ICE NUCLEATION
primary ice formation mechanism at -15 degrees C?
immersion freezing
homogenous nucleation from vapor
homogenous nucleation from liquid
immersion freezing
TRUE if air at water saturation, T=-15 deg C?
air is sub-saturated with respect to ice
air is supersaturated with respect to ice
air is at ice saturation
cannot know based on information provided
air is supersaturated with respect to ice
*HAPPENS* in our atmosphere?
Homogenous liquid drop formation from vapor
Melting of snow above 0 degrees C
Homogenous water nucleation from vapor
Freezing of water above 0 degrees C
Melting of snow above 0 degrees C
homogenous nucleation of ice in liquid drops can occur
below 0 deg C
below -15 deg C
below -20 deg C
below -35 deg C
below -35 deg C
pen and pencil theory can constrain?
immersion freezing
contact nucleation
homogenous nucleation from liquid
homogenous nucleation from liquid
TRUE if above ice saturation but below water saturation
both liquid drops and ice crystals grow
both liquid drops and ice crystals shrink
ice crystals grow at expense of liquid drops
liquid drops grow at expense of ice crystals
ice crystals grow at expense of liquid drops
TRUE for both ice and water saturation vapor pressure
increases linearly with temperature
increases exponentially with temperature
decreases linearly with temperature
decreases exponentially with temperature
increases exponentially with temperature
largest difference between saturation vapor pressures over ice and water
0 degrees C
-12 degrees C
-20 degrees C
-30 degrees C
-12 degrees C
characteristics of a good ice nuclei?
small and ice-like crystalline structure
large and ice-like crystalline structure
large and soluble
small and soluble
large and ice-like crystalline structure
Grows large by collecting supercooled liquid?
graupel
aggregate
dendrite
plate
graupel
Largest terminal velocity?
rain
graupel
dendritic snow
snow aggregate
rain
Mixed phase regime
0 to 10 degrees C
-38 to 0 degrees C
-20 to 0 degrees C
-1 to 1 degrees C
0 to 10 degrees C
ice formation without liquid?
Deposition nucleation
Immersion freezing
Contact nucleation
Homogenous freezing of aerosol
Deposition nucleation
Assuming water saturation, temperature for maximum ice depositional growth?
0 degrees C
-15 degrees C
-30 degrees C
-45 degrees C
-15 degrees C
only in cold clouds?
riming
accretion
collection
growth from vapor
riming
majority of snow melts to rain?
0 deg C
1 deg C
2 deg C
4 deg C
2 deg C
Ice nuclei active at -2 degree C?
silver iodide
volcanic ash
soot
bacteria
bacteria
assists aggregational growth of ice?
sintering
temperatures below -20 deg C
slow fall speed
supercooled liquid water
sintering
largest radar reflectivity?
melting snow crystals
rain
ice cloud particle
liquid drop
melting snow crystals
aggregation most effective due to sintering
0 degrees C
-10 degrees C
-20 degrees C
-30 degrees C
0 degrees C