Winter Solstice

December 20, 2000


Provided by: Weather Satellite Images
Summary author: Jim Foster

The image above was taken yesterday, December 19, from the Insat satellite (Indian Satellite), approximately 22,000 miles above the equator over the Indian Ocean. Notice that the Southern Hemisphere is light all the way to Antarctica, at the bottom of the image, whereas, the Northern Hemisphere is much darker. The winter solstice will be reached on December 21, at 8:37 a.m. Eastern Standard Time, when the Sun will be positioned directly above the Tropic of Capricorn (23.5 degrees south latitude). Thus, the maximum amount of daylight is now being received in the Southern Hemisphere. The reverse is true in the Northern Hemisphere - it's now dark all day north of the Arctic Circle (66.5 degrees north latitude), and the mid-latitudes (40 degrees north latitude) are in darkness for 14 hours a day.

The dry monsoon is in place over India - note the cloudless skies. Also, the Intertropical Convergence Zone (ITZ), the wide band of clouds stretching from Sumatra across the Indian Ocean, north of Madagascar, is positioned somewhat beneath the Sun - south of the equator. At the equinoxes, it's positioned very close to the equator.

Although we consider the solstice to be the first day of winter, the Romans considered this mid-winter. The ancient Roman midwinter festival of Saturnalia began on this date when the life-giving Sun halted its southern descent and once more began its northward return. During the Saturnalia celebration, masters sometimes feasted with slaves and friends and family exchanged gifts.

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