Essentials of Meteorology.pdf - rodbailey blog

worth millions of dollars, and lightning takes the lives of
about eighty people in the United States and starts fires
that destroy many thousands of acres of valuable timber
(see Fig. 1.16).
Even the quiet side of weather has its influence.
When winds die down and humid air becomes more
tranquil, fog may form. Heavy fog can restrict visibility
at airports, causing flight delays and cancellations. Every
winter, deadly fog-related auto accidents occur along
our busy highways and turnpikes. But fog has a positive
side, too, especially during a dry spell, as fog moisture
collects on tree branches and drips to the ground, where
it provides water for the tree’s root system.
Weather and climate have become so much a part
of our lives that the first thing many of us do in the
morning is to listen to the local weather forecast. For this
reason, many radio and television newscasts have their
own “weather person” to present weather information
and give daily forecasts. More and more of these people
are professionally trained in meteorology, and many stations
require that the weathercaster obtain a seal of
approval from the American Meteorological Society
(AMS), or a certificate from the National Weather Association
(NWA). To make their weather presentation as
up-to-the-minute as possible, an increasing number of
stations are taking advantage of the information provided
by the National Weather Service (NWS), such as
computerized weather forecasts, time-lapse satellite pictures,
and color Doppler radar displays.
For many years now, a staff of trained professionals
at “The Weather Channel” have provided weather information
twenty-four hours a day on cable television.
And finally, the National Oceanic and Atmospheric Administration
(NOAA), in cooperation with the National
Weather Service, sponsors weather radio broadcasts at
selected locations across the United States. Known as
Summary
This chapter provided an overview of the earth’s atmosphere.
Our atmosphere is one rich in nitrogen and oxygen
as well as smaller amounts of other gases, such as
water vapor, carbon dioxide, and other greenhouse gases
whose increasing levels may result in global warming.
We examined the earth’s early atmosphere and found it
to be much different from the air we breathe today.
We investigated the various layers of the atmosphere:
the troposphere (the lowest layer), where almost
Summary 21
FIGURE 1.16
Estimates are that lightning strikes the earth about 100 times
every second. Consequently, it is a very common, and
sometimes deadly, weather phenomenon.
NOAA weather radio (and transmitted at VHF–FM frequencies),
this service provides continuous weather
information and regional forecasts (as well as special
weather advisories, including watches and warnings)
for over 90 percent of the nation.
all weather events occur, and the stratosphere, where
ozone protects us from a portion of the sun’s harmful
rays. Above the stratosphere lies the mesosphere, where
the air temperature drops dramatically with height.
Above the mesosphere lies the warmest part of the
atmosphere, the thermosphere. At the top of the thermosphere
is the exosphere, where collisions between
gas molecules and atoms are so infrequent that fastmoving
lighter molecules can actually escape the earth’s