Chapter 7

Question 1

weight

Answer 1

A measure of the force of gravity acting on an object with mass

Question 2

gravity

Answer 2

Is the natural process where any body of mass found in the universe attracts other nearby bodies with a force proportional to the product of their masses and inversely proportional to the distance that separates them. First proposed by Sir Isaac Newton in 1686

Question 3

atmospheric pressure

Answer 3

Weight of the atmosphere on a surface. At sea level, the average atmospheric pressure is 1013.25 millibars (29.92 inches of mercury). Atmospheric pressure can be measured by a device called a barometer

Question 4

radiosonde

Answer 4

Is a meteorological device that is attached to a weather ballon to remotely measure weather variables with altitude. Upper air meteorological measurements are important input for numerical weather forecasting models. Variables measured by this device include altitude, geographic location, air temperature, atmospheric pressure, wind speed, wind direction, and relative humidity. Data from these measurements are transmitted to ground receivers using a radio frequency of 403 or 1680 MHz

Question 5

Ideal Gas Law

Answer 5

This law describes the physical relationships that exist between pressure, temperature, volume, and density for gases. Two mathematical equations are commonly used to describe this law: Pressure x Volume = Constant x Temperature and Pressure = Density x Constant x Temperature

Question 6

millibars

Answer 6

A unit measurements for quantifying force. Used to measure atmospheric pressure. Equivalent to 1,000 dynes per square centimeter.

Question 7

barometer

Answer 7

A scientific instrument that measures atmospheric pressure

Question 8

aneroid barometer

Answer 8

A commonly used type of barometer that measures atmospheric pressure by way of the expansion and contraction of a sealed hollow cell which is partially depleted of air

Question 9

barograph

Answer 9

The continuous record of air pressure produced by a barogram

Question 10

barogram

Answer 10

A meteorological instrument that incorporates a barometer and a data recording device to produce a continuous recording of atmospheric pressure over time

Question 11

Isobars

Answer 11

Lines on a map joining points of equal atmospheric pressure

Question 12

Rains

Answer 12

A form of precipitation. It is any liquid deposit that falls from clouds in the atmosphere to the ground surface. Rain normally has a diameter between than 0.5 and 5.0 millimeters

Question 13

Wind

Answer 13

A mass of air moving horizontally and/or vertically

Question 14

Anemometer

Answer 14

Meteorological instrument used to measure wind speed. These instruments commonly employ four methods to measure this weather phenomenon: (1) A device with three or four open cups attached to a rotating spinal. The speed of rotation is then converted into a measurement of wind speed; (2) A device that correlates propellor spin speed with wind speed; (3) A pressure plate that measures the force exerted by the moving wind at right angles

Question 15

Wind direction

Answer 15

The direction from which a wind blows. Usually measured in cardinal direction or in degrees azimuth

Question 16

Wind vane

Answer 16

A mechanical device used to measure the direction of wind flow. Usually consists of a horizontal bar with a fin at one end and a aerodynamic pointer at the other end. The center of horizontal is attached to a vertical spindle which is connected to a mechanical device that records direction

Question 17

First Law of Motion

Answer 17

An object that is motionless will continue to be motionless, while an object that is in motion will stay moving with the same velocity, in the same direction unless it is acted upon by another force. This law is sometimes called the law of inertia. First suggested by Sir Isaac Newton in 1687. See Second Law of Motion

Question 18

Second Law of Motion

Answer 18

The acceleration achieved by an object force is proportional to the net force applied to the object and inversely proportional to its mass. First suggested by Sir Isaac Newton in 1687. The following two equations describe this law: Force = Mass x Acceleration and Acceleration = Force / Mass

Question 19

Pressure gradient force

Answer 19

Force due to spatial differences in atmospheric pressure. Usually expressed in millibars or kilopascals per unit distance in meters or kilometers. This force is primarily responsible for the formation of wind

Question 20

Coriolis Effect

Answer 20

An apparent force due to the Earth rotation and the spherical shape of our planet’s surface. This apparent force causes moving objects to be deflected to the right in the Northern Hemisphere and to the left in the Southern Hemisphere. Coriolis effect does not exist on the equator. This force is responsible for the direction of flow in meteorological phenomena like mid-latitude cyclones, hurricanes, and anticyclones

Question 21

Frictional force

Answer 21

Force acting on wind near the Earth’s surface due to frictional roughness. Causes the deceleration of wind

Question 22

Eddies

Answer 22

A localized chaotic movement of gas or liquid in a generally uniform larger flow of gas or liquid

Question 23

Friction layer

Answer 23

Is the layer in the lower atmosphere where surface friction has aerodynamic effects, causing the vertical mixing of air. This layer normally extends from the Earth’s surface to about 1,000 meters (3,300 feet), however, this does vary greatly with roughness of the surface

