Atmospheric water and weather Flashcards
water is in _____ forms
visible and microscopic forms
only common substance to occur in all three states naturally
water
hydrologic/water cycle is the
movement of water throughout the atmosphere, hydrosphere/cryosphere, lithosphere and biosphere
what drives the water cycle
energy exchange (sun) and gravity
weather
short-term day to day conditions of the atmosphere
climate
long term average (30 years) of weather conditions and extremes in a region
meteorology
study of atmosphere (short term weather)
nature of the hydrogen-oxygen bond
oxygen bond gives hydrogen a slight positive charge and oxygen side a slight negative charge
water molecules are ____ to each other
attracted
what is the result of the slight charges in the hydrogen-oxygen bond
polarity
hydrogen bond
positive hydrogen side attracts the negative oxygen side
unique properties water has BECAUSE OF the hydrogen bonds
- surface tension
- capillarity
surface tension
allows objects with a higher density than water such as razor blades and insects to float on a water surface
capillarity
tendency because of the hydrogen bonding for water to “climb” the edges of glasses, and test tubes… or to move between soil particles
what must happen for water to change from one state to another
heat must be added or released from it
the amount of heat absorbed or released must be sufficient to
affect the hydrogen bond between molecules
what is important to atmospheric processes
the relation between water and heat energy
heat exchanged between physical states of water provides more than ____ of the energy that powers the general circulation of the atmosphere
30$%
phase change
each change between states of water
examples of phase changes between solid and lique
- melting
- freezing
what happens as water cools from room temp
it contracts in volume
it increases in density
why does cooling water increase in density
because the same number of molecules now occupy a smaller space
what state is water when its cooled to the point of greatest density (4 degrees celsius)
liquid state
what happens if cooling continues past 4 degrees celsius
it expands as more hydrogen bonds form among the slowing molecules
pure ice has _____ times the density of water
0.91
why does pure ice float
because it has 0.91 density of liquid water
characteristics of water in a liquid state
- non-compressible fluid
- assumes shape of the container
how can ice change to water
heat must increase the motion of water molecules enough to BREAK some hydrogen bonds
1 gram of ice needs _____ heat to become 1 gram of water (0 degrees Celsius)
80 calories of heat absorbed
1 gram of liquid water at 0 degrees Celsius has to absorb ____ heat to become 1 gram of liquid water at 100 degrees Celsius
100 calories absorbed
1 gram of water at 100 degrees celsius must absorb ____ heat to become 1 gram of water vapour at 100 degrees celsius
540 calories
1 gram of water vapour at 100 degrees celsius must ____ heat to become 1 gram of liquid water at 100 degrees Celsius
release 540 calories (-540 calories
1 gram of liquid water at 100 degrees Celsius has to ____ heat to become 1 gram of liquid water at 0 degrees Celsius
release 100 calories (-100)
1 gram of solid water at 0 degrees celsius needs _____ to become 1 gram of liquid water (0 degrees Celsius)
release 80 calories (-80)
latent heat
heat energy of a phase change
will temp increase while latent heat in changing state
NO
water vapour characteristics
- invisible
- compressible gas
- molecules are independent of each other
is water boiling point affected by air pressure differences
yes
latent heat of vaporization
amount of heat energy needed to change liquid to gas
latent heat of condensation
water vapour condenses to a liquid (540 calories
latent heat of sublimation
gram of ice transforms into vapour (680 cal)
what is the dominant cooling process in Earth’s energy budget
the latent heat exchange
where is there a surplus of radiation energy
at the surface of the atmosphere
opposite of latent heat of evaporation
latent heat of condensation (release 586 cal for every gram of water)
when do small, puffy fair-weather clouds release water vapour
when it condenses into droplets
____ use infrared sensors to monitor water vapour in the lower atmosphere
satellites
how is water vapour monitored in the lower atmosphere
satellites using infrared sensors
water vapour absorbs _____ wavelengths
long (infrared)
why is it possible to distinguish areas of relatively high and relatively low water vapour
based on water vapour absorbing long wavelengths (Infrared)
_____ percent of water is fresh water
2.78
water runs (up or downhill) to _____
downhill to sea level
is water in oceans freshwater
NO
most water comes from the ____
oceans (97%)
breakdown of freshwater
- 78% = surface
- 11% = deep ground water
- 11% = ground water
- 0.18% = soil moisture
is the water cycle in continuous motion
yes
what fuels the hydrological cycle
latent heat change
what drives the hydrological cycle
sun and gravity
is the speed of the reservoir in the hydrological cycle important
yes - melting ancient ice can be dangerous
what fuels the formation of clouds
evaporation
transpiration
humidity
amount of water vapour in the air
what determines are sense of comfort
humidity and air temp
absolute humidity
measure of the actual number of water molecules present as vapor in the air
max absolute humidity varies with ____
temperature
absolute humidity AKA
vapor pressure
warmer air can hold ____ water vapour
more
colder air can hold _____ water vapour
less
relative humidity
absolute humidity / max humidity possible AT THE SAME TEMP
problem with relative humidity
don’t know the size of the air parcel
(warmer = bigger parcel = less RH)
saturated air is ___ relative humidity
100%
desert air is ____ relative humidity
10 to 30 precent
when is relative humidity 100%
when the air is saturated with max water vapour FOR ITS TEMP
what happens at mid-day to relative humidity and parcel of air
air temp is rising = evaporation rate exceeds the condensation rate = same volume of water vapor is now 50% max possible capacity
air parcel and humidity in the evening
air temp just past peak =evaporation rate exceeds condensation = relative humidity is low
does absolute humidity change as the air parcel changes
NO
warmer air
greater max water vapour possible
colder air
lesser maximum water vapour possible
what does relative humidity tell us
how near the air is to saturation
what happens when more water is added or temp is decreased to something at saturation
active condensation (clouds, fog or precipitation )
dew-point temperature
temp where something containing air becomes saturated and the net condensation begins forming water droplets
does absolute saturation show if the saturation point is close
- NO
what happens to an air parcel as it increases in the sky
it compresses
_____ is the temp when we have REACHED saturation
dew-point temp
when is the air saturated (in terms of dew-point)
when dew-point temps and air temp is the SAME
frost point
temp of the air becoming saturated leads to the formation of ice (temps below freezing)
what kind of relationship exists between air temp and relative humidity
inverse (as temp rises, relative humidity falls)
when is relative humidity highest
at dawn = air temp is lowest
when is relative humidity lowest
late afternoon - when higher temps increase the rate of evaporation
why does relative humidity change throughout the day
because the temp,rate of evaporation, varies from morning to aftenoon
humidex
relates sensed heat to temp and relative humidity
with the humidex, when is it there the MOST discomfort
with high humidity and low wind
why does it feel hotter than it actually is
body cannot evaporate sweat
what state is less dense
solids or liquids
solid state of water
what happens to water as it freezes
exapands
cohesion
stick to itself (drops)
adhesion
stick to other things (dew)
water has high ____ -and _____ rates
cohesion and adhesion
when heat is released water moves to _____ energy phases
lower
when heat is added water moves to ____ energy phases
higher
when are storms more intense
over high temps = there is more evaporation
how do storms (hurricanes) get energy
from phase changes
___ of water is in glacials
99.4%
____ of water is surface water
77.78%
