Meteorology

Question 1

Lowest level of the atmosphere (where weather occurs)?

Answer 1

Troposphere

Question 2

Affects of variations in air density on aircraft performance

Answer 2

• Alter maximum take off weight
• Alter lifting force of aircrafts wing
• Alter the trust of the propellor or jet

Question 3

Flying at constant QNH, how does height change when encountering change in surface pressure?

Answer 3

High to low

• approaching low less air above you
• to maintain same pressure aircraft must decrease height
• height will be lower than indicated

Low to high

• approaching high more air above you
• to maintain same pressure aircraft must increase height
• height will be greater than altimeter

Question 4

ISA

Answer 4

MSLP: 1013.25 @ 15•C

Lapse Rate 2•C/1000ft

Question 5

Stable environment

Answer 5

Environment will return to original state if disturbed.

Question 6

Unstable environment

Answer 6

Environment will rapidly change if disturbed.

Question 7

DALR

Answer 7

Dry atiabatic lapse rate

3•C/1000ft

Question 8

SALR

Answer 8

Saturated Adiabatic Lapse Rate

1.5•C/1000ft

Question 9

Temperature inversion

Answer 9

Stable layer where temperature remains the same or increases with height

Question 10

Parcel of air if warmer than surrounding environment

Answer 10

Will continue to rise due to positive buoyancy.

Unstable

Question 11

What is RH

Answer 11

Ratio of vapour pressure in air/saturation vapour pressure.

When RH = 100% then air is saturated

Question 12

What is Dewpoint?

Answer 12

Temperature that air would become saturated if cooled down.

When T=Td air is saturated

Question 13

Relationship between dewpoint and RH

Answer 13

Closer T and Td are together the higher the RH.

If T = Td, RH = 100%

RH - 100 - 5(T-Td)

Question 14

Four main mechanisms responsible for cloud formation

Answer 14

• Convection (heating and instability)
• Orographic
• Turbulence
• Widespread/Synoptic ascent (frontal and iseotropic)
• Also convergence…

Question 15

Conventions for measuring and reporting wind

Answer 15

• measured at 10m AGL
• prevailing wind is a 10m mean
• strongest wind in last 10min is the gust
• direction is where the wind has come from

Question 16

Types of locally driven wind are experienced at Nowra? When are they most likely to occur?

Answer 16

• sea breeze - hot days, between midday and 6pm
• land breeze - cool nights, midnight and 9am
• katabatic - cool nights, midnight and 9am
• downslope winds - in between successive cold fronts, strongest overnight and in early morning

Question 17

What way does wind circulate around synoptic features?

Answer 17

• clock wise around a low/cyclone (SH)

- anti-clockwise around a high/anticyclone (SH)

Question 18

Inter Tropical Convergence Zone (ITCZ)

Answer 18

Area near the equator (normally represented by a region of convective activity and instability) where the trade wind regimes meet