Weather and Climate: Ch. 7 Flashcards
1
Q
Smallest scale of motion
A
Microscale Systems
2
Q
How long are microscale systems?
A
few seconds to minutes
3
Q
Examples of microscale systems
A
wind gusts, microbursts, dust devils
4
Q
Middle-sized systems less than 60 miles across, up to 600 miles wide
A
Mesoscale systems
5
Q
How long are mesoscale systems?
A
few minutes to several hours
6
Q
Examples of mesoscale systems
A
thunderstorms, tornadoes, local winds
7
Q
Largest wind patterns (Macroscale Systems)
A
- Synoptic-scale winds
- Planetary-scale winds
8
Q
Characteristics of Synoptic-scale winds
A
- smaller with diameters of 600 miles
- easily identified on weather maps
- midlatitude cyclones and anticyclones
9
Q
Characteristics of Planetary-scale winds
A
- extend around entire globe for weeks
- westerlies and trade winds
10
Q
Basic cause is unequal heating of surface
A
Global Circulation
11
Q
Where are subtropical anticyclones centered?
A
near 30° north and south
12
Q
Exentensive areas of subsiding air
A
Subtropical Anticyclones
13
Q
What do subtropical anticyclones result in?
A
low RH, fair skies, calm winds, warm temps
14
Q
World’s major deserts located in…
A
subtropical anticyclones
15
Q
Subtropical anticyclones are at …
A
Horse Latitutdes
16
Q
Results from clockwise and outward flow on north side of subtropical high
A
Midlatitude Westerlies
17
Q
How do Midlatitude Westerlies blow?
A
from west to east in midlatitudes
18
Q
Midlatitude Westerlies are highly ________
A
variable
19
Q
Midlatitude Westerlies follow a _____ path due to ______ differences
A
wavy; temp
20
Q
longest wave patterns
A
Rossby waves
21
Q
Rossby waves are a part of …
A
Midlatitude Westerlies
22
Q
Results from clockwise and outward flow on south side of Subtropical High
A
Trade Winds
23
Q
How do trade winds blow?
A
from east (NE) to west in tropical latitudes
24
Q
Doldrums are located near ________
A
equator
25
Trade winds converge (low pressure)
Intertropical Convergence Zone (ITCZ)
26
ITCZ is a part of ________
Doldrums
27
Air subsides and flows away
Polar Highs
28
Polar regions are _____
cold
29
Separates air masses of different temps
Polar Front
30
Colder air to north from warmer air to south
Polar Front
31
Area of low pressure
Subpolar Lows
32
Responsible for much of stormy weather in midlatitudes
Subpolar Lows
33
Move and vary in intensity with seasons
Semipermanent Highs and Lows
34
Pressure and wind belts follow vertical rays of sun
Seasonal Shifts
35
Seasonal Shifts shift _____ in July
north
36
Seasonal Shifts shift _____ in January
south
37
What are precipitation patterns determined by?
1. Semipermanent pressure systems
2. Distribution of land and water
3. Air temp
4. Terrain
38
High speed winds found in westerlies
Jet Streams
39
Jet Streams are _______ of miles long
thousands
40
Jet streams have a width of __-___ miles
60-300
41
Jet streams have wind speeds of ...
60-240 mph
42
Jet streams are __ to ___ miles above the surface
6 to 9
43
Jet streams form from...
horizontal differences in pressure and temp
44
Where is the Subtropical Jet Stream found
near latitude 30° above subtropical high
45
The Subtropical Jet Stream is mainly a _______ event
winter
46
How is a Polar Jet Stream front created
by large temp contrasts at surface
47
What does a Polar Jet Stream supply?
