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Archive for Climate Change

Vegetation Index of Ghana, Togo, Benin and Nigeria

10.3N 4.6E

November 30th, 2009 Category: Climate Change, Lakes

Nigeria, Benin, Togo & Ghana - November 17th, 2009

Nigeria, Benin, Togo & Ghana - November 17th, 2009

This FAPAR image stretches along the coast of Africa, from Ghana (left), across Togo and Benin, to Nigeria (right). FAPAR stands for Fraction of Absorbed Photosynthetically Active Radiation, which corresponds to the  area’s vegetation index.

In FAPAR images, the color spectrum over land runs from red (1.0), to green, to yellow and white (0.0), while bodies of water, such as Lake Volta in Ghana  (lower left) and Lake Kainji in Nigeria (center), generally appear blue.

High photosynthetic activity is present in dark red regions, such as those along the coast here. Green areas are also productive. Yellow to white areas, on the other hand, indicate a low degree of photosynthetic activity. Here, the more photosynthetically active green areas gradually give way to less activa yellow and white zones as one approaches the drier Sahel, south of the Sahara desert.

Deforestation Near Lake Abitibi, Canada

48.6N 79.8W

November 19th, 2009 Category: Climate Change, Lakes, Rivers

Canada - November 8th, 2009

Canada - November 8th, 2009

The waters of Lake Abitibi appear tan from sediments in this image of northeastern Ontario, Canada. The 931 km² lake is separated in two distinct portions by a short narrows, making it actually two lakes. The lake is shallow and studded with islands. Its shores and vicinity are covered with small timber.

Its outlet is the Abitibi River, seen here exiting the lake on the left and flowing westward. Portions of Lake Abitibi’s western shores and a section of the Abitibi River are part of the Abitibi-de-Troyes Provincial Park.

By contrast, the eastern shores of the lake and the land farther to the east show signs of deforestation, with tan herringbone patterns cutting through the dark green forest. Pulp and paper is an important industry in this heavily forested region.

The beginning of this deforested area corresponds with the border between the provinces of Ontario (left) and Quebec (right). A white dusting of snow covers some areas in Quebec to the northeast of the lake.

Vegetation Index of Coastal Texas as Seen by FAPAR

29.7N 95.3W

November 18th, 2009 Category: Climate Change

USA - November 10th, 2009

USA - November 10th, 2009

This FAPAR image of the coast of Texas along the Gulf of Mexico shows the area’s vegetation index, which corresponds to the Fraction of Absorbed Photosynthetically Active Radiation (from which its name is derived). Measuring the radiation over land surfaces in this way provides data on the planet’s climate system. To compare this FAPAR image to the original satellite view of this area, please click here.

In FAPAR images, the color spectrum over land runs from red (1.0), to green, to yellow and white (0.0), while bodies of water appear blue. Red regions correspond to agricultural zones for which there is high photosynthetic activity and therefore vegetation productivity, while yellow to white areas indicate a low degree of photosynthetic activity.

Here, some red areas can be seen upon opening the full image, but most of the area appears yellow-green to medium green, or between 0.2 and 0.5 on the numerical scale. Yellow and white areas are also present, indicating low photosynthetic activity, particularly to the south. The city of Houston also stands out as a white area near the coast.