Meteorology

1
Meteorology
2
Todays Weather
3
Aim What is weather and the variables that
affect it?
I. Weather is the short term condition of the
atmosphere at any location.
A. Factors that affect the weather
1. Temperature specific degree of hotness or
coldness.
Freezing Point Boiling Point
32oF 212oF 0oC 100oC 273oK 373oK
4
a. Temperature is affected by amount of sunlight
(intensity and duration), different surface
materials (land or water), altitude, cloud cover,
and air mass movements.
2. Humidity dampness of the air.
a. Dew Point temperature at which air is
holding maximum amount of water vapor (gas form
of water). The air is said to be saturated with
water vapor at this temperature.
b. The ability of the air to hold water is
directly related to the temperature of the air.
5
c. The higher the temperature, the greater the
amount of water vapor the air can hold.
d. Relative Humidity is the percent of
saturation of the air. The ratio between the
actual amount of water vapor in the atmosphere
and the airs capacity at that temperature. Ex
50 relative humidity is when the air is holding
half the water vapor that it is capable of
holding.
e. Psychrometer an instrument with two
thermometers (wet and dry bulb) that can measure
both the dew point and the relative humidity of
the air.
6
Psychrometer
7
3. Air Pressure is caused by the weight of the
air.
a. Barometer instrument used to measure the air
pressure in units of mercury or millibars.
b. Standard pressure at sea level is equal to one
atmosphere (1013.2 millibars or 29.92 inches of
mercury)
c. Isobars lines of equal pressure on a weather
map.
8
Barometer
9
4. Wind the horizontal movement of air.
a. Winds are described in terms of both speed and
direction. They are named for the direction from
which they blow. Ex A north wind comes from
the north and blows towards the south.
b. Wind vane is used to indicate the direction
the wind is blowing.
c. Anemometer indicates the speed of the wind.
10
(No Transcript)
11
Anemometer