Winter
2007 Schools Wikipedia Selection. Related subjects: Climate and the Weather
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Winter is one of the four seasons of temperate zones. It is the season with the shortest days and the lowest temperatures. In areas further away from the equator, winter is often marked by snow.
Depending on place and culture, what is considered to be the start and end of winter vary. Contemporary meteorology takes winter to be the months of December, January, and February in the Northern Hemisphere and June, July, and August in the Southern Hemisphere. However, many cultures in Europe and East Asia consider winter to begin in November.
Meteorological aspects
Meteorological winter is the season having the shortest days (which vary greatly according to latitude) and the lowest temperatures. Nighttime predominates the winter season, and in some regions it has the highest rate of precipitation as well as prolonged dampness due to permanent snow cover in such areas. Measured astronomically, winter begins on the shortest day of the year, and each day of winter has more sunlight than the previous one.
Outside the equatorial areas, winter is cold and (particularly in the Northern Hemisphere) snowy. Blizzards often develop and cause many transportation delays. A rare meteorological phenomenon encountered during winter is ice fog, which is composed of ice crystals suspended in the air and happening only at very low temperatures, below about −30 °C .
Time period of winter
Astronomically, it starts with the winter solstice (around December 21 in the Northern Hemisphere and June 21 in the Southern Hemisphere), and ends with the spring equinox (around March 21 in the Northern Hemisphere and September 21 in the Southern Hemisphere). In meteorology, it is by convention counted instead as the whole months of June, July and August in the Southern Hemisphere and December, January and February in the Northern Hemisphere.
However, in the United Kingdom and Ireland the winter solstice is traditionally considered as midwinter, the winter season beginning November 1 on All Hallows or Samhain. Winter ends and spring begins on Imbolc or Candlemas, which is February 1 or 2. This system of seasons is based on the length of days exclusively. The three-month period of the shortest days and weakest solar radiation occurs during November, December and January in the Northern Hemisphere (May-July in the Southern).
In Chinese astronomy (and other East Asian calendars), winter is taken to commence on or around November 7, with the Jiéqì known as (立冬 lì dōng, literally "establishment of winter".)
In reality, the three-month period associated with the coldest average temperatures typically begins somewhere in late November or early December in the Northern Hemisphere. If "winter" is defined as the statistically coldest quarter of the year, then the astronomical definition is too late by almost all local climate standards, and the traditional English/Irish definition of November 1 (May 1 in the Southern Hemisphere) is almost always too early to fit this standard. No matter the recogning, winter is the only season that spans two calendar years in the northern hemisphere. (In other words, there are very few temperate climates in which the vernal equinox is on average colder than the winter solstice, and very few temperate climates in which Samhain is colder than Imbolc)
What causes winter
The tilt of the earth's axis relative to its orbital plane has a dramatic effect on the weather. The popular belief that winter is caused by the Earth being farther from the Sun than in summer is not true. In fact, in the Northern Hemisphere, winter occurs when the Earth is its closest to the Sun.
The earth is tilted at an angle of 23°27' (23 degrees 27 minutes) to the plane of its orbit, and this causes different latitudes on the Earth to directly face the Sun as the Earth moves through its orbit. It is this variation that primarily brings about the seasons. When it is winter in the Northern Hemisphere, the Southern Hemisphere faces the Sun more directly and thus experiences warmer temperatures than the Northern Hemisphere.
During winter in either hemisphere, sunlight hits that hemisphere at an oblique angle. In regions experiencing winter, the same amount of solar radiation is spread out over a larger area (see Effect of sun angle on climate). This effect is compounded by the larger distance that the light must travel through the atmosphere, allowing the atmosphere to dissipate more of this already limited heat.
Ecology
Animals
To survive the harshness of winter, many animals have developed different behavioural and morphological adaptations:
- Migration is a common effect of winter upon animals, notably birds. However some birds, the cardinal for example, do not migrate.
- Hibernation is a state of reduced metabolic activity during the winter. These animals "sleep" during winter and only come out as warm weather returns. For example, gophers, bears, frogs, snakes and bats hibernate.
- Some animals store food for the winter and live upon it instead of hibernating completely. This is the case of squirrels, beavers, skunks, badgers and raccoons.
- Resistance is observed when an animal endures winter, but changes in ways such as colour and musculature. The colour of the fur or plumage are changed to white in order to be confused with snow and thus, to retain their cryptic coloration year round. Examples are the ptarmigan, the arctic fox, the weasel, the white-tailed jack rabbit or the mountain hare.
- Some fur-coated mammals grow a heavier fur coat during the winter. This improves the heat-retention qualities of the fur. The coat is then shed following the winter season to allow better cooling. The heavier winter coat made this season a favorite for trappers who sought more profitable skins.
- Snow also affects the ways animals behave, as many take advantage of the insulating properties of snow by burrowing in it. Mice and voles typically live under the snow layer.
