clouds and storms 1. cloud morphology 2. types of clouds 3. the air-mass thunderstorm atoc 4720...

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Clouds and storms 1. Cloud morphology 2. Types of clouds 3. The air-mass thunderstorm ATOC 4720 class20

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Page 1: Clouds and storms 1. Cloud morphology 2. Types of clouds 3. The air-mass thunderstorm ATOC 4720 class20

• Clouds and storms

1. Cloud morphology

2. Types of clouds

3. The air-mass thunderstorm

ATOC 4720 class20

Page 2: Clouds and storms 1. Cloud morphology 2. Types of clouds 3. The air-mass thunderstorm ATOC 4720 class20

Thermoelectric effect in ice:

T- degree C; V--mV

From class-19:

[1]

[2] Supercooled water in clouds

Page 3: Clouds and storms 1. Cloud morphology 2. Types of clouds 3. The air-mass thunderstorm ATOC 4720 class20

3. Lightning and thunder

Dielectric breakdown: V>3MV/m (dry) V>1MV/m Moist with 1mm in radius;

Class-19:

Lightning: T--30,000K;Thunder: Shock waves;

Page 4: Clouds and storms 1. Cloud morphology 2. Types of clouds 3. The air-mass thunderstorm ATOC 4720 class20

1. Cloud morphology

Clouds: Mechanisms of formation [1] Convective clouds: local ascent of warm, conditionally unstable air; 0.1-10km in diameters; Vertical velocity w: a few m/s; Liquid water or ice content:

Page 5: Clouds and storms 1. Cloud morphology 2. Types of clouds 3. The air-mass thunderstorm ATOC 4720 class20
Page 6: Clouds and storms 1. Cloud morphology 2. Types of clouds 3. The air-mass thunderstorm ATOC 4720 class20

[2] Layer clouds: stratus

Forced lifting of stable air:

Examples: fog is forced lifted upwards; cold fronts lift warm air massHundres--thousands km; Lifting rates: a few cm/s;Water: a few tens

Tens of hours

Page 7: Clouds and storms 1. Cloud morphology 2. Types of clouds 3. The air-mass thunderstorm ATOC 4720 class20

stratus

Page 8: Clouds and storms 1. Cloud morphology 2. Types of clouds 3. The air-mass thunderstorm ATOC 4720 class20

[3] Orographic clouds

Forced lifting of air by hills or mountains

Uplifting velocity depends on windspeed and direction,And mountain height. Can be a few m/s;Water: a few tens

Can be transitory, or can stay for long if winds are Steady.

http://www.faa.gov/and/AC0057/AC0057.HTM

Lee waves can also produce orographic clouds;

Page 9: Clouds and storms 1. Cloud morphology 2. Types of clouds 3. The air-mass thunderstorm ATOC 4720 class20

Orographic clouds

Page 10: Clouds and storms 1. Cloud morphology 2. Types of clouds 3. The air-mass thunderstorm ATOC 4720 class20

[4] Advection fog:

Cooling of air below its dew point due to warm air is Advected to a colder surface.

Page 11: Clouds and storms 1. Cloud morphology 2. Types of clouds 3. The air-mass thunderstorm ATOC 4720 class20

Fog

Page 12: Clouds and storms 1. Cloud morphology 2. Types of clouds 3. The air-mass thunderstorm ATOC 4720 class20

[5] Arctic sea-smoke (steam fog) Meeting of two parcels of air with different temperatures; both close to be saturated.

Page 13: Clouds and storms 1. Cloud morphology 2. Types of clouds 3. The air-mass thunderstorm ATOC 4720 class20

Arctic sea-smoke

Page 14: Clouds and storms 1. Cloud morphology 2. Types of clouds 3. The air-mass thunderstorm ATOC 4720 class20

[6] Funnel clouds

Adiabatic expansion and cooling due to a rapid local Reduction in pressure.

Tornadoes or water spouts.

Page 15: Clouds and storms 1. Cloud morphology 2. Types of clouds 3. The air-mass thunderstorm ATOC 4720 class20

Funnel clouds

Page 16: Clouds and storms 1. Cloud morphology 2. Types of clouds 3. The air-mass thunderstorm ATOC 4720 class20

Funnel clouds

Page 17: Clouds and storms 1. Cloud morphology 2. Types of clouds 3. The air-mass thunderstorm ATOC 4720 class20

[7] Instabilities (Kelvin-Helmholtz instabilities)

Strong wind-shear modify cloud shape;

Page 18: Clouds and storms 1. Cloud morphology 2. Types of clouds 3. The air-mass thunderstorm ATOC 4720 class20

Billow clouds: K-H instability

Page 19: Clouds and storms 1. Cloud morphology 2. Types of clouds 3. The air-mass thunderstorm ATOC 4720 class20

Types of clouds

Many types: (International cloud Atlas)

Cumulus: StratusCirrusNimbus(combination) Cirrostratus

Page 20: Clouds and storms 1. Cloud morphology 2. Types of clouds 3. The air-mass thunderstorm ATOC 4720 class20

Cumulus

Page 21: Clouds and storms 1. Cloud morphology 2. Types of clouds 3. The air-mass thunderstorm ATOC 4720 class20

Cumulus tower

Page 22: Clouds and storms 1. Cloud morphology 2. Types of clouds 3. The air-mass thunderstorm ATOC 4720 class20

Cumulonimbus

Page 23: Clouds and storms 1. Cloud morphology 2. Types of clouds 3. The air-mass thunderstorm ATOC 4720 class20

Stratus

Page 24: Clouds and storms 1. Cloud morphology 2. Types of clouds 3. The air-mass thunderstorm ATOC 4720 class20

Cirrus clouds

Page 25: Clouds and storms 1. Cloud morphology 2. Types of clouds 3. The air-mass thunderstorm ATOC 4720 class20

Cirrostratus: halos