lol short term memory let's go

Question 1

What is the recipe for precipitation?

Answer 1

Unsaturated air rises and cools by adiabatic expansion, reaching saturation.
Presence of cloud condensation nuclei (CCN, such as aerosol) allow for condensation, leading to formation of tiny droplets.
Droplets grow by additional condensation

Question 2

For rain to occur, what must happen

Answer 2

Velocity > water

Question 3

Warm Clouds: Collision-Coalescence

Answer 3

Growth in warm clouds (T>0°C) – mostly in the tropics and warm season in midlatitudes
• Two droplets collide and coalesce (i.e., merge)
• Promoted by large collector drops, which have high
terminal velocities
• More efficient in clouds with large distribution of droplet sizes and strong updrafts

Question 4

At top of cold/cool clouds:

Answer 4

it’s glaciated- there’s ice and vapor -> not much growth!

Question 5

What happens at T<0 Cels

Answer 5

Mixed ice and supercooled water droplets (all three phases co-exist)

1. Bergeron process
2. Riming
3. Aggregation

Question 6

What happens at T>0 Cels

Answer 6

liquid droplets and vapor (Same as warm cloud: collision-coalescence)

Question 7

What is the bergeron process?

Answer 7

• Saturation vapor pressure of ice is less than that of supercooled water
• Water vapor is satured over supercooled water, but supersatured over ice
• Ice crystals grow rapidly at the expense of supercooled droplets (via net deposition and net evaportaion)

Question 8

What is riming?

Answer 8

(liquid water freezes onto ice crystals)

Question 9

Aggregation

Answer 9

(ice crystals collide and merge via thin coating of liquid water)

Question 10

What limits the growth of ice particles by the Bergeron process?

Answer 10

The amount of supercooled water in the cloud & The time an ice particle remains in the cloud

Question 11

Describe snow crystals

Answer 11

Snow crystals: single crystals

• Shapes of ice crystals (crystal habits) depend on temperature and degree of supersaturation (for ice)

Question 12

Snowflakes

Answer 12

Snowflakes: aggregates of snow crystals
Warmer clouds: snowflakes formed by riming which forms dense “wet” snowpack (snowball fights)
Colder clouds: snowflakes formed by aggregation which forms less dense powdery snowpack (skiing)

Question 13

Lake Effect Snow:

Answer 13

develops as the warm lake waters evaporate into cold air

Question 14

Warm clouds:

Answer 14

predominant in tropics

Question 15

Cold Clouds:

Answer 15

Most middle-latitude precipitin starts out as snow, then melts to rain.

Question 16

Graupel

Answer 16

Rimed ice crystal

Question 17

Hail

Answer 17

concentric layers of ice built around graupel- wet growth results in solid ice

Question 18

possible types of precipitation originating from a cold cloud:

Answer 18

Rain, Snow, Hail, Graupel, Freezing rain, Sleet