Download Unit 2 Section 5 Vertical Motion in the Atm

Photo: Pamela R. Cox 2013 Elizabethtown, Kentucky
Learning Targets:
I can discuss key functions that the atmosphere
serves that enables life to exist on Earth.
I can explain factors that cause the dynamic
balance in the atmosphere to change.
I can model and explain the relationships and
energy flow existing in various Earth systems
(atmosphere).
Photo: Pamela R. Cox 2013 Elizabethtown, Kentucky
46.What is an air parcel?
An air parcel is a block of air with uniform
temperature and pressure throughout
47.In what 4 ways can the air parcel change
over time?
The air parcel can change over time by rising,
falling, or emitting or absorbing heat.
Photo: Pamela R. Cox 2013 Along Bluegrass Parkway, Kentucky
48. If the pressure of the surrounding
environment changes, the pressure of the
parcel changes, but it does not exchange
heat or chemicals with the surroundings and
therefore may behave differently from its
surroundings.
Photo: Pamela R. Cox 2013 Elizabethtown, Kentucky
49.Many weather patterns start with rising air.
50.Air does not rise simply because it is warm.
Rather, air that becomes warmer than its
surroundings becomes buoyant and floats on
top of cooler, denser air in the same way
that oil floats on top of water. This buoyant
motion is called convection.
Photo: Pamela R. Cox 2013 Along Bluegrass Parkway, Kentucky
51.This is also a key factor in weather and
climate. water
52. What percent of the atmosphere typically
consists of water vapor? two to three percent
Photo: Pamela R. Cox 2013 Elizabethtown, Kentucky
53.What does relative humidity compare?
the amount of water vapor in the air to the
maximum amount that air can hold at that
temperature
54. When relative humidity reaches 100
percent, the air has reached saturation
pressure and cannot absorb any more water
vapor.
55. Why do high humidity levels make people
feel uncomfortable? because little or none of
their sweat can evaporate and draw heat from
their skin.
56. As air warms, the amount of water vapor
that it can hold rises exponentially.
Consequently, atmospheric water vapor
concentrations are highest in warm regions
and decrease toward the poles
Photo: Pamela R. Cox 2013 Elizabethtown, Kentucky
Atmospheric water vapor mean, 1988-1999
http://www.learner.org/courses/envsci/visual/visual.php?shortname=water_vapor_mean
57.Discuss three ways atmospheric water
vapor contributes to weather patterns.
1. adding water vapor to the air reduces its density,
so adding moisture to dry air may make it become
buoyant and rise.
2. moist air carries latent energy, the potential for
condensation of water vapor to heat the air.
3. When an air parcel cools to its dew point, water
vapor begins condensing and forming cloud
droplets or ice crystals, which may ultimately
grow large enough to fall as rain or snow.
58. Define latent energy.
the potential for condensation of water vapor
to heat the air
59.Define dew point.
denotes the temperature to which air would
have to cool to reach 100 percent relative
humidity
60.Explain what determines whether
atmospheric conditions can be stable
or unstable.
How quickly the temperature of the
environment declines with altitude
determines stability of the
atmosphere. An unstable atmosphere is
more likely to produce clouds and
storms than a stable atmosphere
Photo: Pamela R. Cox 2013 Elizabethtown, Kentucky
Conditional instability
http://www.learner.org/courses/envsci/unit/pdfs/unit2.pdf
61. Convection is not the only process that
lifts air from lower to higher altitudes.
When winds run into mountains and are
forced upward the air cools, often forming
clouds over windward slopes and the crests
of hills.
Photo: Pamela R. Cox 2013 Elizabethtown, Kentucky
62. Define and explain convergence.
Convergence occurs
when air masses run
together, pushing air
upward generating
thunderstorms.
And when warm and
cold air fronts
collide, the denser
cold air slides
underneath the warm
air layer and
lifts it.
Photo: Pamela R. Cox 2013 Elizabethtown, Kentucky
63. Compare and contrast low-altitude
clouds with high-altitude clouds
Low-altitude clouds emit and absorb infrared
radiation much as the ground does, so they are
roughly the same temperature as Earth's
surface and thus do not increase atmospheric
temperatures.
High-altitude clouds tend to be thinner, so
they do not reflect significant levels of
incoming solar radiation. They efficiently
absorb outgoing thermal radiation and warm
the atmosphere, and they radiate heat back to
the surface.
Photo: Pamela R. Cox 2013 Elizabethtown, Kentucky