Chat with AIExam 8: Air Pressure and Winds
On an upper-level 500-mb map the winds tend to parallel the contour lines in a wavy west-to-east direction,and the contour lines tend to decrease in height from south to north.Explain.
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VerifiedThe combination of the pressure gradient force and Coriolis force cause winds to flow in a west to east pattern.The decrease in contour line height from south to north is the result of air at this level being warmer in the south and colder in the north.On maps,where horizontal temperature contrasts are large there is also a large height gradient-the contour lines are close together and the winds are strong.Where the horizontal temperature contrasts are small,there is a small height gradient-the contour lines are spaced farther apart and the winds are weaker.In general,on maps such as this we find stronger north-to-south temperature contrasts in winter than in summer,which is why the winds aloft are usually stronger in winter.
The pressure announced on last night's television weather broadcast was 29.92.Explain how this was measured and give the units.Would this be considered an unusually large or low pressure value?
(91) Verified"29.92" stands for 29.92 inches of mercury (in.Hg),which is equivalent to 1013.25 mb and 76 cm.It's the pressure found at sea level,which is also called standard atmospheric pressure.
The barometer used to obtain this pressure reading was a mercury barometer.Evangelista Torricelli,a student of Galileo,invented the mercury barometer in 1643.His barometer,similar to those in use today,consisted of a long glass tube open at one end and closed at the other.Removing air from the tube and covering the open end,Torricelli immersed the lower portion into a dish of mercury.He removed the cover,and the mercury rose up the tube to nearly 76 cm (or about 30 in.)above the level in the dish.Torricelli correctly concluded that the column of mercury in the tube was balancing the weight of the air above the dish,and hence its height was a measure of atmospheric pressure.Mercury barometers are still used today in many settings,although they are no longer manufactured or sold in Europe because of restrictions on the use of mercury.
The ____ force is an apparent force created by Earth's rotation.
(79) VerifiedB
In middle latitudes,when an area of high pressure approaches a city,surface pressure usually ____.When it moves away,pressure usually ____.
(87) A rapid change in pressure over a relatively short distance is called a ____ pressure gradient.
(73) A pascal (Pa)is the force of ____ acting on a surface area of ____.
(82) Why do daily pressure fluctuations occur,and where on Earth can you find significant daily fluctuations?
(96) A geostrophic wind is a wind that results from a balance between the ____ force and the ____ force.
(91) On an upper-level chart cold air aloft is generally associated with ____________________ pressure.
(81) The surface pressures at the bases of warm and cold columns of air are equal.Air pressure in the warm column of air will ____ with increasing height ____ in the cold column.
(77) The angle at which surface winds cross isobars depends upon surface friction,wind speed,and the height above the surface.
(71) Upper-level winds in the middle latitudes of both hemispheres generally blow from ____.
(80) In an aneroid barometer,a general rule is that the higher the reading,the more likely ____ weather will occur,and the lower the reading,the better the chances are for ____ weather.
(71) The unit of pressure designated by the International System (SI)of measurement is the ____.
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