Chapter 9: WeatherVocabulary

Topic 7 in Textbook/WorkbookPage 126

Assignment• Due Friday April 11th

• All 30 vocabulary words –Words and definitions are to be copied onto

loose leaf.• 7 Vocabulary Words illustrated– You may pick 7 of the vocabulary words to

explain using a picture. Typed vocab words & clip art pictures will not be accepted.This assignment will count as a test grade!

Example

Precipitation

VOCABULARY WORDS

Air MassA large body of air in the troposphere with similar characteristics of pressure, moisture, and temperature

Air Pressure GradientThe change in air pressure over a given area.

AnemometerA weather instrument used to measure wind speed.

Atmospheric, Barometric, or Air Pressure

• The weight of the overlying atmosphere pushing down on a given unit of area.

Atmospheric TransparencyHow transparent the atmosphere is to insolation; how easily can insolation pass through the air.

BarometerAn instrument used to measure air pressure

Cloud Cover• The fraction or percent of the total

sky at a location that is covered by clouds.

Cold Front• The interface of an advancing cold

air mass and a warmer air mass. 

Cyclone• A low-pressure portion of the

troposphere that has air moving towards its center. Rotates counterclockwise. Includes: hurricanes & tornadoes, also called a low.

Cyclonic stormA large type of low-pressure storm system formed in the mid-latitudes.

Dew PointThe temperature at which the air becomes saturated with water vapor and the relative humidity is 100%

FrontThe interface between two air masses of different characteristics.

HumidityThe water vapor in the atmosphere

IsobarAn isoline used on weather and climate maps that connect points of equal air pressure.

Jet Stream• A concentrated curving band of high

speed, easterly moving winds usually at the top of Earth’s troposphere.

MonsoonCyclic and extreme weather changes caused by the shifting wind and pressure belts. Common in southwest Asia

Occluded front• The boundary of opposing wedges of

cold air masses formed when a cold front overtakes a warm front, lifting the warm air mass of Earth’s surface, forming mid-latitude cyclones

Planetary wind beltEast-west zones on Earth where the wind blows from one direction much of the time. AKA prevailing winds.

Polar FrontAn ever-changing boundary between the colder air masses toward the poles and the warmer air masses toward the middle latitudes.

PrecipitationFalling liquid or solid water from clouds toward Earth’s surface.

ProbabilityThe chance of some environmental event, such as rain or an earthquake occurring.

PsychromotorAn instrument that is used to indirectly measure the amount of water vapor in the air, such as a sling psychrometer

RadarAn instrument that uses radio/microwave electromagnetic radiation to observe many weather features such as precipitation, tornadoes, and hurricanes

Relative humidityThe ratio of the amount of water vapor in the air to the maximum amount it can hold

Stationary FrontA weather condition in which the boundary between two air masses remains in the same position

Station ModelCities and other weather station sites on weather maps represented by circles, with symbols in and around each circle that indicate the many weather variables.

TroposphereThe part of the atmosphere immediately above Erath’s surface; where most weather changes occur.

VisibilityThe farthest distance at which one can see a prominent object at Earth’s surface with the naked eye; decreased by fog, air pollution, and precipitation.

Warm FrontThe boundary of an advancing warm air mass and a retreating wedge of a cooler air mass; characterized by a gentle slope, long periods of precipitation, and strato (layered) clouds.

Water VaporGaseous water in the atmosphere; also called moisture or steam.

Weather VariablesCondition of the atmosphere such as temperature, air pressure, wind, moisture conditions, cloud cover, precipitation, and storms.