Global and synoptic scale processes - Climatology Flashcards

1
Q

Weather vs climate

A

Weather = state of atmosphere at any given time, short-term variability
Climate = long term state of the atmosphere, seasonal variability/long term trends

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2
Q

Processes responsible for vertical motion operate on:
Processes responsible for horizontal motion operate on:
Processes of similar importance operate on:

A
  • Microscale
  • Macroscale
  • Mesoscale
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3
Q

Atmosphere requires what to operate maintain the processes that operate at spatial and temporal scales

A

Energy

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4
Q

Energy cannot be

A

Created nor destroyed (first law of thermodynamics)

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5
Q

How does the Earth recieve energy from the sun (starting point)

A

By injecting radiative waves of electromagnetic energy into space and therefore into earth

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6
Q

Primary energy source from the sun

A

Radiation

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7
Q

What would result in the absense of continuous radiation from the sun

A

Atmospheric motion would cease within days due to friction

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8
Q

What carries energy between sun and earth

A

Light through a vacuum by means of electromagnetic radiation

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9
Q

How does electromagnetic radiation travel from the sun

A

In wave-like patterns/oscillations

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10
Q

Wavelengths vary and are ________ to frequency

A

Inversely proportional

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11
Q

Speed of light equation

A

Frequency x wavelength = speed of light
f x λ = c

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12
Q

Speed of light =

A

3 x 10^8 m/s

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13
Q

Absolute zero =

A

-273.15 degrees or 0 K

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14
Q

What objects emit electromagnetic radiation

A

Anything above absolute zero

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15
Q

Suns exterior temperature =

A

6000 k

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16
Q

Blackbody

A

An object that absorbs radiation that strikes from it and emits radiation at a max rate for its given temperature e.g the sun

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17
Q

The amount of energy emitted by an object is a function of its

A

Temperature

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18
Q

Equation that describes the thermal intensity of radiation from an object

A

Stefan-Boltzmann law

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19
Q

Stefan-Boltzmann law

A

Energy = emmissivity of the object x Stefan Boltzmann constant (5.67x10^-8) x temperature^4

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20
Q

Equation used to calculate maximum wavelength

A

Wiens law

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21
Q

Wiens law

A

λmax = 2897/temperature

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22
Q

Suns dominant wavelength

A

0.48 um

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23
Q

Primary constituents in the atmosphere

A

Nitrogen (78%) Oxygen (21%)

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24
Q

Which segment of the atmosphere has over 80% of the air

A

Troposphere

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25
Q

Solar constant

A

The total amount of energy of all wavelengths received at the top of the earth’s atmosphere perpendicular to the solar beam

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26
Q

Tropics recieve _____ times more

A

2.5

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27
Q

Is energy more concentrated on a perpendicular or surface at a lower angle

A

Perpendicular surface

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27
Q

Varaition in daily insolation at the top of the atmosphere is controlled by

A

Earths revolution and rotation

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28
Q

Earths speed of orbit averages

A

107,280 km hr

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29
Q

The plane in which earth moves around the sun

A

Ecliptic plane

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30
Q

The closest and furthest point of earth to the sun are the

A

Perihelion and aphelion

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31
Q

The tilt of earths axis from the plane of ecliptic

A

23.5 degrees

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32
Q

Primary reason for the seasons

A

Orientation of the polar axis in relation to its orbit around the sun

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33
Q

How does sunlight characteristics change between seasons

A

Zenith angle at noon changes between seasons, as well as the location of sunrise and sunset

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34
Q

Radiation as it passes through the atmosphere can be

A

Absorbed, reflected, transmitted

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35
Q

Absorption, reflection and transmission of radiation is dependent on

A

Wavelength

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36
Q

What happens to short wave radiation

A
  1. Reflected at the top of the atmosphere 2. Reflected or absorbed by gases in the atmosphere 3. Transmitted to the surface and then either absorbed or reflected back upward into the atmosphere (Albedo)
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37
Q

Why is the sky blue

A

Because when incoming radiation reaches earths atmosphere, some of it is scattered by atmospheric gases in all directions. Atmospheric gases scatter short waves most effectively which are blue.

