(click here to download this study guide in Microsoft
WORD format)
Questions
on Quiz #1 will come
from topics on this study guide together with material on the Practice
Quiz Study Guide.
***
Chap. 1 (pps 14-19), Chap. 4 (pps 93-100) ***
Mass, weight,
density, and
pressure. Mass is the amount of a
particular substance. On the earth gravity pulls downward on a mass
producing weight. Pressure at any level in the atmosphere is a
measure of the weight of the air above (this is one way of thinking
about and understanding pressure). Pressure is defined as force
divided by area and acts like a force (a force that pushes upward,
downward, and sideways). Common pressure units and typical sea level
pressure values. What instrument is used to measure air pressure?
About when was it invented? Pressure and air density (density = mass
divided by volume) both decrease with increasing altitude (you should
be able to explain why). What relationship is there between the rate
of pressure decrease and air density (i.e. does pressure decrease
most rapidly in high or low density air)?
Layers of the atmosphere.
Troposphere: lowest layer in the
atmosphere, decreasing temperature with increasing altitude (why is
the warmest air found near the ground), contains most of the water
vapor and clouds, can be unstable (strong vertical air motions
possible). Tropopause. Stratosphere: isothermal layer and
temperature inversion layer (what causes the warming in the
stratosphere), stable layer, contains the ozone layer. Approximate
altitudes of these layers. Units: meters, kilometers, feet, miles.
Ideal Gas Law.
This is
a
microscopic-scale explanation of air pressure. Two equations:
P = N k T / V and P = (rho) R
T. N is the number of air molecules in
a
volume V, T is temperature and rho
is density. R and k are both constants. You
should be able to determine what will happen to the
pressure in a rigid container or something flexible like a balloon if
you change
the variables in the
equation above. What variables could you change together in such
a way
that the pressure
would stay constant?
Ideal gas law
applications. If you heat or cool a parcel of air in the
atmosphere, Charles' law says the density
(volume)
will change in such a way that the air pressure inside the parcel
remains constant (remains the same as the pressure of the air
surrounding the parcel).
***
Chap. 1 (pps 21-26), Appendix C (pps 525-529) ***
Station model notation.
How and where are the following weather variables plotted: cloud cover,
temperature, dew point temperature (typical values for
Tucson), wind direction and speed, common weather symbols (rain, snow,
fog, rain shower, thunderstorm, tropical storm and hurricane),
pressure. Units. After pressure is measured, what important
adjustment
is made before the pressure is plotted on the surface map? Why is that
necessary? Average and typical range of sea-level pressure values.
Surface weather maps.
A new map is prepared hourly. What
time zone or time reference is used? 24-hour clock (what time is it
when it is 17:30 MST in Tucson). Isobars and isotherms. Small
horizontal
differences in pressure cause the wind to blow. Air motions around high
and low pressure centers (northern hemisphere). Strong and weak
pressure gradients. Convergence and divergence. Rising and sinking air
motions. How do wind motions around highs and low affect the
temperature pattern? Cold fronts and warm fronts (where is the warm and
cold air, what direction are the fronts moving).
Upper level charts (time permitting)
Ridges
(warm air below) and troughs (cold air below). Winds blow parallel to
contour lines and from west to east.
How can upper level convergence
or divergence affect surface pressure to increase or
decrease?
Is upper level convergence or divergence needed to cause a hurricane to
intensify?