What is that all about? Basically, in a nutshell, every day the heat of the sun varies all over the Earth. Because of unequal solar heating, temperatures vary over the entire globe; the air at the equator is much warmer than at the poles.
So the warm, light air rises and spreads toward the poles and the colder, heavier air sinks toward the equator. But we live on a planet that rotates, so this simple wind pattern is distorted to such a degree that the air is twisted to the right of its direction of motion in the Northern Hemisphere and to the left in the Southern Hemisphere. Today we know this effect as the Coriolis Force and as a direct consequence, great wind spirals are produced which we know as high and low pressure systems.
In the Northern Hemisphere, the air in low pressure areas spirals counterclockwise and inward — hurricanes, for instance, are Coriolis mechanisms, circulating air counterclockwise. In contrast, high pressure systems the air spirals clockwise and outward from the center. In the Southern Hemisphere the direction of the spiraling of the air is reversed. So why do we generally associate high pressure with fair weather and low pressure with unsettled weather?
Since cool air has less of a capacity to hold water vapor as opposed to warm air, clouds and precipitation are caused by cooling the air. Any droplets that might lead to the formation of clouds would tend to evaporate. The end result tends to be a clearer and drier environment. Conversely, if we decrease the air pressure, the air tends to rise into the higher levels of atmosphere where temperatures are colder.
What makes the wind blow? Find out More. What is Peer Pressure? What is Humidity? Water in the Air! I have an excuse for you. Blame it on the atmospheric pressure. If something floats, it's supposed to be lighter than a feather.
But the atmosphere is floating and there's nothing feathery about it: Ten to twenty tons of atmosphere rest on the average adult. Why don't we collapse under such pressure? Fortunately, our bodies exert from within an equal pressure to the atmosphere.
So 10 tons of air may be resting on you, but another 10 tons are pushing outward from inside your body. Nobody really collapses and hardly anyone is even aware of the heavy air. But if you had an operation, an injury, or maybe a connective-tissue disease such as arthritis , your body might not be in exact, natural balance with the surroundings.
You really can feel it when the pressure changes within the atmosphere. The following figure shows that balance. The boiling point of water is a function of pressure. At the surface, water boils at degrees Fahrenheit. But at , feet, water boils at only 40 degrees. The atmosphere itself is very sensitive to its own variations.
A slight change? Because the atmosphere consists of a group of gases, it must have some weight. The following chart shows the composition of the atmosphere? There's just the right mix of oxygen and nitrogen to support life and achieving that mix was no easy matter. If the earth were closer to the sun, the intense heat would cause the gases to escape? On Venus, the temperature is as high as degrees. Mercury has an average temperature of degrees.
Migraine attacks are thought to be triggered by environmental or biological changes, and that includes changing atmospheric pressure. Cynthia Armand explains, "Our head is made up of pockets of air that we call sinuses. Usually, those pockets of air are at equilibrium with the atmospheric pressure. When there's a change in that atmospheric pressure, it creates a change in what you're experiencing in your head and what's going on in the air around you. That shift is a Migraine trigger.
The temperature changes that tend to come with changing barometric pressure are another Migraine trigger. If the changing barometric pressure comes with a lightning storm, the chances of it triggering a Migraine attack are even greater. Vince Martin explained his fascinating research linking Migraine and lightning:.
How can the barometric pressure today affect your blood pressure? Your circulatory system is made up of your heart , which acts as a pump, and your arteries and veins, which carry blood to and from your heart and tissues.
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