Synoptic Charts/Weather

Question 1

Define isobar

Answer 1

Join places of equal atmospheric pressure

Question 2

What are isobars measured in

Answer 2

Hectopascals (hPa)- often 2hPa intervals

Question 3

What is another term for atmospheric pressure?

Answer 3

Barometric pressure

Question 4

Define atmospheric pressure

Answer 4

The weight of air pressing down on Earth’s surface.

Question 5

Anticyclones is another term for

Answer 5

High Pressure systems

Question 6

T or F- high pressure systems are cool air descending

Answer 6

true

Question 7

Characteristics of high pressure systems

Answer 7

Stable atmospheric conditions- gentle wind, clear skies, low rain.

Question 8

T or F- air pressure increases towards centre of High pressure systems

Answer 8

true

Question 9

What direction does air flow out of high pressure systems in southern hemisphere?

Answer 9

Anticlockwise outwards from centre

Question 10

What type of pressure system dominates southern Aus in summer?

Answer 10

Highs (northern by lows)

Question 11

Is a cyclone low or high pressure system?

Answer 11

low

Question 12

How do low pressure systems form?

Answer 12

When warm air rises

Question 13

Characteristics of low pressure systems?

Answer 13

Unstable atmospheric conditions- cloudy, rain, wind.

Question 14

Does air increase or decrease towards centre of low pressure systems?

Answer 14

Decreases

Question 15

Which way does air flow TOWARDS centre in low pressure systems?

Answer 15

Clockwise towards centre

Question 16

How do cold fronts form?

Answer 16

When mass of cold air overtakes slower-moving mass of warm air, forcing it to rise (clouds > rain)

Question 17

Characteristics of cold fronts?

Answer 17

As cold front passes, temps fall, rain, wind direction changes

Question 18

What direction do weather systems tend to move across southern Aus?

Answer 18

West > East

Question 19

What direction do weather systems tend to move across northern Aus?

Answer 19

East > West

Question 20

What is the biggest factor on temperature?

Answer 20

Seasonality

Question 21

What are 4 other factors that influence temperatures?

Answer 21

Extent of cloud cover; frontal activity (fall after cold fronts); wind direction (wind from south cooler, from north hotter); proximity to large water bodies (smaller diurnal range)

Question 22

T or F- high pressure systems associated with sinking air which becomes warmer and better able to retain moisture

Answer 22

t

Question 23

Wind from central Australia will likely bring

Answer 23

drier conditions

Question 24

Wind blowing onshore can often bring

Answer 24

Rain

Question 25

The closer the isobars, the stronger the...

Answer 25

Wind

Question 26

The end of a wind bar opposite the feather indicates

Answer 26

The direction the wind is coming from (draw a compass over the dot)

Question 27

Does air pressure always want to move from high to low, or low to high?

Answer 27

High to low

Question 28

How to write air pressure of a place located between isobars?

Answer 28

As a range e.g. 1012- 1016 hPa

Question 29

Are cold or warm fronts more common in Aus?

Answer 29

Cold

Question 30

Are ridges high or low pressure?

Answer 30

High

Question 31

What is a famous ridge in Australia

Answer 31

Sub-tropical ridge

Question 32

Are troughs high or low pressure?

Answer 32

Low

Question 33

What is a trough?

Answer 33

An elongated area where atmospheric pressure is low compared to surroundings. Separate 2 air masses (usually moist air one side, dry on the other)

Question 34

Famous trough in Aus?

Answer 34

Monsoon trough- moves over northern Aus annually, drawing in moist air from ocean> monsoon

Question 35

Where is the sub-tropical ridge during Nov > April?

Answer 35

South of Aus. High pressure systems move eastward along ridge, suppressing cold front activity

Question 36

What happens when the sub-tropical ridge moves north and remains over the continent from May- Oct?

Answer 36

Cold fronts associated with low pressure systems extend into Southern Aus > cold SW winds, showery.

Question 37

Do ridges generally result in drier conditions?

Answer 37

Yes

Question 38

Why are high pressure ridges sometimes associated with coastal showers?

Answer 38

When they bring onshore winds along the east coast

Question 39

What can often precede a cold front?

Answer 39

A trough (region of low air pressure)

Question 40

Are low pressure systems associated with descending or rising air?

Answer 40

Rising