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Drifting Iceberg
NASA’s Terra and Aqua satellites captured these images of iceberg B17-B drifting from the ice shelves of Antarctica toward the coast of Australia.
After breaking off (calving) from the ice shelves, most icebergs are swept up in the strong currents that circle Antarctica. Some escape and drift northward. A rare few manage to drift as far as Australia.
During an iceberg’s travel, pieces break off. Over one week, B17-B lost about 25 square kilometers (9.6 square miles) of ice. In mid-December, B17-B was spotted about 1,700 kilometers (1,054 miles) off Australia’s southwest coast.
IImages courtesy of Jesse Allen and the University of Wisconsin’s Space Science and Engineering Center
Harmful Algal Blooms
NASA’s EO-1 satellite captured this image over Guatemala’s Lake Atitlán on November 27, 2009. The green swirls on the lake surface are cyanobacteria, also known as blue-green algae. The dark blue lines (arrow) are paths cut through the algae by boats traveling to and from the city of Panajachel.
When light and nutrient conditions are ideal, the algae grow very quickly, creating a “bloom.” Nutrients introduced by increased agricultural and sewage runoff have fed and maintained this bloom since October. Not only are the algae toxic, but in large numbers they will also deplete the water of its oxygen, creating a “dead zone” where other organisms cannot survive.
Image courtesy of Jesse Allen and the NASA EO-1 team
Snow Buries Mid-Atlantic U.S.
On December 19, 2009, a massive snow storm hit the mid-Atlantic United States, depositing between 12 and 30 inches of snow in Virginia, Maryland, and Washington, D.C.
NASA's Aqua Satellite captured this view of the Chesapeake Bay region on the following day. The thick snow cover highlights the boundaries of the Potomac and Susquehanna Rivers, as well as the ridges and valleys of the Appalachian Mountains.
Image courtesy of Jesse Allen, MODIS Rapid Reposnse Team, NASA/Goddard Space Flight Center
Shrinking of the Aral Sea
Located in central Asia, the Aral Sea was once the fourth-largest lake in the world. In the 1960s, the rivers that fed it were redirected for crop irrigation, and the Aral Sea began to shrink. The drop in water level was so severe that it split the lake in two, creating the North and South Aral Seas.
Declining lake levels have altered the local climate, and the increased occurrence of dust storms has been linked to rising rates of infectious disease. Conservation efforts have helped the North Aral Sea recover, but the South Aral Sea continues to disappear.
NASA’s Terra satellite captured this image on August 16, 2009. The inset image, taken by the Landsat 1 satellite, reveals the water levels that existed in 1973.
Terra image courtesy of MODIS Land Rapid Response Team at NASA/GSFC & Landsat image courtesy of UNEP
Flooding of the Amazon Basin
Located in Brazil, the Amazon is the world's largest tropical rainforest. It is the drainage basin for the Amazon River and its tributaries, and covers an area almost equal in size to the continental United States. Every year between June and October the basin floods, and no two flood events are ever the same. NASA's EO-1 satellite captured these images over the Amazon and Negro Rivers, near the city of Manaus. In mid-June 2009, water levels on the Negro River reached their highest in 56 years. In 2004, flooding was less extreme. The small, white specks along the riverbanks are buildings.
Images courtesy of Jesse Allen & NASA's EO-1 Team
Dust Storm in Argentina
NASA's Aqua satellite captured this image over Argentina's largest lake, Laguna Mar Chiquita, on August 16, 2009. A severe drought dried up a large portion of the shallow salt lake. Winds picked up the exposed lake bed sediments, creating two thick plumes of dust. The winds carried the debris more than 200 kilometers (124 miles) to the north.
The red boxes indicate the locations of fires.
Image courtesy of MODIS Rapid Response Team, NASA/Goddard Space Flight Center
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