Supplies energy to drive storms
48
Directs path of storms
Polar Front Jet Stream (PFJ)
49
Polar Front Jet Stream ________ in winter when north-south air temp contrasts is _______
strengthens; greater
50
Polar Front Jet Stream ________ in summer when temp contrasts are _____
summer; less
51
How often does a Polar Front Jet Stream change?
week to week and even day to day
52
What is the general rule if PFJ stream is south of you?
weather tends to be relatively cold
53
What is the general rule if PFJ stream is north of you?
weather tends to be relatively warm
54
Jet streams play a major role in transfer of heat (meander):
- Cold air south
- Warm air north
55
How does the Zonal Flow Pattern flow?
Flow west to east, nearly parallel to latitudes
56
Air masses in Zonal Flow Pattern:
- Cold air masses stay north
- Warm air masses remain south
57
Zonal Flow Pattern tends to be a ______ weather pattern
quiet
58
Westerlies flow in a pattern of troughs (Lows) and ridges (Highs)
Meridional Flow Pattern
59
Air in Meridional Flow Pattern:
- Cold air surges south
- Warm air streams north
60
Stage set for development of storm systems
Meridional Flow Pattern
61
Arabic word for season
Monsoons
62
Wind system that changes direction seasonally
Monsoons
63
Where is the Asian Monsoon?
South and East Asia
64
What causes the Asian Monsoon?
- Difference in heating of land versus sea
- Topography
- Seasonal Shifts in ITCZ
65
Dry winds that blow off continents
Winter Monsoon
66
Warm moisture-laden air blows from sea to land
Summer monsoon
67
Summer monsoons have _______ precipitation
abundant
68
About _____ of the world's population lives in regions affected by Asian monsoons
half
69
North American Monsoon exists in...
Southwest U.S.
70
North American Monsoon brings...
rain in summer
71
What are the 5 local wind systems?
1. Sea and Land Breeze
2. Mountain and Valley Breezes
3. Katabatic (fall) Wind
4. Chinook winds
5. Santa Ana Winds
72
In a Sea Breeze, lan surfaces warm up _____ than water
more
73
When are Sea Breeze events?
- Summer event in midlatitudes
- Tropical event year round
74
Local horizontal air pressure gradient between land and water
Sea Breeze
75
How does a Sea Breeze flow?
from cool water (H) to warm land (L)
76
When does a Sea Breeze reach its maximum strength?
by mid afternoon
77
Temps can drop by ____ during the max strength of a Sea Breeze
10°
78
When does a Land Breeze occur
at night when land cools more rapidly than water
79
Cool offshore Breeze develops along with a return air flow
Land Breeze
80
Valley Breeze is best developed in ________
afternoon
81
air on mountain slopes heated more than over Valley floor
Valley Breeze (Day)
82
Valley Breeze (Day):
South Side (sun)
83
nocturnal sinking of cool air creates a mountain breeze
Mountain Breeze (night)
84
Cold, dense air over a highland area moves due to gravity
Katabatic (fall) Wind
85
Katabatic (fall) Wind is a ______ event
winter
86
Warm, dry wind that flows down leeward sides of mountains in U.S. and Canada
Chinook winds
87
Means "snow eater"
Chinook
88
Can produce rapid temp changes
Chinook winds
89
Hot, dry winds that blows from east into Southern California
Santa Ana Winds
90
Strong high pressure system centered of Great Basin
Santa Ana Winds
91
have/can produce wildfires (socal)
Santa Ana Winds
92
Gust from 80 to 90 mph
Santa Ana Winds
93
Caused by intense solar heating of ground
Desert Winds
94
whirling mass of dust laden air commonly over flat, dry terrain
Dust Devil
95
Are dust devils linked to clouds?
No
96
strong wind in combination with dust or sand storm
Haboob
97
A haboob is a ____ thunderstorms downdraft
cold
98
Irregular warm episode off west coast of South America
El Nino
99
Weather changes over a large portion of Earth (El Nino):
- Drier and mild in Midwest
- Wetter in Southern California
100
Waters off South America become unusually cool
La Nina
101
Almost opposite an El Nino event
La Nina