Question 24

Cyclones

Answer 24

Area of low pressure in the atmosphere that displays circular inward movement of air. In the Northern Hemisphere circulation is counterclockwise, while Southern Hemisphere cyclones have clockwise wind patterns

Question 25

Anticyclones

Answer 25

An atmospheric pressure system consisting of an area of high pressure and outward circular surface wind flow. In the Northern Hemisphere winds from an anticyclone blow clockwise, while Southern Hemisphere systems blow counterclockwise

Question 26

Geostrophic winds

Answer 26

Horizontal wind in the upper atmosphere that moves parallel to isobars. Results from a balance between pressure gradient force and Coriolis effect

Question 27

Gradient Winds

Answer 27

Horizontal wind in the upper atmosphere that moves parallel to curved isobars. Results from a balance between pressure gradient force, Coriolis effect, and centripetal force

Question 28

Sea breeze

Answer 28

Local thermal circulation pattern found at the interface between land and water. In this circulation system, surface winds blow from water to land during the daytime. Compare with land breeze

Question 29

Land breeze

Answer 29

Local thermal circulation pattern found at the interface between land and water. In this circulation system, surface winds blow from land to water during the night. Compare with sea breeze

Question 30

Valley breeze

Answer 30

Local thermal circulation pattern found in areas of topographic relief. In this circulation system, surface winds blow from the valley bottom to areas of higher elevation during the daytime

Question 31

Mountain breeze

Answer 31

Local thermal circulation pattern found in areas of topographic relief. In this circulation system, surface winds blow from areas of higher elevation to valley bottoms during the night

Question 32

Katabatic winds

Answer 32

Any wind blowing down the slope of a mountain

Question 33

Venturi effect

Answer 33

The increase in the velocity of a fluid or gas due to the constriction of flow

Question 34

Precipitation

Answer 34

Is any aqueous deposit, in liquid or solid form, that develops in a saturated atmosphere (relative humidity equals 100%) and falls to the ground generally from clouds. Most clouds, however, do not produce precipitation. In many clouds, water droplets and ice crystals are too small to overcome natural updrafts found in the atmosphere

Question 35

Orographic uplift(Lifting)

Answer 35

The forced uplift of an air mass because of the presence of a topographic obstruction. This uplift also causes the cooling of the air mass. If enough cooling occurs condensation can occur and form into orographic precipitation.

Question 36

Hadley Cell

Answer 36

Three-dimensional atmospheric circulation cell located at roughly 0 to 30° North and South of the equator. The Hadley cell consists of rising air (Intertropical Convergence Zone) at the equator and descending air (Subtropical Highs) at 30° North and South.

Question 37

Ferrel Cell

Answer 37

Three-dimensional atmospheric circulation cell located at roughly 30 to 60° North and South of the equator

Question 38

Polar Cell

Answer 38

Three-dimensional atmospheric circulation cell located at roughly 60 to 90° North and South of the equator. Vertical air flow in the polar cell consists of rising air at the polar font and descending air at the polar vortex

Question 39

Intertropical Convergence Zone

Answer 39

Zone of low atmospheric pressure and ascending air located at or near the equator. Rising air currents are due to global wind convergence and convection from thermal heating. Location of the thermal equator

Question 40

Convergence

Answer 40

Horizontal inflow of wind into an area. Once at the area, the wind then travels vertically. Associated with cyclonic airflow

Question 41

Convection

Answer 41

Process that involves the transfer of mass and heat energy by means of vertical motions through a fluid substance like air or water

Question 42

Subtropical Jet Stream

Answer 42

Relatively fast uniform winds concentrated within the upper atmosphere in a narrow band. The subtropical jet stream exists in the subtropics at an altitude of approximately 13 kilometers (8.1 miles). This jet stream flows from west to east and has a speed that is somewhat slower that the polar jet stream

Question 43

Meridionally

Answer 43

Movement of wind or ocean waters in a direction that is roughly parallel to the lines of longitude

Question 44

Subtropical High Pressure Zone

Answer 44

Surface zone of atmospheric high pressure located at about 30° North and South latitude. These high pressure systems produced by vertically descending air currents from the Hadley Cell

Question 45

Northeast Trades

Answer 45

Northern Hemisphere surface winds found in the tropics that blow from about 30° North latitude (subtropical high pressure zone) to the equator (Intertropical Convergence Zone). These winds have a northeast to southwest direction

Question 46

Southeast Trades

Answer 46

Southern Hemisphere surface winds found in the tropics that blow from about 30° South latitude (subtropical high pressure zone) to the equator (Intertropical Convergence Zone). These winds have a southeast to northwest direction

