Weather and Climate: Ch. 4 Flashcards
1
Q
Moving water molecules from a liquid to vapor and back to liquid
A
Hydrologic Cycle
2
Q
Solid directly to gas (without passing through liquid state)
A
Sublimation
3
Q
What is an example of sublimation?
A
shrinking of ice or snow
4
Q
Water vapor directly to a solid
A
Deposition
5
Q
What is an example of deposition?
A
frost
6
Q
Amount of water vapor in air
A
Humidity
7
Q
Measures how near the air is to saturation
A
Relative Humidity (RH)
8
Q
Air at 100% relative humidity = …
A
air is completely saturated
9
Q
Relative humidity _______
A
changes
10
Q
RH varies _____ with temp
A
inversely
11
Q
RH ________ as temp drops and __________ as temp rises
A
increases; decreases
12
Q
Temp at which water vapor begins to condense
A
Dew Point Temp
13
Q
Air reaches saturation at the …
A
dew point temp
14
Q
What is a good measure of amount of water vapor in air
A
Dew Point Temp
15
Q
High dew points = …
A
high water vapor content
16
Q
low dew points = …
A
low water vapor content
17
Q
When air temp and dew point are far apart, RH is _____
A
low
18
Q
When air temp and dew point are close, RH is ____
A
high
19
Q
When air temp and dew point are equal, RH is ________
A
100% (saturated)
20
Q
Where are dew points highest?
A
over Gulf Coast states
21
Q
Dew points are lowest over _______
A
interior
22
Q
Dew point <55:
A
pleasant
23
Q
Dew point 56-60:
A
comfortable
24
Q
Dew point 61-65:
A
getting sticky
25
Dew point 66-70:
uncomfortable
26
Dew point 71-75:
opppressive
27
Dew point 76+:
miserable
28
In cold, polar air, low dew points = ____ air
dry
29
In cold, polar air, low dew points = _____ RH
high
30
During winter, RH inside a home can drop to extremely ___ values
low
31
Low RH inside a home can cause:
dry skin and chapped lips
32
Temp changes that result from changes in pressure
Adiabatic Temperature Changes
33
Imaginary volume of air
Parcel
34
Has no interchange of heat with its surroundings
Parcel
35
Characteristics of Adiabatic cooling:
- Rising parcel of air expands and cools
- Sinking parcel is compressed and warms
- Clouds form as air rises and cools
36
Unsaturated parcel of air (RH < 100%)
Dry Adiabatic Rate (DAR)
37
What is the DAR rate of heating or cooling?
10℃ for every 1000 meters (5.5℉ every 1000’)
38
DAR is ______
constant
39
Altitude at which parcel reaches saturation and clouds form
Lifting Condensation Level (LCL)
40
Rate of temp decrease for a saturated (RH = 100%) parcel of air
Wet Adiabatic Rate (WAR)
41
What does lifting result in?
cooling, condensation, cloud formation, and release of latent heat
42
WAR is less than ___ and not _____
DAR; constant
43
Why is WAR not constant?
due to release of latent heat
44
WAR average at:
6℃/1000m or 3.3℉/1000’
45
How do clouds develop?
As an air parcel rises and cools below dew point
46
What are the 4 triggers for cloud development?
1. Orographic Lifting
2. Frontal Lifting
3. Convergence
4. Convection and Clouds
47
Characteristics of Orographic Lifting
- Air is forced upward by elevated terrain (mountains)
- Air descends leeward slopes (downwind side)
- Mountain ranges create different climates
- Rain Shadow Desert
48
Air is forced upward by elevated terrain (mountains):
- Ascends windward slopes
- Expands and cools, increasing RH
- Clouds and precipitation can develop (LCL)
49
Air descends leeward slopes (downwind side):
- Compressed and warms
- Existing clouds vaporize and RH decreases
50
In orographic lifting, moist climates on ___________ slopes
windward
51
In orographic lifting, dry climates on ___________ slopes
leeward
52
Dry conditions that extend many miles downwind of a mountain range
Rain Shadow Desert
53
Characteristics of Frontal Lifting
- Warmer, less dense air is forced over cooler, denser air
- Cloud development and possible precipitation
- Responsible for most precipitation in mid-latitudes
54
Characteristics of Convergence
- Horizontal inflow of air that results in vertical lifting of air
- Responsible for clouds and precipitation in a low pressure system
55
Sea breeze convergence produces thunderstorms in ________ _________
central Florida
56
In the convection and clouds trigger, unequal surface heating causes pockets of air (thermals) to ____
rise
57
In the convection and clouds trigger, when warm parcels of air rise above LCL, ...
clouds and afternoon showers may form
58
Stable air = ...
parcel resists vertical motion
59
In stable air, parcel is ______ than surrounding air
cooler
60
In stable air, parcel more ______ and sinks to its original position
dense
61
Unstable air = ...
parcel rises to an altitude where temp equals its surroundings
62
In unstable air, parcel is ________ than surrounding air
warmer
63
Rate of temp change in atmosphere with height
Environment Lapse Rate (ELR)
64
Characteristics of Environmental Lapse Rate (ELR)
- Air surrounding parcel
- Has to be given to you
65
What are the 3 types of stability?
- Absolute Stability
- Absolute Instability
- Conditional Instability
66
Lifting parcel of air is colder and heavier than surrounding air
Absolute Stability
67
Absolute stability resists _______ motion
vertical
68
In absolute stability, ELR _____ than WAR or DAR
less
69
In absolute stability, if parcel is forced to rise, clouds will be...
thin and widespread
70
There are _____ skies in absolute stability
clear
71
Stability enhanced by...
- Radiational cooling at night
- Cooling of air mass traveling over a cold surface
- Sinking of air
72
Rising air parcels are warmer and less dense than surrounding air
Absolute Instability
73
In absolute instability, ELR _______ than DAR or WAR
greater
74
When does absolute instability occur?
on warm, humid summer days when solar heating is intense
75
Absolute instability brings...
pop-up thunderstorms
76
Instability enhanced by...
- Warming lower atmosphere during day
- Heating cold air mass as it passes over a warm surface
- Upward movement of air
77
In conditional instability, ELR is ______ WAR and DAR
between
78
Altitude at which air rises because of its own buoyancy
Level of free convection (LFC)
79
LFC is a part of...
conditional instability
80
In conditional instability, stability (unsaturated) occurs _____ cloud
below
81
In conditional instability, unstable (saturated) occurs _____ cloud base
above
82
Conditional instability brings ________
thunderstorms
83
In conditional instability, thunderstorms seldom extend into stratosphere = _______
stable
84
In conditional instability thunderstorms spread ________ forming an _____ top
horizontally; anvil
