Question 1

It takes a larger column of cold, more-dense air to exert the same surface pressure as a taller column of warm, less-dense air.

Accepted Answer

False

Question 2

In the Northern Hemisphere, the average height of contour lines on an upper-level isobaric chart tends to decrease northward.

Accepted Answer

This is because, in the Northern Hemisphere, temperature generally decreases with latitude. Since colder air is denser, the pressure decreases more rapidly with altitude in colder regions. Therefore, at a given pressure level (e.g., 500 mb), the altitude is lower in the north where it's colder, leading to a decrease in the average height of contour lines on an upper-level isobaric chart as one moves northward.

Question 3

An altimeter measures altitude but is calibrated to indicate pressure.

Accepted Answer

False

Question 4

One atmosphere of pressure is equivalent to 760 torr of pressure.

Accepted Answer

One atmosphere (atm) of pressure is exactly equivalent to 760 torr (or mmHg), as both are units used to measure pressure.

Question 5

The angle at which surface winds cross isobars depends upon surface friction, wind speed, and the height above the surface.

Accepted Answer

The angle at which surface winds cross isobars is influenced by surface friction, which slows down the wind near the surface and causes it to cross isobars at an angle. Wind speed and the height above the surface also affect this angle due to changes in friction and the Coriolis effect.

Question 6

Surface winds that blow over the ocean are closer to being geostrophic than those that blow over land.

Accepted Answer

Surface winds over the ocean are closer to being geostrophic because there is less friction over water than over land, allowing the winds to align more closely with the pressure gradient and Coriolis force, which are the main factors in geostrophic flow.

Question 7

Flights from San Francisco to New York City take, on average, about 30 to 45 minutes less than the return flights.

Accepted Answer

This is due to the prevailing jet streams that flow from west to east across the United States, which can increase the airspeed of flights from San Francisco to New York City, making the trip shorter than the return flight against the wind.

Question 8

The pressure gradient force is non-existent at the equator.

Accepted Answer

The pressure gradient force exists globally, including at the equator, as it is the force that results from differences in atmospheric pressure across the Earth's surface, driving wind and weather patterns.

Question 9

In middle latitudes, surface pressure changes are primarily the result of large high- and low-pressure areas that move toward or away from a region.

Accepted Answer

In middle latitudes, the movement of large high- and low-pressure systems is the primary driver of changes in surface pressure, influencing weather patterns as these systems move toward or away from a region.

Question 10

Station pressure and sea-level pressure can never be the same value.

Accepted Answer

Station pressure can be the same as sea-level pressure if the station is located at sea level under certain atmospheric conditions.

Question 11

If you (in the Northern Hemisphere)stand with the wind aloft to your back, Buys Ballot's law states that lower pressure will be to your right and higher pressure to your left.

Accepted Answer

According to Buys Ballot's law, in the Northern Hemisphere, if you stand with your back to the wind, lower pressure will be on your left and higher pressure on your right.

Question 12

Newton's first law of motion states that an object at rest will remain at rest, and an object in motion will remain in motion (and travel at a constant velocity along a straight line)as long as no force is exerted on the object.

Accepted Answer

Newton's first law of motion, also known as the law of inertia, states exactly that: an object at rest stays at rest and an object in motion stays in motion with the same speed and in the same direction unless acted upon by an unbalanced force.

Question 13

The angle at which surface winds cross isobars is to a large degree dependent on the roughness of the terrain.

Accepted Answer

The angle at which surface winds cross isobars is influenced by the Coriolis effect and friction, with the latter being significantly affected by the roughness of the terrain. Rougher terrain increases friction, which can alter the angle at which wind crosses isobars.

Question 14

Most of the time, the atmosphere does not approximate hydrostatic equilibrium.

Accepted Answer

The atmosphere is generally in a state of hydrostatic equilibrium, where the downward gravitational force is balanced by the upward pressure gradient force, except during instances of severe weather or rapid atmospheric changes.

Question 15

In the tropics, daily (diurnal)fluctuations of pressure appear to be due primarily to the absorption of solar energy by ozone in the upper atmosphere and by water vapor in the lower atmosphere.

Accepted Answer

The diurnal pressure variations in the tropics are influenced by solar heating, which affects ozone in the upper atmosphere and water vapor in the lower atmosphere, causing pressure changes.

Question 16

Net convergence of air would cause surface pressure to ____ and net divergence would cause surface pressure to ____.

Accepted Answer

Net convergence of air at the surface leads to an accumulation of mass and thus an increase in surface pressure. Conversely, net divergence involves the outward movement of air from a region, leading to a decrease in mass and a subsequent decrease in surface pressure.

Question 17

The Coriolis force is the force that causes the wind to blow.

Accepted Answer

The Coriolis force is not a true force, but an apparent one that results from the Earth's rotation, affecting the direction of the wind and other moving objects, but it does not cause the wind to blow. Wind is primarily caused by differences in atmospheric pressure.

Question 18

Surface pressure is affected by the relationship between upper-level divergence and surface convergence.

Accepted Answer

Surface pressure is affected by the relationship between upper-level divergence and surface convergence because when there is divergence aloft (air spreading out above), it can lead to lower pressure at the surface as air rises to replace the diverging air. Conversely, convergence at the surface (air coming together) can lead to higher pressure as air is forced to rise, cooling and spreading out aloft. This interaction between upper-level and surface processes is fundamental in the development of weather systems.

Question 19

The pressure gradient force has a direct effect on horizontal wind movements.

Accepted Answer

The pressure gradient force, which results from differences in atmospheric pressure, is a primary driver of horizontal wind movements, causing air to move from areas of high pressure to areas of low pressure.

Question 20

Air pressure decreases with height more rapidly in warm air than in cold air.

Accepted Answer

Air pressure decreases with height more rapidly in cold air than in warm air because cold air is denser than warm air.

Quiz 8: Air Pressure and Winds