Meteorology - The Atmosphere

Question 1

What are the main component gases of the atmosphere in DRY air?

Answer 1

Nitrogen 78%
Oxygen 21%
Argon 0.9%
Traces of CO2 and other gases

Question 2

What are the three gases which play the most important part in weather?

Answer 2

CO2
Ozone
Water vapour

Question 3

Describe water vapour

Answer 3

Carries large amounts of latent heat energy
A light, transparent gas
Averages less than 1%, but local concentration can vary from 0% to 4%

Question 4

Where is most of Earth’s water vapour found?

Answer 4

Low altitudes and areas of high temperature

Question 5

In what form does the Sun’s energy reach the Earth?

Answer 5

Short wave radiation

Question 6

How’s the Sun’s energy reflected back?

Answer 6

As long wave radiation

Question 7

What causes the Greenhouse effect?

Answer 7

Carbon Dioxide and water vapour absorbing some of the long wave radiation reflected back from the Sun

Question 8

Describe the general gas law as a formula. What does R stand for?

Answer 8

Pressure x Volume = R x Temperature
A gas constant for the gas or mix of gases we’re dealing with

Question 9

How is density defined?

Answer 9

The mass of a unit volume of a gas

Question 10

How does density relate to volume in a fixed mass of air?

Answer 10

Density is inversely proportional
Volume increases, density reduces

Question 11

How is pressure defined?

Answer 11

A unit of force per area

Question 12

A Hectopascal is equal to one…

Answer 12

Millibar

Question 13

What’s the average pressure of the atmosphere at sea level in hPa? And in inches of mercury?

Answer 13

1013.25 millibars
29.92

Question 14

What’s the most common type of barometer?

Answer 14

A mercury barometer

Question 15

Describe how an aneroid barometer works

Answer 15

Using a closed, evacuated capsule that expands and contracts under changing pressure

Question 16

What’s a barograph?

Answer 16

An aneroid barometer that records changing pressure in graphical form

Question 17

What are recorded on surface weather charts?

Answer 17

Barometric pressures from hundreds of observation stations

Question 18

How does one get a good overview of pressure distribution on a surface pressure chart?

Answer 18

By joining points of equal pressure

Question 19

What secondary thing do we get from surface weather charts besides seeing pressure distribution easily?

Answer 19

An estimation of the wind direction and speed at any given point

Question 20

What’s the most commonly measured weather parameter?

Answer 20

Temperature

Question 21

What does temperature describe?

Answer 21

The kinetic energy or energy of morion, of the gases that make up the air

Question 22

Name four major atmospheric phenomena which are affected by temperature

Answer 22

Rate of evaporation
Relative humidity
Wind speed and direction
Precipitation patterns and types

Question 23

For calculations in thermodynamics…must be used

Answer 23

°A( Absolute temperature) or Kelvin

Question 24

How does one convert to Kelvin from °C?

Answer 24

+273

Question 25

What are the key temperatures in Fahrenheit?

Answer 25

Freezing point of water: 32°F Boiling point of water: 212°F

Question 26

How does one convert from °C to F°?

Answer 26

T(°C) x 1.8 + 32

Question 27

How does one convert from Fahrenheit to Celcius?

Answer 27

(T(°F) -32) / 1.8

Question 28

How is density measured in meteorology?

Answer 28

Grams per cubic metre

Question 29

What's the average temperature at sea level in °C and K?

Answer 29

15°C 288K

Question 30

What's the correct gas constant for dry air at sea level?

Answer 30

1225 g/㎥

Question 31

What will happen to the msl air density constant if water vapour is present?

Answer 31

There will be a lower density for the same conditions of temperature and pressure

Question 32

What's the sea level density of water vapour?

Answer 32

About 760 g/㎥ (over half the density of the dry atmosphere)

Question 33

Air density...with altitude

Answer 33

Decreases

Question 34

At roughly what altitude is air density of that of at sea level? And quarter?

Answer 34

22,000 ft 40,000 ft

Question 35

T or F The rate of change of pressure with altitude is linear

Answer 35

F

Question 36

How is upper air data usually collected?

Answer 36

By a Radiosonde A balloon with an instrument pack that records temperature, pressure and humidity and radios it back to a ground station

Question 37

How might radar tracking be used in conjunction with a radiosonde?

Answer 37

As a means of collecting upper air data

Question 38

Which two atmospheric conditions always reduce with height?

Answer 38

Pressure and density

Question 39

How does temperature affect pressure and density?

Answer 39

Only the rate at which they fall

Question 40

Pressure and density fall...rapidly in cold air as height increases

Answer 40

More

Question 41

In warm air, the pressure aloft is always...

