Fichier:Modis aral.jpg

Description

Aral Sea 2000 & 2001

“Rebirth” Island Joins the Mainland copie d'archive at the Wayback Machine

The images above, collected by the Moderate-resolution Imaging Spectroradiometer (MODIS) flying aboard NASA's Terra satellite, show how the Aral Sea has changed over the last year (from June 9, 2000, to June 3, 2001). The yellow line superimposed on the scenes reveals the full extent of the Aral Sea in 1970, while the red line represents the border between Kazakhstan and Uzbekistan. The Aral (which is actually a lake) is drying rapidly because the two main rivers that fed it--the Amu Darya and the Syr Darya--had most of their water diverted in order to transform a desert area into cotton and rice plantations.

For 40 years Vozrozhdeniye Island, once isolated in the middle of the lake, hosted the Soviet Union's most important facility for developing and testing biological weapons. (Ironically, Vozrozhdeniye means "renaissance" or "rebirth.") Huge amounts of lethal bacteria are reported to be buried somewhere on the island (see the Federation of American Scientists website for detailed photos and information).

The more detailed MODIS images (insets) show that the small water channel that separated the island from the mainland in the summer of 2000 had vanished by the summer 2001. This means that potentially infected animals living on the island now have easy access to the mainland, and vice versa, with unpredictable consequences for the local biosphere.

The top two images are "true color" combinations of MODIS bands 1, 4, and 3 at a spatial resolution of around 500 meters per pixel. The bottom two images represent a combination of MODIS bands 1 and 2 (red and near infrared) at a spatial resolution of 250 meters per pixel.

	Ce fichier provient de la NASA. Sauf exception, les documents créés par la NASA ne sont pas soumis à copyright. Pour plus d'informations, voir la politique de copyright de la NASA.
	Attention : Les documents provenant du téléscope Hubble sont soumis à copyright s'ils ne sont pas crédités à STScI. Voir les détails. Les documents créés par la sonde SOHO sont soumis à copyright et requièrent une permission pour un usage commercial et/ou non-éducatif. Voir les détails. Les images issues du site web Astronomy Picture of the Day (APOD) sont soumises à copyright. Voir les détails.