During a solar eclipse the position of the moon is in between the sun and the earth. Therefore, no sunlight - or less than usual - reaches the earth's surface in the regions where the eclipse can be observed. Solar eclipses are rarely seen at any given location on earth. Nevertheless the phenomenon can be observed somewhere on the Earth’s surface twice, or in favourable occasions even five times a year.

METEOSAT
Most environmental satellites carry sensors that measure reflected sunlight. From these measurements then satellite images are made that can be compared with the images taken by a standard digital camera. The sensors are set up in a way to generate an image of optimal quality given the available amount of sunlight. In areas where the moon catches it's shadow, the amount of sunlight is different. This causes a dark area on the 'standard' images in the visible channel.
The EUMETSAT archives contain several examples of shadows of the moon on the earth's surface during solar eclipses. The black-and-white animations show amongst others the total solar eclipse of February 26 1998 over the Atlantic Ocean and of December 4 2002 over the southern part of the Indian Ocean. Other events shown are the total eclipse of Augustus 11 1999 over Europe and June 21 2002 over the southern Atlantic and Africa.

SeaWiFS
The total eclipse over Europe in 1999 was also observed by the Sea-viewing wide Field-of view Sensor (SeaWiFS) of the American satellite Seastar (Orbview-2). The assumptions of the available amount of sunlight that the computer software used to create the image, were not valid for Greece and Turkey. For that reason the area where the solar eclipse could be observed can easily be seen on the image (figure 3).
The image of the Grate Lakes in the United States and Canada of figure 4 also originates from SeaWiFS data. The images was made during the partial eclipse of December 25 2000. Because the eclipse is only partial, the earth's surface is not as dark as in the case of figure 3. However the yellow-brownish shades and the mustard colour of Lake Erie (the far southeast one of the Great Lakes) differ significantly from what is observed normally.

MODIS

The difference in colour shade can be seen even better on figure 5. This satellite image is based on data from successive passes of the American environmental satellite Terra. Before the start of the solar eclipse the colours that the Moderate Resolution Imaging Spectroradiometer (MODIS) shows are as usual (right hand part of the image). The shades of the other part of the image, that was scanned during the eclipse, are substantially darker.
The Terra satellite also generated the image of the total solar eclipse of November 23 2003 over Antarctica (figure 6). Because of the low position of the sun, the shadow of the moon has become an elongated ellipse. It's shape can be compared with the patch of light on a wall caused by an inclined beam of light from a torch. The earth's surface is covered with snow and ice and is very homogenous; for that reason the umbra and the penumbra can be discerned very easily.
The most recent satellite images are also based on data collected by Terra. They were made during the annular eclipse of October 3 2005 and show the moment that the shadow zone passes the boundary between Niger and Chad (figure 7). The pink-red-brownish shades of the desert when observed under normal conditions (figure 8) have changed to an intense orange.
Let's look forward to seeing the satellite images and satellite loops of the total eclipse of March 29 2006!

6. Total eclipse over Antarctica, November 23 2003. Satellite: Terra (upper right) en Aqua (above). Instrument: MODIS. Source: NASA/GSFC MODIS Land Rapid Response Team.

5. (above). Partial eclipse over Norh America, December 25 2000. Satellite: Terra (upper right) en Aqua (above). Instrument: MODIS. Source: NASA/GSFC MODIS Land Rapid Response Team.

7. (upper right) Niger en Chad during the annular eclipse of October 3 2005. Please compare the colours and shades with the normal situation (figure 8). Satellite: Terra (upper right) en Aqua (above). Instrument: MODIS. Source: NASA/GSFC MODIS Land Rapid Response Team.

8. (lower right. Same area as figure 7 under normal conditions. Date: September 28 2005. Satellite: Terra (upper right) en Aqua (above). Instrument: MODIS. Source: NASA/GSFC MODIS Land Rapid Response Team.

• Asteroid
• Actinoform cloud patterns
• Bénard cells
• Cloud streets
• Colour of the ocean
• Contrails
• Disturbances in cold air; polar low
• Disturbances in warm air; thunder
• Dust
• Fog over Northsea
• Hurricanes
• Glory
• Lake effect snow
• Low pressure system
• Mountain waves

• Internal (ocean) waves
• Kármàn vortices
  
• Lunar eclipse
• Oil spills
• Red tide
• Ship trails
• Snow
• Sunglint
• Tropical cyclones
• Volcanic ash
• Volcanic eruptions
• Wake vortices
  
• Wild fires

Very high resolution satellite images of all these phenomena and detailed explanation (in Dutch) can be found in: Het weer op satellietbeelden (Weather on satellite imagery), Uitgeverij Elmar, Rijswijk (The Netherlands) 2005.