Where do the westerlies and polar easterlies meet

In what stormy region do the westerlies and polar easterlies converge

where do the westerlies and polar easterlies meet

The polar easterlies are the dry, cold prevailing winds that blow from the Unlike the westerlies in the middle latitudes, the polar easterlies are. The westerlies, anti-trades, or prevailing westerlies, are prevailing winds from the west toward If the Earth were a non-rotating planet, solar heating would cause winds Throughout the year, the westerlies vary in strength with the polar cyclone. Polar easterlies · West wind · Ferrel cell · Trade winds · Ocean currents. You would observe that the wind moving from the equator to the north pole was . polar easterlies meet warm prevailing westerlies, the polar jet stream exists.

As the cyclone reaches its maximum intensity in winterthe westerlies increase in strength. As the cyclone reaches its weakest intensity in summerthe Westerlies weaken. In the Southern hemisphere, because of the stormy and cloudy conditions, it is usual to refer to the westerlies as the roaring forties, furious fifties, or shrieking sixties according to the varying degrees of latitude.


The currents in the Northern Hemisphere are weaker than those in the Southern Hemisphere due to the differences in strength between the westerlies of each hemisphere. Ships crossing both oceans have taken advantage of the ocean currents for centuries. The ACC is the dominant circulation feature of the Southern Ocean and, at approximately Sverdrupsthe largest ocean current. Extratropical cyclones[ edit ] A fictitious synoptic chart of an extratropical cyclone affecting the UK and Ireland.

The blue arrows between isobars indicate the direction of the wind, while the "L" symbol denotes the centre of the "low". Note the occluded, cold and warm frontal boundaries. Extratropical cyclone An extratropical cyclone is a synoptic scale low pressure weather system that has neither tropical nor polar characteristics, being connected with fronts and horizontal gradients in temperature and dew point otherwise known as "baroclinic zones".

Here are two examples of air flow caused by pressure gradient. When a can of coffee is "vacuum packed," air is removed from the can. When the canis opened you can hear air rush in from the outside higher pressure. Similarly, when you blow up a balloon you create a high pressure area because you compress the air and increase its density within the balloon. When the balloon is punctured the air rushes outward to the lower pressure.

In both examples air moves from higher to lower pressure, and the greater the difference the faster the air travels.

where do the westerlies and polar easterlies meet

Global Winds Once the air has begun to move surplus heat to the poles and surplus cold to the equator another force comes into play. This is called the Coriolis force, and is caused by the rotation of the earth. Imagine yourself in a fixed position in space, looking down at the earth. You would observe that the wind moving from the equator to the north pole was traveling in a straight line, with the earth's rotating surface moving beneath it.

Now place yourself at a location on the earth's surface and observe the wind again. The wind would appear to be curving to the right. The earth rotates on its axis at the rate of miles per hour at the equator.

where do the westerlies and polar easterlies meet

The speed decreases with increasing latitude until it is virtually zero at the poles. This is because the latitude circles grow smaller. Place an object on the equator and allow 24 hours to go by. When the object returns, it will have traveled more than 24, miles - in other words, to travel that distance in 24 hours its linear speed was mph. Now place the object at 60 degrees north and let it make its circle. In 24 hours it will travel about 12, miles at mph. At the north pole the linear speed would be zero because there would be no distance traveled.

As an object such as a piece of wind, or a rocket starts to move in a straight path from the equator to the north pole, its eastward speed the earth rotates from west to east will be mph. As it travels northward, its eastward movement will be faster than the eastward movement of the surface of the earth at higher latitudes. It will run ahead of any object at higher latitudes, and appear to an earth based observer to be curving to the right.

where do the westerlies and polar easterlies meet

Similarly, if the object traveled from the north pole to the equator it would have no eastward movement, and would fall behind a lower latitude object whose eastward movement would be faster. To an earth based observer the curve would again appear to be to the right of the direction of motion.

Why is it, then, that in the southern hemisphere this apparent motion is reversed - that is, the Coriolis deflection is to the left? Imagine yourself once again in space. This time you are hovering just above the north pole. When you look down at the rotation of the earth you see it moving counterclockwise.

Now relocate yourself to just above the south pole.

GKites: Wind Origins

When you glance down, the earth is rotating clockwise. This explains why the apparent curve is to the right in the northern hemisphere and to the left in the southern. In fact, as we continue to study wind motion, we'll see that each hemisphere is a mirror image of the other.

where do the westerlies and polar easterlies meet

Now one more imaginary placement of yourself. If you straddled the equator you would see neither clockwise or counterclockwise movement.

where do the westerlies and polar easterlies meet

Because of this, the Coriolis force is not in effect at the equator. General Wind Patterns Local wind patterns are the result of pressure differences in the immediate area: But there are global patterns that we can observe as well. Let's start by following movement in the northern hemisphere. Hot air rises from the equator, creates a low pressure area, and flows towards the north pole.

The upper wind flow is deflected to the right by the Coriolis effect, which causes it to pile up and move from west to east. The piled up air cools, creating a high pressure area, and sinks; and as it accumulates on the surface it flows towards both the equator and north pole. The air moving toward the equator is influenced by the Coriolis effect and moves from the northeast, and because of its direction is called the northeast trade winds.

Wind is classified according to the direction from which it is blowing. The poleward moving air also moves to the right and is called the prevailing westerlies. The third wind belt develops as cold polar air sinks and moves south, is deflected to the right, and is therefore called the polar easterlies.