Gravity

Air resistance

Curvature Effect

Solute EffectPure Water:High Vapor pressureSmall rain drop

Salty Water:Low Vapor pressureLarge rain drop

Terminal velocity

0.0001

0.001

0.01

0.1

1

10

100

1000

10000

0.0001 0.001 0.01 0.1 1 10

Drop radius (mm)

Rain

Drizzle

0.5 mm 5 mm

Cloud

Table 7-1, p. 166

Bergeron Process(ice-crystal process)

Ice grows at the expense of water drops.

Accretion(riming)

Ice collecting suppercooled water drops

Results in icy snow pellets called graupel

Aggregation

Ice collecting small ice particles to make a snow flake

Virga

Fall Streaks -- icy crystals or snow falling

Dendrite snow crystal

Fig. 7-11, p. 172

Fig. 7-12, p. 173

Rime: super cooled drop freezing on contact

Freezing Rain: rain freezes on contact.

Fig. 7-21, p. 180

Fig. 7-23, p. 182

Days with Freezing rain

Fig. 5, p. 183

Fig. 7-18, p. 179

5.5 inches

Polarized light