Air Pressure, Weather Systems, and Storms: Key Concepts in Meteorology

What is air pressure?

The weight of air molecules acting as a force upon the Earth, averaging 1013.25 mb at sea level.

How does high pressure affect weather conditions?

High pressure results in little cloud formation, low precipitation, and cold, dry temperatures.

What are the characteristics of low pressure?

Low pressure is associated with higher temperatures, higher humidity, more water vapor, and faster wind speeds, often leading to bad weather.

What is the relationship between temperature and air density?

Colder temperatures result in more dense and closely packed air particles, leading to higher air pressure.

What are the three temperature scales?

Fahrenheit, Celsius, and Kelvin.

What is absolute zero?

0 degrees Kelvin, the point at which all particle motion stops.

What is conduction in heat transfer?

The transfer of heat from molecule to molecule within a substance, always moving from warm to cool.

How does convection transfer heat?

By mass circulation, where warm air rises and cold air sinks.

What is radiation in the context of heat transfer?

Energy from the sun traveling in the form of waves.

What is latent heat?

The heat energy required to change the state of a substance.

What happens during evaporation?

It is a cooling process due to the absorption of latent heat.

What occurs during condensation?

It is a warming process due to the release of latent heat.

What is relative humidity?

A measure of the total amount of water vapor the air can hold based on temperature.

What is absolute humidity?

The percentage of the atmosphere that is made up of water vapor, typically ranging from 0-4%.

What are the main components of the atmosphere?

75% nitrogen, 20% oxygen, and 1% argon.

What is the troposphere?

The lowest layer of the atmosphere, extending from 0-7 miles, where weather occurs and clouds form.

What is the stratosphere known for?

Extending from 7-30 miles, it contains the ozone layer that warms this layer.

What occurs in the mesosphere?

Extending from 30-50 miles, it is where molecules break up and it is the coldest layer.

What is the thermosphere?

The layer above the mesosphere, extending from 50 miles and higher, where auroras occur and low Earth orbit satellites are found.

What drives wind at the surface level?

Horizontal differences in air pressure, where air moves from high to low pressure.

What is an isobar map?

A map that shows surface pressure.

What is the pressure gradient force?

The force that causes air to move from high to low pressure, with greater differences resulting in faster air movement.

How does the Coriolis force affect wind direction?

It deflects moving air to the right in the northern hemisphere and to the left in the southern hemisphere.

What effect does friction have on wind?

It slows air at the surface as it encounters obstacles, affecting wind speed and direction.

How do precipitation patterns relate to air pressure?

Rain occurs where air rises (low pressure) and less rain occurs where air sinks (high pressure).

What is an air mass?

An extremely large body of air characterized by similar temperature and humidity.

What are the classifications of air masses based on temperature and humidity?

Maritime (M), Continental (C), Tropical (T), Polar (P), Arctic (A).

What characterizes a cold front?

Cold, dry stable air replaces warm, moist unstable air, leading to vertical cloud development and thunderstorms.

What is a warm front?

Warm, moist, unstable air overrides cold, dry, stable air, resulting in horizontal cloud development and steady rain.

What is a stationary front?

A front with no motion where winds are parallel but in opposite directions.

What is an occluded front?

A cold front overtakes a warm front, sealing off the warm sector and preventing storm strengthening.

What are cyclones and anticyclones?

Low and high-pressure systems whose rotation depends on the hemisphere in which they are found.

What is a mid-latitude cyclone?

A cyclone that forms and moves along the boundary between polar air and warmer southern air, often associated with occluded fronts.

What is a thunderstorm?

A storm with thunder and lightning, typically accompanied by heavy rain or hail, and can spawn tornadoes.

Where are thunderstorms most frequently distributed in the United States?

Florida, the Gulf Coast, and Central Plains.

What is lightning?

A discharge of electricity in mature storms, primarily occurring within the cloud.

What is the difference between cloud-to-cloud and cloud-to-ground lightning?

Cloud-to-cloud lightning accounts for 80% of lightning, while cloud-to-ground lightning accounts for 20%.

What are the stages of air mass thunderstorms?

Cumulus, Mature (Cumulonimbus), and Dissipating.

What characterizes supercell thunderstorms?

A large, long-lasting thunderstorm with a single rotating updraft (mesocyclone) formed due to shear winds.

What is a tornado?

A rapidly rotating column of air that blows around a small area of intense low pressure, reaching the ground.

What is the Fujita Scale?

A scale based on the damage created by a storm, ranging from F0 (weakest) to F5 (strongest).

What is the primary difference between mid-latitude and tropical cyclones?

Mid-latitude cyclones derive energy from horizontal temperature variations, while tropical cyclones derive energy from warm water and latent heat from condensation.

What conditions are necessary for the formation of tropical cyclones?

Surface convergence, little to no wind shear, and sea surface temperatures of at least 80°F.

What is the Saffir-Simpson scale used for?

Classifying tropical cyclones based on sustained wind speed.

What happens to a hurricane when it moves over cold water or land?

It weakens due to loss of warm water energy and increased shear winds.

What are the damaging aspects of hurricanes?

Highest winds on the eastern side, storm surge on the north side, and tornadoes spawned from outer thunderstorms.

What is the historical naming convention for hurricanes?

Initially based on location, later alternating between female and male names.

What was Hurricane Katrina's classification at its strongest?

Category 5 hurricane.

What is the significance of the Coriolis Effect in hurricane formation?

Hurricanes seldom form within 5 degrees of the equator and never cross it.

What is the tilt of Earth's rotational axis?

23.5 degrees from being perpendicular to Earth's orbital plane.

How long does it take for Earth to complete one full orbit around the Sun?

365.242 days.

What phenomenon causes the seasons on Earth?

The alternating direct light received by the northern and southern hemispheres.

When does the Vernal Equinox occur?

March 20th.

What is the solar angle at the Summer Solstice?

83 degrees south.

What is the solar angle at the Winter Solstice?

37 degrees south.

What are Milankovitch Cycles?

Long-term Earth motions affecting climate over periods of 10,000 to 100,000 years.

What is precession in relation to Earth's motion?

Changes in the orientation of Earth's axial tilt, taking approximately 22,000 years for a full cycle.

What does obliquity refer to?

Changes in the angle of Earth's axial tilt, ranging from 22 degrees to 24.5 degrees, with a full cycle taking about 40,000 years.

What is eccentricity in Earth's orbit?

Changes in the shape of Earth's orbit from more to less elliptical, taking about 100,000 years for a full cycle.

What is the difference between weather and climate?

Weather refers to short-term atmospheric conditions, while climate describes long-term atmospheric behavior.

How do isotopic ratios help determine past climates?

They indicate rates of evaporation and temperature based on rocks and ice from the past.

What natural event can cause climate change through volcanic activity?

Volcanic explosions can eject greenhouse gases into the atmosphere, raising temperatures.

What is one effect of aerosols in the atmosphere?

They reflect sunlight and can lead to localized cooling.

What is a feedback mechanism related to water vapor?

Higher temperatures lead to more evaporation, which increases water vapor in the atmosphere.

What has been the increase in average global surface temperature since the early 20th century?

0.8 degrees Celsius.

What are some atmospheric impacts of global warming?

Increased evaporation, changes in precipitation patterns, and alterations to cyclonic storms.

What happens to continental ice due to rising atmospheric temperatures?

There is a loss of continental ice and melting of sea ice.

How does deforestation contribute to climate change?

It adds CO2 to the atmosphere and reduces photosynthesis.