All The Different Weather Types
By Belfort Instrument | May 31, 2008
Author: Leroy K. Calstard
We know that if the atmosphere did not exist, the earth would go without weather. Imagine for a moment for argument’s sake that the earth has an atmosphere indeed, as it is today, though the sun is absent. Absence of sun would mean absence of weather and that is not only because a frozen solid form the atmosphere will take. Actually the interaction between heat of the sun and our atmosphere builds air masses, while circulation patterns appear due to that. Pressure differences motivate air movements and wind is the end result of the same.
As in case of other materials, the air in the earth’s atmosphere is built of molecules that move about incessantly. Greater is the air pressure where denser concentration of molecules is found. Since air molecules are governed by gravity, the greatest air pressure is found nearest the earth’s surface and with altitude that decreases. The atmospheric pressure at sea level is about 14 and a half pounds on each square inch about which are normally not much conscious.
If air pressure is measured in hectopascals or millibars, normal air pressure ranges from 980 to 1040 hectopascals while on local conditions that is very much dependent.
At different speeds these molecules incessantly move while the speeds depend on temperature, lower the temperature slower is the peed and for higher temperature faster is the speed. The molecules speed up as a mass of air is heated and that results in expansion of air. The density of the molecules decreases as expansion takes place and thereby the air mass becomes lighter. The air mass that has become lighter starts rising now. Convection is the term for the entire process.
All through the world convection is going on constantly in the atmosphere. However neither regular nor uniform is the process. It depends on many local factors whether convection will take place, and if it does at all, how much that will be.
As air rises it cools. Therefore in due course the rising warm air masses get cooled down and to the ground that its starts sinking back. With the rise of air, low pressure results. High pressure is the result where it is sinking. As equilibrium is the goal of atmosphere, air moves from high pressure areas to low pressure ones. Wind is this very movement of air. More the difference between the high pressure and low pressure zones, more forceful winds would be the result.
An elliptical orbit the earth or the third rock from the sun follows and to complete that the time it takes is one year. The time to complete one orbit marks stretch of the earth’s year. Since elliptical is the earth’s orbit, in certain parts of the year it really comes closer to the sun. However that does not cause seasons even though more solar heat the earth receives then.
The earth’s movement is not limited to its travel through space in its own orbit, but it spins also on its axis like a top. In every 24-hour one spin it completes. Alteration between day and night is caused by the earth’s rotation. Weather conditions differ between day and night as is reflected in high and low temperatures and the effect of that is felt on weather patterns too.
On its axis the planet earth is tilted about 23 degrees and that causes really the change of seasons. Due to tilting different parts of the earth come closer to the sun as around the sun the earth travels in its orbit. Therefore during certain parts of the year different parts of the earth receive different amounts of heat.
In December the Northern Hemisphere receives less light since the North Pole is tilted away from the sun then. Thus the days become shorter there while the temperatures go down.
But as the earth moves on its orbit, North Pole comes close to the sun due to earth’s tilt. Till June 21 it continues to come closer to the sun and then the summer reaches its maximum. On that very day the sun is just above the Tropic of Cancer. Around the sun the earth continues to move until December 21 when the winter reaches its peak and the cycle is complete.
Just opposite are the seasons in the Southern Hemisphere even though the same cycle it experiences. In December the Southern Hemisphere is the closest to the sun and therefore it is summertime there. Quite logically June21 is the date marked for winter peak in the Southern Hemisphere.
The middle and high latitudes only, i.e., above 23.5 degrees north and below 23.5 degrees south, enjoy four seasons precisely. Normally for the tropics only wet and dry seasons are the two seasonal variations.
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Thinking About The Weather When Packing
By Belfort Instrument | May 31, 2008
Author: Victor Epand
Generally when people are packing their luggage for their holiday they tend to do one of two things. Either under anticipate or over compensate.
As far as the first is concerned, under anticipating the kind of weather and climate conditions that you will face on your holiday can result in either an uncomfortable experience or an expensive one as you hurriedly purchase clothing that you really should have purchased earlier and taken with you. It is relatively easy to ensure that you are aware well in advance of the kind of weather conditions you are likely to experience in that location at that particular time of year.
The best people to talk to to get advice on the kind of weather conditions you are likely to experience on your planned trip are of course travel agents, although it is also possible to carry out research yourself online. There are an increasing number of sites dedicated to helping you plan for the anticipated weather conditions. You will be well advised to do either or both of these things.
The other problem is over compensating, particularly if you are planning on going somewhere that is quite cold. Of course going to a cold location generally requires you to take clothing which is bigger and bulkier than if you were just going to a warm beach location. In this case, you would be sensible to think carefully abut the kind of materials that you are taking, as well as how to pack them. Don’t just throw in every jumper and coat that you own, because this will only add to your problems in taking a vast quantity of luggage with you.
Remember that layering is warmer than one single item usually. It also increases the opportunity for variety once you are on holiday. Certain types of clothing, particularly windproof jackets and other coats, help to keep in the warmth by having material built into the padding which holds a great quantity of air. This air, being close to your body, builds up heat and retains the heat quite well, which is an advantage.
However, a disadvantage of such clothing is that it also takes up considerable room, and it is not helpful to have to carry about with you a large suitcase whose chief component is fresh air. One possible solution to this is to use one of the air compression systems that have become so popular in recent times.
This air compression system is effectively a large transparent bag into which bulky clothes can be placed, and using a small air pump, the excess air is drawn out. It is remarkable how much less space bulky clothes will take up.
So by wise and careful planning and research on the kind of weather you are likely to experience, and using sensible choices of clothes and possibly a solution such as air compression, you can save yourself quite a headache. Of course, it would also be very sensible to make sure you have some kind of backup so that if you intend on going to a warm location, you also take clothing in case you have an unexpectedly cold day. Similarly, planning on going to a cold location could present with you with a challenge if the sun happens to come out, and all you have to wear are your thermals.
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