Lecture 5: (In)stability and local winds Flashcards
1
Q
Local wind systems- my notes
A
- Further south- more intense solar heating
- Air over the south- expands- less dense- same mass takes up more volume
- Air traveling- creates a vacuum- creating an area of low pressure at the earth’s surface- thermal rotation- air flowing to the south then to the north at altitude
- Circulation of air
2
Q
Sea and land breeze - my notes
A
- Classic example of thermal circulation
- Causes sea breeze in the day
- At night- water is warmer than the land- stores up warmth from the day
3
Q
Monsoon circulation - my notes
A
- Sun comes towards the north of the equator- over India- warming up land surface of India much quicker than the Indian ocean- storm clouds form monsoon
- Air pollution- in atmosphere- brighter the atmosphere- reflecting more sun- less surface heating- then less circulation- loss of monsoon circulation
4
Q
Impact on circulation- my notes
A
- Centre of the city= warmer than surrounding (CBD)
- Pollution dome or dust dome over the city- Los Angeles and san Francisco
- Weak prevailing winds- own winds draw pollution into the city
5
Q
The urban heat island effect - my notes
A
- City providing its own heat- tarmac- buildings- artificial heating- slow release of this during the night
- Urban areas have enhanced cloud formation- insulate urban areas- heat area
- Big tall buildings- prevent strong winds prevailing- therefore heat cannot be ‘swept’ away
6
Q
Mountain and valley breeze- my notes
A
- Air above the slope- less dense- rises in the day- hat of the cloud- Mt fuji or table top mountain
- Cool air is denser- sticks down the valley bottom- in the night
7
Q
Atmospheric (in) stability - my notes
A
- Stability governs if the air moves up or down
8
Q
Adiabatic process- ELR- my notes
A
- Air pressure and density decreases with altitude
- ELR- how fast the air is cooling- fundamental for vertical motion
- Lot or motion in altitude- big difference between temperature from surface and high altitudes- mountain windy at top
9
Q
Dry adiabatic lapse rate (DALR)- my notes
A
- Unsaturated air
- Cooling of air as it does work on its surroundings
10
Q
Moist adiabatic lapse rate- my notes
A
- Condensing- liquid water- release energy in air particle- therefore warmer the air particle alongside rises air- this off set cooling- 6 degrees/1000m- doesn’t cool just as fast- as other source of heating
11
Q
Atmospheric stability - my notes
A
- Air cannot rise stays near the surface- stable
- Unstable- air rises
12
Q
Absolutely stable atmosphere - my notes
A
- Air cooling faster than its surroundings – therefore more dense- than fall back to the surface = stable atmosphere
13
Q
Signs of stable atmosphere - my notes
A
- Fog near the surface
- Steady winds- not turbulent- concentration of pollution at surface- therefore low visibility
14
Q
Absolutely stable atmosphere- my notes
A
- Cooling slower than surrounding- therefore continue rising
15
Q
Conditional instability
A
- Surroundings lapse rate- initial cooling faster than surroundings
- But then at a point slower- therefore rises- 4000m- unstable
