C:Atmospheric Environments Flashcards
(22 cards)
What are the climate controlling factors of CTWM
-Latitude
-Ocean Proximity
-West Side of Continent
-Polar Front
Precipitation
How does the Polar front affect the CTWM climate
Subtropical and Subpolar air meet in these latitude giving rise to rise pressure producing unsettled stormy conditions
How does Precipitation affect the CTWM climate
The prevailing wind is generally onshore, and most of the rainfall is either orographic or cyclonic rainfall
Characteristics of CTWM climate
- Mild Summers and Mild Winters=small annual temperature range
- In the summer the mean temperature is lower than average for that latitude, but in the winter it is higher
- Temperatures increase as you move away from the coast
- High humidity
- rainfall throughout the year, 2500mm a year
What/Where is the polar front, and how does it effect the movement of the air.
It is the boundary between the Polar and Ferell cells, it is the meeting point for cooler air from the poles and warmer air from the tropics. It cause the convergence and uplift of the air, where low pressure depressions are created
What is a Rossby Wave
They are giant meanders in high altitude winds that have a major influence on weather. They help transfer heat in an attempt to return atmosphere to balance. They are observed as large-scale meanders of the jet stream
What is a Jet Stream
Bands of strong wind in the upper levels of the atmosphere in the tropopause, they exist within Rossby waves. They blow from West to East and follow the boundaries between warm and cool air
How does the movement of the Polar Jet stream affect the weather in the UK.
- When it moves North of the UK, we get warmer and wetter condition due to low pressure
- When it is South of the UK we get cooler drier conditions as there is high pressure
- When it is directly above we get unsettled conditions
When is the PFJS strongest
During the winter as there is a greater temperature contrast between the warm and cool air
What is an air mass
Parcels of air of the same temperature and humidity that bring distinct weather features to a region
What does the temperature and humidity of an air mass depend on
Its origin and its fetch (journey over land and sea)
Where do air masses form and why. Give examples of source regions
High pressure regions, as air spends a lot of time stagnant and where conditions are calm. Source regions include the Azores and Northern Canada
What is an occluded front
When a cold front catches up with a warm front, as a warm front moves slower than a cold front due to friction
Describe a warm front
Warm air is advancing and is being forced to override cool air
Describe a cold front
Advancing cold air undercuts a body of warm air
What is a depression
An area of low pressure- unstable rising air
Describe the characteristics of a depression in CTWM climates
- Air moves from sub-tropical and polar regions, meets and ascends forming low pressure
- Lowest pressure in the centre
- Winds blow inwards towards the centre-Anticlockwise
- Steep pressure gradient so winds are strong
What are the 3 stages in a depression lifecycle
- Embryo Depression
- Mature Depression
- Decaying depression
What conditions do depressions bring to the UK in winter and Summer?
Winter: Stormy and Wintery Conditions
Summer: Periods of prolonged rainfall
What are anticyclones
High pressure systems, a zone of stable sinking air
Characteristics of Anticyclones
- Air moves from subtropical and polar regions meets and descends forming high pressure
- Highest pressure is in the centre
- Subsiding air, few clouds, little rain
What conditions do anticyclones bring in summer and winter
Summer: Fine, warm weather with little rain
Winter: Cold, dry days with little winds. Severe night time frosts can develop due to clear skies
