So This Is Christmas

Merry Christmas is such an infectious feeling I like to feel that way all year around.

So if you are visiting just before Christmas, just after Christmas or even here on Christmas day I am sure you will find something of interest for you and in the spirit of Christmas.

It may be said that Christmas is no longer a celebration but this must be spoken by people that have never had trouble closing their eyes on Christmas Eve in an expectation of what maybe left for them on the carpet under the tree.

I continue to look forward to the surprise on my Grandchild's faces to this day at Christmas events.

Merry Christmas - Merry Christmas - Merry Christmas

Friday, February 11, 2011

To Predict Weather, Understand Air Pressure Patterns

By Albert Sperk


Weather is created by the different proximities of the Earth's surface to the sun as the Earth rotates on its axis and around on its orbit. This orbit follows a pattern which makes it possible to predict weather. The Earth is divided into latitudinal areas that have basically the same climates. These climate zones are the Arctic Circle, and Antarctic Circle, at 66.5 degrees north and south, and the Tropic of Cancer and Tropic of Capricorn at 23.5 degrees north and south. The weather isn't the same all of the time, but it follows patterns that make weather forecasts possible. The atmosphere is in constant motion, moving up and down, seeking equilibrium as molecules are heated up and cooled down. The grouping of these molecules cause large air masses, these masses create conditions that we call weather patterns.

The earth spins on its axis on a 23.5 degree angle and orbits the sun every 365 days. During this time, different parts of the Earth receive different levels of exposure to the sun and different climates result in these areas. The Earth is divided into latitudinal categories to give a general idea of what the basic climates at different points on the Earth are like. The equator is at the center of the Earth and 23.5 degrees out from either side are the tropical areas. This part of the Earth is hot all year round and the convection, or warm rising air, in this area causes a band of low pressure. With low pressure comes dense cloud cover and rain.

This very warm air continues upward into the tropopause, a boundary between the troposphere and stratosphere. The warm air spreads out to the poles the farthest away from the sun, where the air cools and sinks around the 30 degree north and south latitudinal marks. This sinking air causes high pressure, keeping clouds away and causing hot arid climates. These are the areas where deserts are found.

Where the air sinks, the air that is there also moves and creates trade winds. By the time the air meets the equator the movement stops and this windless area is called the doldrums, given their name by ancient sailors. This circulation of air cells was first tracked by the English scientist George Hadley in 1753 and these circulating cells have since been named Hadley cells. The air that circulates weakly between the 60 degree lines of latitude and the polar regions are called polar Hadley cells.

Some of the rising air continues on to create the polar fronts, falling at 60 degrees north and south. Warm air from these areas rises and moves to the equator and sinking at 30 degrees north and south. These patterns were first detailed by William Ferrel and now are called Ferrel cells.




About the Author:



No comments:

If You Are Unable To Be There But Want To Show You Love Them Then Send -