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38
Q

Reflection at the earths surface is called

A

Albedo

39
Q

Albedo values:
Snow -
Light roof -
Water bodies -
Brick and stone -
Grass -
Concrete/dry -
Crops -
Forests -
Asphalt/black top -
Dark roof -
Moon -
Earths average albedo -

A

Snow - 80-95%
Light roof - 35-50%
Water bodies - 10-60%
Brick and stone - 20-40%
Grass - 25-30%
Concrete/dry - 17-27%
Crops - 10-25%
Forests - 10-20%
Asphalt/black top - 5-10%
Dark roof - 8-18%
Moon - 6-8%
Earths average Albedo - 31%

40
Q

What happens to long-wave radiation

A

The earths surface emits LW radiation at temperatures high relative to the top of the atmosphere and radiation that escapes past atmospheric gases cools the planet, Atmospheric gases emit LW radiation in all directions with the downward emissions warming the surface (greenhouse effect) and the upward emissions joining that escaped earth LW radiation.

41
Q

How does water in the atmosphere affect its buoyancy

A

More moisture equals more bouyant

42
Q

The only substance that occurs in its three states naturally on earths surface and has the highest heat capacity of all common solids and liquids (meaning it requires significant energy to change temperature)

A

Water

43
Q

Waters highest and lowest densities

A

Liquid (4 degrees) and solid

44
Q

Heat exchange associated with the change in phase of water

A

Latent heat

45
Q

Heat of vaporization

A

The amount of energy required to convert a saturated liquid into a vapour

46
Q

The motion of air is caused by

A

Energy exchanges in the atmosphere which absorbs and releases tremendous amounts of heat.

47
Q

Clasius-Clapeyron relationship

A

Saturation vapour pressure of water increases with temperature, thus warmer air can hold more water

48
Q

How does vertical motion relate to stable/unstable air

A

Vertical motion is suppressed in stable air and vertical motion is enhanced in unstable air.

49
Q

Why does air density and pressure decrease with height

A

Because the atmosphere is compressible

50
Q

How is air density calculated

A

With pressure and temperature measurements

51
Q

Parcel

A

A body of air that has specific temperature and humidity characteristics

52
Q

Ideal gas law

A

Pressure, density and temperature of a gas are dependent on each other

53
Q

Does warm air produce lower or higher density of air

A

Lower

54
Q

Rising air parcel cools by -
Falling air parcel warms by -

A
  • Expansion
  • Compression
55
Q

What are adiabatic processes

A

Describes the warming or cooling rates for a parcel of expanding or compressing air

56
Q

Adiabatic temperature change

A

Temperature change where there is no heat flow in or our of the system and is solely due to changes in pressure.

57
Q

Atmospheric temperature profiles
Warmer with height -
Cooler with height -
No change with height -

A
  • Inversion
  • Lapse
  • Isothermal
58
Q

Stability states in the atmosphere

A

Unstable,
Conditionally unstable,
Stable,
Neutral state where no vertical motion occurs,

59
Q

Three main cloud terms to describe shape and texture

A

Cumulus, stratus and cirrus

60
Q

Both oceanic and atmospheric circulations operate to do what

A

Transport thermal energy from source to sinks

61
Q

Factors controlling the motion of air

A

Pressure gradient force,
Coriolis force,
Friction

62
Q

Pressure gradient force

A

Initial stimulant for horizontal air motion

63
Q

Pressure gradient force equation

A

Pressure gradient = ∆pressure/∆change

64
Q

What does earths rotation produce

A

Coriolis force

65
Q

Coriolis force

A

An apparent force used to explain deflection created by the earths rotation, which operates to the left of motion in the southern hemisphere, and is a function of wind speed and latitude

66
Q

Coriolis force equation

A

Coriolis force = 2 x angular velocity of spin (7.29 x 10^-5) x wind speed x sin latitude

