Transcript Weather-all-in-one-1 - At Ballakermeen we`ll take you there

Weather
Whether the weather be fine,
Or whether the weather be not,
Whether the weather be cold,
Or whether the weather be hot,
We'll whether the weather
Whatever the weather
Whether we like it or not.
What’s it made of?
 The atmosphere is a
mixture of transparent
gases held to the Earth
by its gravitational force.
 It consists of mainly
nitrogen (78.09%) and
oxygen (20.95%) by
volume.
 Other gases include
argon, carbon dioxide,
water vapour containing
hydrogen, neon, helium,
krypton, xenon, ozone,
methane and radon.
(How many of those can
you remember?)
The Upper Atmosphere
 By international convention the top of the upper
atmosphere is assumed to be at 1000km, but due to
gravity and compression, most of the atmosphere is
concentrated near to the earth’s surface.
 About 50% lies within 5.6km of the surface and 99%
within 40km.
 You’ll be ready for University Challenge after this ...
The Troposphere
 NB: This is the important
bit!
 Most of our climate and
weather processes operate
within 16-17 km of the
earth’s surface in this lower
atmospheric zone. In the
troposphere temperatures
generally decrease with
height (averaging 6.5˚C per
km).
 The top of this layer is
marked by a boundary
called the tropopause
where temperatures
remain fairly constant.
 This occurs at a height of
about 8 km at the poles
and 17 km in the tropics
and it can vary with
seasonal changes in
climate.
The Tropopause
 The tropopause acts as a temperature inversion
forming an effective ceiling to any convection in the
troposphere and so provides an upper limit to the
earth’s weather systems.
 Within the troposphere vertical convection currents
disturb the atmosphere and masses of air flow
horizontally from one latitude to another.
 These movements provide a background to the study
of climate.
The Stratosphere
 The stratosphere is the next
layer of the atmosphere
extending to about 50km
above the Earth’s surface and
within this layer
temperatures actually
increase with height.
 Within this cloud and dust
free layer, ozone absorbs and
filters out ultraviolet
radiation.
 Warming is greater over the
polar regions than in the
tropical latitudes and these
temperature differences lead
to strong horizontal air
movements at great heights.
 Global warming has been
linked to recent changes in
the stratosphere, brought
about by human activity. The
upper limit of the
stratosphere is marked by the
stratopause.
The Stratosphere Hotel, Las Vegas
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rewarded with a breathtaking
view of historic downtown Las
Vegas. Experience Insanity
and walk away to tell the tale!
Mesosphere and Thermosphere
 The final two layers of
atmosphere are shown on
this diagram.
 Within the mesosphere
temperatures again
decrease with altitude.
 However, in the
atmosphere’s most distant
layer, the thermosphere,
temperatures start to rise
again at a constant rate up
to as much as 1500ºC.
The Atmospheric Heat Budget
 The earth and its atmosphere receive heat energy from
the sun. The atmospheric heat budget of the Earth
depends on the balance between incoming solar
radiation (insolation) and outgoing radiation from
the planet .
 Geological records show that, on average, the energy
budget has remained constant over the last few
thousand years. This means that the incoming and
outgoing energies must be equal. However, there is
evidence to suggest that global warming has occurred
over recent decades.
The Heat Budget continued ...
 The Earth receives energy from the sun as incoming
radiation. Some of this is lost on passing through the
atmosphere but overall the surface has a net gain of energy.
The only places where there is a deficit are the polar regions
where only about 24% of the incoming solar radiation
reaches the surface of the Earth, because of absorption,
reflection and scattering.
 The atmosphere, in contrast, has a net deficit of energy. To
compensate for this difference, heat is transferred from the
surface of the Earth to the atmosphere by radiation,
conduction and by the release of latent heat.
More Heat Budget stuff ...
 There are variations in energy
and heat between different
latitudes. Low latitudes have
a net surplus of energy, due
mainly to their relative
proximity to the sun.
 The high latitudes (polewards
40N and 40S) have a net
deficit.
 Theoretically, this differential
heating should result in the
equatorial regions being
much hotter and the poles
much colder than they are.
 Since the poles are not
becoming colder, and the
equatorial regions are not
becoming hotter, heat must
be being transferred between
the two. This occurs by
means of air movement
(winds), and water
movement (ocean currents).
Planetary Surface Winds
 Wind is the horizontal movement of air on the Earth’s surface.
 Winds result from differences in air pressure and they always blow
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from high to low pressure.
Pressure differences occur spatially because of global and local
variations in temperature.
When the air temperature of a place increases, the air in that area
expands and rises, thus reducing air pressure.
Conversely, when the temperature falls, the air becomes denser, it sinks
and air pressure increases.
The gradual change in air pressure over an area, seen in the pattern of
isobars on a weather map, is called the pressure gradient.
This gives rise to the movement of air from an area of relatively high
pressure to an area of relatively low pressure.
That Wind Chill Factor ...
 Winds can also have a
marked influence on
temperatures; the
temperature of the wind
is influenced by its area
of origin and by the
characteristics of the
surface over which it has
travelled.
 Generally, winds blowing
onto the land from the
sea tend to relatively
warm in winter and help
to raise air temperatures.
In the summer onshore
winds tend to depress air
temperatures as the sea
over which the wind has
travelled is much cooler
than the land surface.
Furry Bear
If I were a bear, and a big bear too,
I shouldn't much care, if it froze or snew;
I shouldn't much mind, if it snowed or frizI'd be all fur-lined,with a coat like his!
For I'd have fur boots and a brown fur wrap,
And brown fur knickers and a big fur cap.
I'd have a fur muffle-ruff to cover my jaws.
And brown fur mittens on my big brown paws.
With a big brown furry-down up to my head,
I'd sleep all the winter in a big fur bed.