Earth Snapshot RSS Feed Twitter

Posts tagged Vegetation Index

Comparative Vegetation Index East and West of the Andes

26.6S 68.9W

March 21st, 2013 Category: Vegetation Index

Argentina – March 21st, 2013

The Normalized Difference Vegetation Index (NDVI) is a simple graphical indicator that can be used to analyze satellite data, and assess whether the target being observed contains live green vegetation or not.

Live green plants absorb solar radiation in the photosynthetically active radiation (PAR) spectral region, which they use as a source of energy in the process of photosynthesis. Leaf cells have also evolved to scatter (i.e., reflect and transmit) solar radiation in the near-infrared spectral region. Hence, live green plants appear relatively dark in the PAR and relatively bright in the near-infrared.

The pigment in plant leaves, chlorophyll, strongly absorbs visible light (from 0.4 to 0.7 µm) for use in photosynthesis. The cell structure of the leaves, on the other hand, strongly reflects near-infrared light (from 0.7 to 1.1 µm). The more leaves a plant has, the more these wavelengths of light are affected, respectively.

Since early instruments of Earth Observation acquired data in visible and near-infrared, it was natural to exploit the strong differences in plant reflectance to determine their spatial distribution in these satellite images. Here, the color contrast shows a stark difference in the vegetation index between arid Chile and western Bolivia, which appear brown to yellow (low vegetation index), and more fertile Argentina, which appears green (high vegetation index).

Drought Continues to Afflict Amazon, Brazil

5.7S 63.1W

November 19th, 2010 Category: Climate Change, Vegetation Index

Brazil - November 16th, 2010

In a one-year period the Amazon region has gone through the biggest flood and now the worst drought. Scientists have expressed surprise, saying that they were expecting these extremes would only happen every 50 years.

This FAPAR image focuses on the Amazon Rainforest in Brazil. Here, the vegetation index is highest to the west (rusty red), and good to the east (green), with some areas of low photosynthetic activity (yellow).

The fact that these extreme events are so close may indicate changes in the climate, not only here in Amazonas region of Brazil visible here, but also in the south of Brazil, since the Amazon influences the rains there as well. Deforestation, therefore, affects this entire system.

This drought directly affects the lives of people who live along the rivers. These people depend on the river for transportation, meals, and end up isolated because of the drought. In some areas in the middle of the Amazon basin, people have no water to drink, reported Greenpeace.

Vegetation Index of Myanmar and Northeast India

20.3N 95.3E

November 15th, 2010 Category: Vegetation Index

Myanmar - November 5th, 2010

This FAPAR image shows the vegetation index of Myanmar (formerly known as Burma). The index is highest (rusty red) near the coast on the left side of the image, around the border with northeast India.

The rest of the image shows good to high photosynthetic activity (green to rusty red), with a few areas of low activity (yellow), particularly to the north in the full image. Near the bottom, the Irrawaddy (Ayeyarwady) River can be seen releasing tan sediments into the Andaman Sea.

Vegetation Index of Amazon Rainforest Increases from East to West

6.2S 67W

October 20th, 2010 Category: Vegetation Index

Brazil - October 8th, 2010

This FAPAR image shows the vegetation index of a large section of the Amazon Rainforest, primarily in the Brazilian state of Amazonas. The vegetation index ranges from good (green) to high (rusty red), increasing as one moves from east to west.

Various rivers appear as yellow lines across the image. This yellow color represents a low vegetation index, as one would expect from a body of water. Click here to see a true-color version of the rivers and rainforest in this image.

Vegetation Index of Sakhalin Island and Khabarovsk Krai, Russia

55.0N 137.6E

October 14th, 2010 Category: Vegetation Index

Russia - August 27th, 2010

This FAPAR image focuses on the coastal parts of Khabarovsk Krai, the fourth-largest federal district within the Russian Federation. It has a comparative land area slightly larger than that of the U.S. state of Texas.

Taiga and tundra in the north, swampy forest in the central depression, and deciduous forest in the south are the natural vegetation in the area. Here, the vegetation index appears generally good (green), with some small patches of low (yellow) and high (rusty red) photosynthetic activity.

Also visible is the large Sakhalin Island (right) and the cluster of the smaller Shantar Islands (center left). Sakhalin Island is Russia’s largest island, administered as part of Sakhalin Oblast. The Shantar Islands, on the other hand, belong administratively to Khabarovsk Krai. They are a group of fifteen islands that lie in Uda Bay, in the southwestern zone of the Sea of Okhotsk, close to the shores of the Siberian mainland.