weather systems

Question 1

air mass

Answer 1

n air massis a large body of air where fairly uniform temperature and moisture characteristics is observed. It can stretch several thousand kilometres across and extend to the top of the troposphere. Each air mass shows a distinctive combination of conditions at the surface, particularly temperature, environmental temperature lapse rate, and humidity. These properties are acquired in source regions over which the air moves slowly or stagnates

Question 2

2/8/18 2 Five types of air masses are distinguished with respect to latitude

Answer 2

arctic (A), antarctic (AA), polar (P), tropical (T), and equatorial (E)

Question 3

For the type of underlying surface, two subdivisions are use

Answer 3

: maritime (m) and continental (c

Question 4

Six important air mass types can be identified from these descriptive labels

Answer 4

s: cA, cP, cT, mP, mE, mT.

Question 5

north american air masses

Answer 5

mainly cP and cA

Question 6

Air masses are usually separated by a well-defined boundary between them; these transitional zones are termed

Answer 6

fronts

Question 7

In North America, the boundary between polar and tropical air masses produces the well-defined _________ that is located below the axis of the polar front jet stream

Answer 7

polar front

Question 8

2/8/18 4 North American Air MassesAir masses are usually separated by a well-defined boundary between them; these transitional zones are termed fronts. In North America, the boundary between polar and tropical air masses produces the well-defined polar front that is located below the axis of the polar front jet stream. Source: Strahler, Alan and Archibold, O. 2011 Because unequal heating of the Earth’s surface, the atmosphere and oceans exhibit a complex circulation pattern of air and water flows, which in turns, redistribute absorbed solar radiation more evenly by way of various convection loops (poleward heat transport)

Answer 8

ower Latitudes: through thermally direct Hadley Cells. Mid, High Latitudes: through Rossby Wave mechanis

Question 9

Due to pressure gradients air masses are set in motion between region ______________

Answer 9

f high and low pressure

Then driven along by the general global wind system and by regional pressure gradients associated with centres of high and low pressure

Question 10

2/8/18 5 Due to pressure gradients air masses are set in motion between regions of high and low pressure. Then driven along by the general global wind system and by regional pressure gradients associated with centres of high and low pressure. Air masses can move far from their source regions since pressure varies regionally over great distances. This type of movement is observed in the midlatitudeatmosphere, where

Answer 10

travelling cyclones and travelling anticyclones contribute to changing weather conditions as they pass across a region

Question 11

2/8/18 5 Due to pressure gradients air masses are set in motion between regions of high and low pressure. Then driven along by the general global wind system and by regional pressure gradients associated with centres of high and low pressure. Air masses can move far from their source regions since pressure varies regionally over great distances. This type of movement is observed in the midlatitudeatmosphere, where travelling cyclones and travelling anticyclones contribute to changing weather conditions as they pass across a region.Because of convergence and upward motion, in a travelling cyclonic system air will rise and be cooled adiabatically. When the air is moist, condensation or sublimation may lead to

Answer 11

cyclonic precepitation

Question 12

hen pressure gradients are steep and the air is laden with water vapour, strong winds and heavy rain or snow can accompany them (producing a _______

Answer 12

cyclonic storm

Question 13

2/8/18 6 Travelling cyclones fall into three types distinguished primarily by their intensity and geographic location:

Answer 13

Midlatitudes, arctic and Antarctic - wave cyclones or depressions 2)Tropical and subtropical – tropical cyclones (which can intensify to hurricanes and typhoons) 3)tornado

Question 14

a large mass of inward-spiralling air that repeatedly forms, intensifies, and dissolves along the polar front

Answer 14

wave cyclone

Question 15

wave cyclone usually occurs when

Answer 15

n two large anticyclones lie on either side of the polar front

Question 16

The boundary between the two high-pressure cells is necessarily a region of lower pressure and so forms a

Answer 16

low pressure trough

Question 17

swhere warm air is moving over a region of colder air.

Answer 17

warm front

Question 18

hen a cold air mass advances into the zone occupied by the warm air mass

Answer 18

a cold front is developed

Question 19

The colder air of the faster-moving cold front remains next to the ground, forcing the warm air ahead of it to rise along the

Answer 19

occluded front

Question 20

the simplest form of tropical weather system, which is a slowly moving, convectively active trough of low pressure that is driven westward by the trade winds.

Answer 20

easterly wave

Question 21

, a disturbance that forms near the centre of the equatorial trough.

Answer 21

weak equatorial low

Question 22

Polar OutbreaksOccasionally, the penetration of powerful tongues of cold polar air from the midlatitudes into very low latitudes cause another distinctive feature of low-latitude weather. The leading edge of these polar outbreaks is marked b

Answer 22

squalls along the cold front, and is followed by unusually cool, clear weather with strong, steady Winds (best developed in the Americas).

Question 23

Tropical weather disturbances range from weak tropical lows to powerful and destructive

Answer 23

tropical cyclones(“a storm of tropical origin of small diameter with a minimum surface pressure below 95 kPa, with violent winds greater than 125 kph, and accompanied by torrential rain.”)

Question 24

tropical cyclone is known variously as a

Answer 24

as a hurricane in the western hemisphere, a typhoon in the western Pacific, and a cyclone in the Indian Ocean

Question 25

Revolving around a central “eye,” these storms can be

Answer 25

e 30 to 50 km in diameter and characterized by light winds and clear skies

Question 26

The Saffir-Simpson scale rate

Answer 26

s the intensity of tropical cyclones. The rating is based on the central pressure of the storm, mean wind speed, and height of accompanying storm surge, which can raise sea level several metres above normal. Category 1 storms are weak, while Category 5 storms are devastating.

Question 27

s a small with an intense cyclonic vortex in which air spirals at tremendous speed

Answer 27

tornado

Question 28

assesses the intensity of North American tornadoes on the basis of the damage they caused (F1 to F5

Answer 28

fujita scale

Question 29

The Fujita scale has been criticized since it is biased toward the worst damage, even though no consideration is given for building type or method of construction (resulting in overestimated wind speeds in some cases). As result, in Canada and the United States, the F-scale was replaced in 2007 by th

Answer 29

Enhanced Fujita (EF) scale. (incorporates 28 damage indicators, including different types of buildings and trees for which varying degrees of damage are assessed)