Upper Winds

Question 1

Trade Winds are

Answer 1

Westerly winds from subtropical highs that converge at the ITCZ

Question 2

What causes clouds in the ITCZ/Type of clouds

Answer 2

Formed by convergence of NE/SE trade winds
Cu/CB/Thunderstorms - AS/NS in more stable areas

Question 3

ITCZ is referred to as

Answer 3

Doldrums
Thermal equator
Equatorial trough

Question 4

Where can icing be experienced in the ITCZ

Answer 4

16,000 ft upwards

Question 5

Thermal Winds

Answer 5

Steep pressure gradient
Air flows from warmer air mass towards cold mass

Question 6

Jet Streams Form and speed

Answer 6

Where warm and cold air masses meet
Forms in warmer air mass below tropopause
Wind speed greater than 60kt

Question 7

Upper Easterly Wind

Answer 7

NH with back to wind cooler air on your left and heat equator on your right

SH with back to wind cooler air on your right and heat equator on your left

Easterly wind not that strong due to not a strong temperature variation between heat equator and equator

SEASONAL

Question 8

Jet Stream Dimensions

Answer 8

2nm deep
200nm across
2000nm long

1:100:1000

Question 9

Sub tropical Jet stream Latitude/height/wind speeds

Answer 9

Permanent
Boundary of Hadley and ferrel cell
Move from west to east

30/40N/S
(40,000ft)
150kt in NH
80-90kt in SH

Question 10

Polar Front Jet Stream

Answer 10

Ferrel cell to polar cells
40 to 65N
50S (strongest in July)

30,000ft always below tropopause
Becomes faster in the winter
Permanent

No annual variation in latitude in south hemisphere

Question 11

ArtIc Front Jet Stream

Answer 11

60N only
20,000ft in January
Forms between artic and polar air

Question 12

Tropical Easterly Jet

Answer 12

Seasonal jet
Only in NH
Warmer continental air in north than cooler oceans in south
Found between 10/20 degrees north
45,000ft

Question 13

Where is CAT worse

Answer 13

On the cold side of the jet stream
Side of the jet adjacent to the old air and just below jets core
Never within the core

Question 14

Above the core what happens to temp

Answer 14

Subtropical air is cooler at tropopause therefore temp would increase from warm to cold

Question 15

Change Bars of Sigwx chart show

Answer 15

//

Change bars indicate change of 20kt or 3000ft

Question 16

Visible indicators associated with jet streams

Answer 16

Cirrus cloud streaks

Question 17

CAT Turbulence is

Answer 17

Clear Air Turbulence

Severe turbulence occurring in cloudless/clear skies region that can cause severe turbulence

Jet streams

Question 18

What time of year are polar front jet streams over South Pacific strongest?

Answer 18

Jet streams are typically strongest in winter.

July in SH

Question 19

Tropical Easterly Jet

Answer 19

Season easterly jet - 10/20N
Core between FL450/FL500
Flow towards the equator

Caused by summer air over equatorial ocean being cooler than land
Over South Asia/South India towards central Africa

Question 20

Jet Streams Altitudes

Answer 20

Artic Jetstream - 20,000ft
Polar Jetstream - 30,000ft
Sub tropical - 40,000ft
Equatorial - 50,000ft

Question 21

Clear Air Turbulence

Answer 21

The Erratic movement of air in the absence of any significant visual clues is caused by bodies of air moving at very different speeds

Question 22

Change bars on jet stream

Answer 22

Two thin lines on jet core line
20kt+- and change of height of 3000ft