Answer 41

Higher

Question 42

What's the feet per mb at 10,000 ft? And the pressure at ISA?

Answer 42

36 ft 700 mb

Question 43

What's the feet per mb at 18,000 ft? And the pressure at ISA?

Answer 43

48 ft 500 mb

Question 44

What's the feet per mb at 30,000 ft? And the pressure at ISA?

Answer 44

72 ft 300 mb

Question 45

How are feet per mb calculated?

Answer 45

Feet per hPa = 96T (K) / P(hPa)

Question 46

Pressure is approximately 50% of MSL pressure at...

Answer 46

18,000 ft

Question 47

Density approximately 50% of MSL at...

Answer 47

22,000 ft

Question 48

Density is approximately 25% of MSL density at...

Answer 48

40,000 ft

Question 49

What's the lowest level of atmosphere called? What are its extremities in feet?

Answer 49

The Troposphere Approx. Ground to 8-16 km

Question 50

How's the Troposphere characterised?

Answer 50

Air cools adiabatically as it rises Temperature falls as altitude rises until the Tropopause Almost all weather occurs here

Question 51

At the poles the troposphere is...than at the equator, reaching altitudes of approximately...

Answer 51

Lower 8 km

Question 52

Why does temperature decrease with height?

Answer 52

In response to the reducing air density/thinner air

Question 53

Which layer occurs above the Tropopause?

Answer 53

The Stratosphere

Question 54

Describe the Stratosphere's composition and temperature characteristics What are its extremities?

Answer 54

The upper two thirds are ozone The temperature stays constant just above the Tropopause then steadily increases to a maximum at the Stratopause, then reducing again as the atmosphere thins further 16 - 50 km

Question 55

The stratosphere holds about...of the atmosphere's gases but very little...

Answer 55

19% Water vapour

Question 56

What is above the mesosphere? How else is it known?

Answer 56

The thermosphere The ionosphere

Question 57

What's above the stratopause?

Answer 57

The mesosphere

Question 58

What's the highest layer of Earth's atmosphere?

Answer 58

The exosphere

Question 59

...% of the mass of the atmosphere lies in the bottom...of the...

Answer 59

50% 20,000 feet Troposphere

Question 60

Why does temperature increase in the ozone layer? From what to what?

Answer 60

Heat is produced in the formation of Ozone From an ISA average of -56.5° to approximately -15°C

Question 61

Describe how ozone is formed

Answer 61

Diatomic oxygen absorbs UV radiation with wavelengths less than 240 nm and is split into two oxygen atoms This is exothermic and results in 2 ozone molecules from every three diatomic oxygen molecules and light to heat conversion

Question 62

What happens to zone when exposed to UV?

Answer 62

It absorbs UV with wavelengths up to 290 nm This UV causes it to decompose into O2 molecules and oxygen atoms This is exothermic

Question 63

What's the result of the stratosphere's temperature profile?

Answer 63

Very stable atmospheric conditions Almost completely clear of clouds/weather

Question 64

How might the stratosphere benefit long distance flight

Answer 64

It's above stormy weather It has strong steady horizontal winds

Question 65

Why does most commercial flight tend to cruise near the top of the tropopause?

Answer 65

Low temperatures and low air density, reducing parasitic drag

Question 66

How does ozone pose a threat to commercial flight? How can this be mitigated?

Answer 66

It's poisonous By fitting catalytic converters to aircraft aircon, which break the ozone down into oxygen

Question 67

What are the extremities of the mesosphere?

Answer 67

50 km to 85 km

Question 68

Why does the mesosphere switch back to cooling with altitude?

Answer 68

As air becomes progressively less dense with altitude

Question 69

Where do meteors tend to burn up? Why?

Answer 69

In the mesosphere The gases are thick enough to slow them down

Question 70

Which layers are considered to be the middle atmosphere?

Answer 70

The stratosphere and the mesosphere

Question 71

Which layer lies between 85 km and 600 km? How else is it known?

Answer 71

The thermosphere The upper atmosphere

Question 72

Why does the thermosphere increase in temperature with height?

Answer 72

UV and X-ray radiation from the sun heats the atmosphere/exosphere's molecules as they first make contact

Question 73

What can the extremities of temperature be in the thermosphere?

Answer 73

-120°C to 2000°C

Question 74

What's notable about the high temperatures in the thermosphere?

Answer 74

They would still feel cold to the skin as there are so few molecules here

Question 75

What's the outermost layer of the atmosphere? What are its extremities?

Answer 75

The exosphere 600 km to 10,000 km