Pressure systems

Question 1

Global circulation cells
Three main cells –

Answer 1

Near equator:
Hadley
Ferrel
Polar​
Near poles.

Question 2

Global circulation cells
Where on the globe are we likely to find the bands of low pressure?

Answer 2

Low pressure areas found at the Equator heat area, and in the region of 60degrees latitude

Question 3

Global circulation cells
Where on the globe are we likely to find the bands of high pressure?

Answer 3

High pressure areas found at the pole and in the region of 30degrees latitude

Question 4

Global circulation cells
When you have high level DIVERGENCE, what would pressure would you expect on the surface?

Answer 4

Low pressure found at the surface where high level divergence takes place​

Question 5

Global circulation cells
When you have high level CONVERGENCE, what would pressure would you expect on the surface?

Answer 5

High pressure found at the surface where high level convergence takes place

Question 6

Low/high pressure areas ?
fronts, secondary depression, trough, thermal low, inland water and geographic

Answer 6

Low pressure areas – fronts, secondary depression, trough, thermal low, inland water and geographic

Question 7

Low/high pressure areas ?
Ridge, cold and warm highs, blocking high, cold temporary high​

Answer 7

Anticyclone (high pressure) areas – high, ridge, cold and warm highs, blocking high, cold temporary high​

Question 8

The central issue in the formation of depressions is ____ _____ __________

Answer 8

high level divergence

Question 9

Airflow travels which direction around a low in Nth Hemisphere​

Answer 9

anti-clockwise

Clockwise in Sth Hemisphere​

Question 10

Ascending air cools leading to cloudy conditions in a high/low pressure?

Answer 10

Depression (low)

Question 11

A typical front (warm and cold front) occur when a polar depression pushes what into each other?

Answer 11

polar (cold) and tropical (warm) air into each other​

Question 12

Forms within the circulation of the main (primary) depression describes what?

Answer 12

Secondary depression

Question 13

_________ __________ rotates within the main system in a cyclonic

(clockwise for southern hemisphere, anticlockwise for north hemisphere) direction.

Answer 13

Secondary depression

Question 14

Troughs of Low Pressure
Can take on two forms (2)

Answer 14

Isobaric trough - extends into other systems

Troughs of Low Pressure

Question 15

Pressure Systems Aloft: Low
Warm or cold core, where are they likely to be found?

Answer 15

Warm core Low: more likely in tropical depressions

Cold core Low: common for a polar front depression

Question 16

Cold core will have the top pressure line bulging __
while the warm core will have the top pressure line bulging _____

Answer 16

Cold - down
Hot - up

Question 17

Thermal lows can occur over relatively warmer _____ in winter.​

Answer 17

Thermal lows can occur over relatively warmer seas or lakes in winter.​

When cold air over continents move out over a warmer sea in winter​

Question 18

Orographic Low/Depressions (Lee Low)​

Substantial wind blowing more or less ______________ to mountain. ​

Answer 18

Substantial wind blowing more or less at right angles to mountain. ​

Question 19

Orographic Low/Depressions (Lee Low)​

Windward side: air compressed = localized ____​

Answer 19

Windward side: air compressed = localized high​

Question 20

Orographic Low/Depressions (Lee Low)​

Lee side: suction effect (convergence) = low pressure​

Answer 20

Lee side: suction effect (convergence) = low pressure

Question 21

Anticyclone (High)​
What is Adiabatic warming?

Answer 21

Adiabatic warming occurs in the subsiding air, which generally results in skies becoming cloud free. ​

Question 22

Anticyclones (High)​

What is the direction of airflow around a high in the northern hemisphere?

Answer 22

Airflow is clockwise in the Northern Hemisphere​

Anti-Clockwise in Sth Hemisphere​

Question 23

Anticyclones (High)​

What winds would be associated with a high?

Which pressure would be in the centre?

Answer 23

Light winds​

Highest pressure is in the centre.​

Question 24

Anticyclones (High)​
Hazy conditions may be caused by the ___________ ________

Answer 24

The subsidence inversion may result in hazy conditions​

Question 25

Cold Anticyclones (e.g. Siberia) – Cold Core High​

Answer 25

Cold surface temperatures make the lower troposphere cold and dense​​

Classically found over Siberia in winter.​

Pressure levels bulge UP at lower level​

Bulge DOWN at high level ​

Question 26

Warm Anticyclones (e.g. Azores) – Warm Core High​

Answer 26

Excess air in the upper troposphere​

Pressure levels bulge UP at both lower and upper levels ​

Question 27

Blocking High/Anti-cyclone​

Describe: intensity, changeability, examples in summer and winter

Answer 27

The high often becomes very intense ​

​Resulting in consistent weather for a long period of time ​

Dry & warm in summer​

Overcast in winter ​