Wind essentials Flashcards
What is Earths atmospheric circulation driven by?
Driven by the imbalance between equatorial energy surpluses and polar energy deficits, Earth’s atmospheric circulation transfers both energy and mass on a grand scale, determining Earth’s weather patterns and the flow of ocean currents.
What is the dominant medium for redistributing energy. Where dose this occure?
The atmosphere is the dominant medium for redistributing energy from about 35° latitude to the poles in each hemisphere, whereas ocean currents redistribute more heat in a zone straddling the equator between the 17th parallels in each hemisphere
What redistributes heat in a zone straddling the equator?
Ocean currents redistribute more heat in a zone straddling the equator between the 17th parallels in each hemisphere.
What is Air Pressure?
Pressure produced by the motion, size, and number of gas molecules in the air and exerted on surfaces in contact with the air; an average force at sea level of 1 kg · cm−3. Normal sea-level pressure, as measured by the height of a column of mercury (Hg), is expressed as 1013.2 millibars, 760 mm of Hg, or 29.92 inches of Hg. Air pressure can be measured with mercury or aneroid barometers.
What is “thin air”?
The subjective experience of “thin air” at altitude is caused by the smaller amount of oxygen available to inhale. Mountaineers feel the effects of thin air as headaches, shortness of breath, and disorientation as less oxygen reaches their brain—these are the symptoms of acute mountain sickness
Why is warmer air less dense or lighter than colder air?
When air in the atmosphere is heated, molecular activity increases and temperature rises. With increased activity, the spacing between molecules increases so that density is reduced and air pressure decreases. Therefore, warmer air is less dense, or lighter, than colder air, and exerts less pressure.
How dose water vapor in the air effect density?
Moist air is lighter because the molecular weight of water is less than that of the molecules making up dry air. If the same total number of molecules has a higher percentage of water vapour, mass will be less than if the air were dry (that is, than if it were made up entirely of oxygen and nitrogen molecules). As water vapour in the air increases, density decreases, so humid air exerts less pressure than dry air.
Is humid/cold dry air associated with high/low pressure?
humid air is associated with low pressure and cold, dry air is associated with high pressure.
What is a Barometer?
Any instrument that measures air pressure is a barometer
What is a Mercury Barometer?
A device that measures air pressure using a column of mercury in a tube; one end of the tube is sealed, and the other end is inserted in an open vessel of mercury.
What is an Aneroid barometer?
A device that measures air pressure using a partially evacuated, sealed cell.
Imagine a small chamber, partially emptied of air, which is sealed and connected to a mechanism attached to a needle on a dial. As the air pressure outside the chamber increases, it presses inward on the chamber; as the outside air pressure decreases, it relieves the pressure on the chamber—in both cases causing changes in the chamber that move the needle.
What is barometric pressure?
To compare pressure conditions from one place to another, pressure measurements are adjusted to a standard of normal sea-level pressure, which is 1013.2 mb. In Canada and certain other countries, normal sea-level pressure is expressed as 101.32 kilopascals, or kPa (1 kPa = 10 mb). The adjusted pressure is known as barometric pressure.
What is Wind?
The horizontal movement of air relative to Earth’s surface; produced essentially by air pressure differences from place to place; turbulence, wind updrafts and downdrafts, adds a vertical component; its direction is influenced by the Coriolis force and surface friction.
What are the two principle properties of Wind?
Wind’s two principal properties are speed and direction, and instruments measure each
What is an Anemometer?
An anemometer measures wind speed in kilometres per hour (km·h−1), miles per hour (mph), metres per second (m·s−1), or knots.
