a smaller body of water visible west of the reservoir. This is one of the Toshka Lakes,  created by excess waters drained from Lake Nasser to prevent its water level from becoming too elevated. Some circular fields, irrigated with water drained from Lake Nasser, are visible near the Toshka Lake.

Tags: Agriculture Circular Crops Egypt Irrigation Lake Nasser Nile River Sudan Toshka Lakes |  Print This Post |  Email This Post | | Leave a comment