What is atmospheric pressure and how is it measured?

Atmospheric pressure is the weight of a column of air contained in a unit area from mean sea level to the top of the atmosphere, expressed in units of millibar. It is measured using a mercury barometer or an aneroid barometer.

Fill in the blank: The average atmospheric pressure at sea level is ___ milibar.

1,013.2 milibar.

True or False: The pressure in the atmosphere increases with height.

False. The pressure decreases with height in the atmosphere.

What is the primary cause of air motion, or wind, in the atmosphere?

The primary cause of air motion is the variation in atmospheric pressure, where air moves from high pressure areas to low pressure areas.

The vertical pressure gradient force is generally balanced by which other force?

The vertical pressure gradient force is generally balanced by a nearly equal but opposite gravitational force.

Fill in the blanks: In the lower atmosphere, the pressure decreases rapidly with height, approximately ___ mb for each ___ m increase in elevation.

1 mb; 10 m.

What are isobars and what do they represent in the study of atmospheric pressure?

Isobars are lines connecting places having equal atmospheric pressure, and they are used to study the horizontal distribution of pressure in the atmosphere.

True or False: A low-pressure system is always enclosed by one or more isobars with the highest pressure in the center.

False. A low-pressure system is enclosed by one or more isobars with the lowest pressure in the center.

The area known as equatorial low is characterized by ___ sea level pressure.

Low

What is the primary force that causes wind to move from high pressure to low pressure?

Pressure gradient force

The pressure gradient is strongest when ___ are close together.

Isobars

Fill in the blank: Winds at the surface diverge from high pressure areas and converge at ___ pressure areas.

Low

What happens to the wind at the equator in relation to isobars?

The wind blows perpendicular to the isobars, and the low pressure gets filled instead of intensified.

Fill in the blank: The wind circulation around a low pressure area is called ___ circulation.

Cyclonic

The pattern of planetary winds is primarily influenced by the ___ and ___ of atmospheric heating.

Latitudinal variation and emergence of pressure belts

True or False: The Inter Tropical Convergence Zone (ITCZ) is characterized by descending air and high pressure.

False. The ITCZ is characterized by rising air and low pressure.

What is the Hadley Cell and where does it occur?

The Hadley Cell is a tropical atmospheric circulation cell where warm air rises at the ITCZ and sinks at about 30° N and S latitudes.

What are the primary effects of the El Niño phenomenon on global weather?

El Niño can cause heavy rainfall on the west coast of South America, droughts in Australia and India, and floods in China.

True or False: The Southern Oscillation is unrelated to the changes in atmospheric pressure associated with El Niño.

False. The Southern Oscillation is closely related to the pressure changes associated with El Niño.

Explain the role of ocean currents in the general atmospheric circulation.

Ocean currents are initiated by atmospheric winds, and they provide energy and water vapor to the atmosphere, influencing climate patterns.

Fill in the blank: The circulation cell in the middle latitudes is known as the ___ cell.

Ferrel

The seasonal wind patterns that change during monsoons in Southeast Asia are primarily influenced by ___ and ___.

Temperature differences and air movement