Tropical Revovling Storms

Question 1

Requirements for a TRS

Answer 1

Unstable Atmosphere
Pre existing disturbances
Deep warm ocean +26 degrees
5-25 degrees N/S for Coriolis

Question 2

Stages of development of TRS

Answer 2

Tropical Disturbance - pressure drops/trough forms
Tropical Depression - Winds 20-33kts
Tropical storm - rotating winds 34-63 knots
Tropical revolving storm - winds greater than 64kt

Question 3

Structure of a TRS

Answer 3

Eye - No cloud - Warm descending air - 20/50km
Eye wall - most severe winds and rain
Spiral rain bands - walls of cloud with clear bands of descending air

Question 4

Average diameter of TRS

Answer 4

500km

Question 5

Typhoons are located/time of year

Answer 5

South Pacific - July To October - 16 on average

Question 6

Hurricanes - Located/Time of year

Answer 6

Mid Atlantic - Less than 10 on average
June to October

Question 7

Cyclones - Location/Time of year

Answer 7

Indian Ocean - average of 7 a year
May to November

Question 8

Bay Of Bengal - Indian Ocean

Answer 8

2 cyclones

Question 9

Madagascar - cyclones

Answer 9

8 cyclones

Question 10

E. Australia - Cyclones

Answer 10

5 cyclones

Question 11

China Sea - Typhoons

Answer 11

16 on average

Question 12

SW USA - Hurricanes

Answer 12

9 on average

Question 13

SE USA

Answer 13

7 Hurricanes on average

Question 14

Where do the most TRS occur

Answer 14

South Pacific - 16 on average
July to October

Question 15

Most severe winds in TRS NH/SH hemisphere

Answer 15

NH - To the right of its track
SH - To the left of its track

Question 16

Thermal Depression

Answer 16

Surface heating causes air to rise creating low pressure at surface - localised or large scale

Question 17

Polar Low

Answer 17

Occurs in winter at high latitudes
Cold air passes over warmer water
Cold air gains energy from warmer sees triggering instability
Also lowers air density and overall pressure

100km long and usually last 48 hours

Question 18

Orographic Low

Answer 18

Low pressure develops on lee side of mountain
Calm weather conditions
Cold front can cause severe TS to develop

Question 19

What is the main energy source of a tropical revolving storm?

Answer 19

Latent heat from condensing water vapour

Question 20

SW Indian Ocean

Answer 20

5 Cyclones on average

Question 21

TRS Occur in NH between

Answer 21

June - October

Question 22

Where is Orographic depression to be anticipated

Answer 22

On the lee side of the mountain range

Question 23

Lee Low is

Answer 23

Air flow meets a mountain barrier as as it flows down the lee side warms and compresses and then produces convergence at surface forcing air to rise

Most intense if the wind flow is perpendicular to the mountain range and winds have a high velocity

Question 24

West African Tornado (WAT)

Answer 24

Example of an easterly wave - disturbances close to the ITCZ which take the form of a line of thunderstorms moving east to west

March and November

Question 25

The eye

Answer 25

Found at the centre
30-50km
Lowest surface pressure
Calmest conditions
Descending air warming at the DALR which causes eye to be warmer than the air in the eye wall

Question 26

East of Darwin average cyclones

Answer 26

9

Question 27

West of Darwin cyclones

Answer 27

5

Question 28

Number of cyclones in India a year

Answer 28

12 per year