precipitation

Question 1

rain

Answer 1

liquid water droplets between 0.5-0.7 mm diameter

Question 2

drizzle

Answer 2

rain subset with droplets of less than 0.5 mm

Question 3

sleet

Answer 3

freezing raindrops, combination of snow and rain

Question 4

snow

Answer 4

complex ice crystals agglomerated

Question 5

hail

Answer 5

balls of ice between 5-125mm diameter

Question 6

conditions for precipitation formation

Answer 6

for formation:
- air must cool to dew point
-condensation nuclei must be present
- droplets must grow
For sustaining:
-continuous import of water

Question 7

dew point

Answer 7

temperature at which air mass is saturated by water vapor (reach 100% relative humidity)

Question 8

airmass

Answer 8

mass of air with relative homogenous temperature and density

Question 9

convective lifting

Answer 9

air warmer than surrounding is less dense -> will rise

Question 10

frontal lifting

Answer 10

cold front meeting hot front will cause hot air to rise as fronts migrates

Question 11

orographic lifting

Answer 11

air forced to rise because of physical presence of mountains

Question 12

condensation nuclei

Answer 12

small particles/ aerosols upon which water vapor attaches to initiate condensation

Question 13

condensation

Answer 13

process driving change from water vapor to liquid water

Question 14

tipping bucket rain gauge functioning

Answer 14

count small increment of rain collected
How:
-rain falls via funnel into container divided in 2 equal part
- when specified amount of rain has drained into a part -> bucket tilt

Question 15

problem of tipping bucket gauge

Answer 15

undercatch of precipitation because:
-wind turbulence
-evaporation loss
-wetting loss
-rain splash effect

Question 16

typical climate station will record:

Answer 16

wind speed & direction
rainfall
relative humidity & temperature
radiation

Question 17

Snow variables

Answer 17

amount & distribution of snow

Question 18

liquid water content

Answer 18

unfroze water existing in snowpack

Question 19

relative density

Answer 19

ratio of snowpack to water density

Question 20

SWE

Answer 20

height of water that would be on ground if snowpack melted in place

Question 21

Snowmelt dynamic (3 phases)

Answer 21

1.Warming phase = cold snowpack require energy to rain temperature to 0 Celsius
2.Ripening = warm snowpack gains additional energy inputs and retain initial meltwater (until water holding capacity is exceeded)
3.Output = continued input of energy to melt remaining snow and ice AND water leaving by base of snowpack

Question 22

snow course

Answer 22

when multiple measurement of snow depth&SWE are made on path between 2 fixed points

Question 23

Measuring snowfall as SWE

Answer 23

weighing bucket gauge -> heated tipping bucket
snow pillow -> weight of snow forcing fluid in panel into pressure transducer

Question 24

measuring snow on the ground

Answer 24

with ruler
with snow surveys
with ultrasonic depth sensor -> continuous record of depth

Question 25

rainfall hyetograph

Answer 25

plot of rainfall depth/intensity as function of time

Question 26

cumulative rainfall hyetograph

Answer 26

plot of summation of rainfall increments as function of time

Question 27

rainfall intensity

Answer 27

plot of depth of rainfall per unit time

Question 28

how to compare rainfall event using:

Answer 28

duration
average rainfall intensity
max rainfall intensity
magnitude (total rainfall amount)

Question 29

Method for Estimating rainfall over larger area

Answer 29

Arithmetic
Thiessen polygon
Isohyetal
Inverse distance weighting

Question 30

Problems of arithmetic method

Answer 30

gages must be inside watershed
need uniformly distribution
need not too large outliers

Question 31

Problem of isohyetal method

Answer 31

value of delineation varies depend on density of gauge

Question 32

Issues converting snow into SWE

Answer 32

-time lag from precipitation to melting
-snowmelt enter watershed where it melts -> not where it falls

Question 33

Interception

Answer 33

fraction of gross precipitation that wets & adheres to above ground object, doesn’t reach the ground and returns to atmo with evaporation

Question 34

Gross precipitation

Answer 34

measured above canopy or in a clearing

Question 35

Throughfall

Answer 35

precip reaching surface directly or via canopy drip

Question 36

stemflow

Answer 36

water reaching surface by running along trunks and stems

Question 37

total interception loss

Answer 37

sum of all canopy interception and losses

Question 38

Why is interception critical

Answer 38

-significant water source for evapo
-strongly influence runoff
-canopy drips increase local erosion

Question 39

Issues measuring interception

Answer 39

Spatially variable (diff vegetation, wind, etc.)
Temporally variable (begin VS end of storm)

Question 40

Interception by vegetation hierarchy

Answer 40

conifer
broadleaves & tropical forest
Soybean, corn, wheat (grasses)

Question 41

Factors affecting interception

Answer 41

vegetation type
duration
precipitation intensity
wind
precipitation type (snow VS rain)
precipitation frequency

Question 42

depression storage

Answer 42

precip retained in ground surface depressioin

Question 43

detention storage

Answer 43

short-term storage depleted via flow away

Question 44

retention storage

Answer 44

long-term storage depleted via evaporation

Question 45

wetlands

Answer 45

transitional system between terrestrial and aquatic system where water table is at/near surface

Question 46

criteria for wetlands to meet:

Answer 46

-hydrophytic vegetation
-hydric soils
-hydrologic conditions (saturated substrate some time during growing period)