67
Q

Why is the Coriolis force called an ‘apparent’ force

A

Because it results in deflection relative only to the earth’s surface

68
Q

How does the deflection in the Coriolis effect operate

A
  1. Maximum deflection at the poles, no reflection at the equator 2. Deflection gets larger as wind speed increases
69
Q

The geostrophic wind

A

Approximates the observed wind and is a result of the balance between the pressure gradient force and the Coriolis force

70
Q

Impacts of friction on wind

A

Friction near the surface reduces wind speed and deflects it towards low pressure, and there would be no weather without friction impacting airflow.

71
Q

High pressure and low pressure systems air flow directions (southern hemisphere)

A

High pressure (anticyclone) - Anticlockwise
Low pressure (cyclone) - clockwise

72
Q

Vertical air flow in high/low pressure systems

A

High - divergence
Low - convergence

73
Q

Airmass

A

A large body of air whose physical properties (temperature, moisture content and lapse rate) are uniform horizontally for hundreds of km.

74
Q

Three factors that determine the uniformity of an airmass

A
  1. The nature of the source area where the airmass obtained its original qualities
  2. The direction of movement and changes that occur as an airmass moves over long distances
  3. The age of the airmass
75
Q

Two airmass classification factors

A
  1. Temperature (arctic, polar, tropical, equatorial)
  2. The surface type in their region of origin (maritime or continental)
76
Q

Mid-latitude synoptic weather sysytems develop in a

A

Heterogeneous atmospheric environment - large variations in airmass characteristics

77
Q

In the southern hemisphere, westerly winds lie where

A

Between the subtropical highs and southern ocean lows

78
Q

Frontogenesis

A

The origin of fronts in the mid-latitudes, caused by the the interaction of air masses of contrasting temperatures.

79
Q

Where does warm and cold air flows originate

A

Northerly and southerly flow

80
Q

Fronts are characterized by air-mass discontiniuty, with differences in

A
  1. Temperature
  2. Wind speed
  3. Pressure gradient
  4. Air density
81
Q

Vertical motion occurs along the front due to

A

Surface convergence and upper level divergence

82
Q

Cold air generally undercuts the warmer air because the warmer air

A

Is more bouyant

83
Q

Four main types of fronts

A
  1. Warm front
  2. Cold front
  3. Occluded front
  4. Stationary front
84
Q

Warm front

A

Occurs when an advancing warm air mass replaces cold air

85
Q

Cold front

A

Occurs when an advancing cold air mass approaches a warm air mass, causing the warm air to rise much more quickly forming a steep frontal boundary

86
Q

Occluded front

A

Occurs when a cold front catches up with a warm front, and the warm air mass wedged between them is lifted up (Occlusion).

87
Q

Stationary front

A

Similar to cold front in structure, but neither warm or cold air mass dominates and doesn’t move.

88
Q

Are warm or cold fronts faster and more intense

A

Cold fronts

89
Q

Three phases of the frontal wave model - Cyclogenesis

A

Phase 1: Interaction of two different air masses that leads to frontal development and instability, with vertical motion and divergence of air at upper levels
Phase 2: Low level convergence, rising motion leads to rotation and initial development of cyclonic system.
Phase 3: Cyclone matures and have warm sector that is wedged between cold and warm fronts

90
Q

The two main regions for the development of low pressure systems that affect NZ

A
  1. Southern ocean
  2. Tasman sea
91
Q

Anticylones

A

Characterized by descending air leading to stable weather conditions

92
Q

How do Anticyclones interact with depressions

A

Anticyclones tend to move slower than depressions (lows) and sometimes become stationary which can block the path of depressions

93
Q

Why is anticyclonic blocking important

A

Because High pressure systems are associated with settled weather, and can be sources of: 1. winter cold 2. enhanced atmospheric turbidity/air pollution 3. fog and low level clouds (stratocumulus) 4. belts of strong winds can occur around their peripheries

94
Q
A