Plants
Annual plants never survive the winter. As for perennial plants, many small ones profit from the insulating effects of snow by being buried in it. Larger plants, particularly deciduous trees, usually let their upper part die, but their roots are still protected by the snow layer. Few plants bloom in the winter, though exceptions include the flowering apricot (which flowers in time for Chinese New Year).
Activities
Snow activities
- Bobsledding - a winter sport in which teams make timed runs down narrow, twisting, banked purpose-built iced tracks in a gravity-powered, steerable sled.
- Skiing - the activity of gliding over snow using what is now fibreglass planks called skis that are strapped to the skiers' feet with ski bindings.
- Sledding - a downhill activity where the user uses a sled to glide down the hill.
- Snowball fight - a physical game in which snowballs are thrown with the intention of hitting someone else.
- Snowboarding - an increasingly common sport where participants strap a composite board to their feet and slide down a snow-covered mountain.
- Snowshoeing - a means of travel in which one is able to walk on top of the snow by increasing the surface area of their feet.
- Snowman building - creating a man-like model out of snow.
- Building snow castles and other snow constructions - The SnowCastle of Kemi is the largest one in the world.
Ice activities
- Ice skating - a means of traveling on ice with skates, narrow (and sometimes parabolic) blade-like devices moulded into special boots (or, more primitively, without boots, tied to regular footwear).
- Ice boating - a means of travel in a specialized boat similar in appearance to a sailboat but fitted with skis or runners (skates) and designed to run over ice instead of (liquid) water.
- Ice biking - The continuation of regular cycling activities in the winter and cold weather.
- Ice fishing - the sport of catching fish with lines and hooks through an opening in the ice on a frozen body of water.
- Ice diving - a type of penetration diving where the dive takes place under ice.
- Ice sculpture - elaborate sculptures are carved out of blocks of ice.
- Ice Hockey - A team sport played on the ice with skates, sticks and a puck. The goal is to send the puck in the adverary team's net more often than they send it in yours during 60 minutes of play.
- Curling - A team sport using skates, brooms and stones. The object of the game is to slide your stones in a bullseye and get your opponent's stones out of it.
- Ice climbing - The recreational activity of climbing ice formations such as icefalls, and great frozen waterfalls.
Psychology
Passing seasons change the habits and moods of people. Around November and December in the northern hemisphere, a gloominess nicknamed "winter blues", "February blahs", "Holiday depression", or doldrums, is informally noted amongst people. The severest cases of this type of depression is diagnosed as seasonal affective disorder (SAD). Symptoms include sleeping more, tiredness, depression, and physical aches. Although causes include genetic disposition and stress, the prevailing environmental influence is decreased exposure to light due to winter weather patterns and the increased amount of clothing that must be worn to keep warm.
The symbolism of winter
Winter is highly symbolic of many things to many people and has been used to represent various things by artists in all media. Some use winter to suggest death, as in Robert Frost's " Stopping by Woods on a Snowy Evening". Some use it to suggest the absence of hope, as in C. S. Lewis's The Lion, the Witch and the Wardrobe, where it was always winter but never Christmas. Winter is one concerto in Vivaldi's "The Four Seasons"; and there are many examples of four paintings, all showing the same scene in different seasons. Ursula K. LeGuin's novel The Left Hand of Darkness is set on a planet named Winter. In Alex Raymond's comic strip, Flash Gordon, there is a land called Frigia, where it is always winter. The land of Frigia is also featured in the serial Flash Gordon Conquers the Universe. Other uses of winter in the graphic arts occur in Winsor McCay's Little Nemo in Slumberland. There are many films in which a winter setting plays an important role, Fargo being an example. In addition to this, novels such as Ethan Frome also use a winter setting to mirror the bleak, frozen feelings that the characters harbour.
Mythological explanations of winter
In Greek mythology, Hades kidnapped Persephone to be his wife. Zeus ordered Hades to return her to Demeter, the goddess of the earth and her mother. However, Hades tricked Persephone into eating the food of the dead so Zeus decreed Persephone would spend six months with Demeter and six months with Hades. During the time when her daughter is with Hades, Demeter becomes depressed and causes winter.
Personifications of winter
- Old Man Winter
- Father Winter
- Jack Frost
- Ded Moroz
- Snegurochka
 An allegory of Winter, by Ambrogio Lorenzetti |
 Winter, by Giuseppe Arcimboldo |
 19th century cartoon of Jack Frost as a United States major-general during the American Civil War |
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 A depiction of Snegurochka by Victor Vasnetsov |
Exceptional winters
- 1816 is considered the " Year Without a Summer" because the summer was so cold that it was like winter lasted all year.
- Russian Winters of 1812/13 and 1941/42
- In Europe, the winters of 1962/63 and 1981/82 were abnormally cold.
- The Winter of Discontent is the name for the British winter of 1978-79, during which there were widespread strikes. Lorry drivers, train drivers, nurses, most public sector employees, refuse collectors, and workers at Ford Motors all went on strike. Most notorious however was an unofficial strike by gravediggers.