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
Thermoelectric effect in ice:
T- degree C; V--mV
From class-19:
[1]
[2] Supercooled water in clouds
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;
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:
[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
stratus
[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;
Orographic clouds
[4] Advection fog:
Cooling of air below its dew point due to warm air is Advected to a colder surface.
Fog
[5] Arctic sea-smoke (steam fog) Meeting of two parcels of air with different temperatures; both close to be saturated.
Arctic sea-smoke
[6] Funnel clouds
Adiabatic expansion and cooling due to a rapid local Reduction in pressure.
Tornadoes or water spouts.
Funnel clouds
Funnel clouds
[7] Instabilities (Kelvin-Helmholtz instabilities)
Strong wind-shear modify cloud shape;
Billow clouds: K-H instability
Types of clouds
Many types: (International cloud Atlas)
Cumulus: StratusCirrusNimbus(combination) Cirrostratus
Cumulus
Cumulus tower
Cumulonimbus
Stratus
Cirrus clouds
Cirrostratus: halos