OCTOBER 2007

SEPTEMBER 2007

SEPTEMBER 2006

WHERE THESE CLOUDS CAME FROM

MORE CLOUDS

NASA - Tucked into a pocket between the Canadian provinces of New Brunswick and Nova Scotia, the Bay of Fundy is famous for dramatic differences between its high and low tides. In fact, the tides observed here are tied with Ungava Bay (located farther north) for the largest tides on Earth. Under typical conditions, high tide at the head (the most inland part) of the Bay of Fundy is as much as about 56 feet higher than low tide.

The large tides in the Bay of Fundy result from tidal resonance. Tidal resonance occurs when the amount of time it takes a large wave to travel from the mouth of a bay to the far shore and back to the mouth is the same, or nearly the same, as the time between the high and low tides. This coincidence means that the general sloshing of the water around the bay can become synchronized with the lunar tides, amplifying their effect. When other factors come into play, such as storm surges, the tides in the Bay of Fundy have exceeded 20 meters. MORE

NASA - On May 23, Flight Engineer Jeff Williams from International Space Station Expedition 13 took this picture of the Cleveland Volcano in the Aleutian Islands. A bank of fog is a common feature around the islands. Two hours later, the plume had completely detached from the volcano The AVO reported that the ash cloud height could have been as high as 20,000 feet above sea level. Cleveland Volcano, situated on the western half of Chuginadak Island, is one of the most active of the volcanoes in the Aleutian Islands, which extend west-southwest from the Alaska mainland. It is a stratovolcano, composed of alternating layers of hardened lava, compacted volcanic ash, and volcanic rocks.

APRIL 2006

NASA - Around the world, agricultural practices have developed as a function of topography, soil type, crop type, annual rainfall, and tradition. This montage of six images shows differences in field geometry and size in different parts of the world.

NASA - Large ice shelves such as the Ross Ice Shelf on the western Antarctica coastline undergo periodic episodes of large-scale iceberg calving. In 2000, several large pieces of the shelf broke off and wandered around in the Ross Sea, breaking into several smaller bergs over the next few years. Among the survivors of the initial calving event is piece C-16. In late March 2006, C-16 worked its way northward along the coastline and plowed into the tip of the Drygalski Ice Tongue. The collision knocked loose a chunk from the tip of the ice tongue.

These images show iceberg C-16 and the Drygalski Ice Tongue before and after the collision. On March 26, the table-like C-16 was poised at the southern edge of the ice tongue, but buffered from direct contact by a small wedge of sea ice. According to scientists at the Space Science and Engineering Center at University of Wisconsin, Madison, who monitor the activity, C-16 had to overcome strong winds, known as katabatic winds, that blow down the topographic incline from the top of David Glacier (the source of the ice tongue) toward the sea. The katabatic winds would have been driving the berg toward the east, but not strongly enough to completely clear the ice tongue. The image from March 31 shows that C-16 had clipped the tip of the ice tongue, breaking off a piece. By April 3, both pieces of ice had swung around to the other side of the ice tongue.