Question 47

Westerlies

Answer 47

Dominant surface winds of the mid-latitudes. These winds move from the subtropical highs to the subpolar lows from west to east

Question 48

Polar Jet Stream

Answer 48

Relatively fast uniform winds concentrated within the upper atmosphere in a narrow band. The polar jet stream exists in the mid-latitudes at an altitude of approximately 10 kilometers (6.2 miles). This jet stream flows from west to east at speeds between 110 to 185 kilometers per hour (68 to 115 miles per hour). Also see jet stream and subtropical jet stream

Question 49

Polar Front

Answer 49

Weather front located typically in the mid-latitudes that separates arctic and polar air masses from tropical air masses. Along the polar front we get the development of the mid-latitude cyclone. Above the polar front exists the polar jet stream

Question 50

Subpolar Lows

Answer 50

Surface zone of atmospheric low pressure located at about 60° North and South latitude. These low pressure systems are produced by the frontal lifting of subtropical air masses over polar air

Question 51

Mid-latitude cyclones

Answer 51

Cyclonic storm that forms primarily in the middle latitudes. Its formation is triggered by the development of troughs in the polar jet stream. These storms also contain warm, cold and occluded fronts. Atmospheric pressure in their center can get as low as 970 millibars. Also called wave cyclones or frontal cyclones

Question 52

Polar Vortex

Answer 52

High pressure system located in the upper atmosphere at the polar regions. In this system, air in the upper troposphere moves into the vortex center and then descends to the Earth's surface to create the polar highs.

Question 53

Polar High

Answer 53

Surface area of atmospheric high pressure located at about 90° North and South latitude. These high pressure systems produced by vertically descending air currents from the polar vortex

Question 54

Polar Easterlies

Answer 54

Surface winds that originate at the polar highs and blow to the sub polar lows in an east to west direction

Question 55

Intertropical Convergence Zone

Answer 55

Zone of low atmospheric pressure and ascending air located at or near the equator. Rising air currents are due to global wind convergence and convection from thermal heating. Location of the thermal equator.

Question 56

Subtropical High Pressure Zone

Answer 56

Surface zone of atmospheric high pressure located at about 30° North and South latitude. These high pressure systems produced by vertically descending air currents from the Hadley Cell

Question 57

Subpolar Lows

Answer 57

Surface zone of atmospheric low pressure located at about 60° North and South latitude. These low pressure systems are produced by the frontal lifting of subtropical air masses over polar air

Question 58

Upper Air Westerlies

Answer 58

Consistently flowing winds that exist in the upper troposphere and have a mostly west to east direction around the planet. The upper air westerlies are normally found from about 20°N to North Pole and 20°S to South Pole. The subtropical and polar jet streams are part of this wind system.

Question 59

Jet Streams

Answer 59

Relatively fast uniform winds concentrated within the upper atmosphere in a narrow band. A number of jet streams have been identified in the atmosphere. The polar jet stream exists in the mid-latitudes at an altitude of approximately 10 kilometers (6.2 miles). This jet stream flows from west to east at average speeds, depending on the time of year, between 110 to 185 kilometers per hour (68 to 115 miles per hour)

Question 60

Polar Jet Stream

Answer 60

Relatively fast uniform winds concentrated within the upper atmosphere in a narrow band. The polar jet stream exists in the mid-latitudes at an altitude of approximately 10 kilometers (6.2 miles). This jet stream flows from west to east at speeds between 110 to 185 kilometers per hour (68 to 115 miles per hour). Also see jet stream and subtropical jet stream

Question 61

Polar Front

Answer 61

Weather front located typically in the mid-latitudes that separates arctic and polar air masses from tropical air masses. Along the polar front we get the development of the mid-latitude cyclone. Above the polar front exists the polar jet stream

Question 62

Mid-latitude cyclones

Answer 62

Cyclonic storm that forms primarily in the middle latitudes. Its formation is triggered by the development of troughs in the polar jet stream. These storms also contain warm, cold and occluded fronts. Atmospheric pressure in their center can get as low as 970 millibars. Also called wave cyclones or frontal cyclones

Question 63

Subtropical Jet Stream

Answer 63

Relatively fast uniform winds concentrated within the upper atmosphere in a narrow band. The subtropical jet stream exists in the subtropics at an altitude of approximately 13 kilometers (8.1 miles). This jet stream flows from west to east and has a speed that is somewhat slower that the polar jet stream.

Question 64

Rossby Waves

Answer 64

A large wave in the polar jet stream and the westerlies that extends from the middle to the upper troposphere. Often associated with the formation of a mid-latitude cyclone at the ground surface. Contrasts with short waves. Also called long waves.