Climatology and Meteorology
Some types of thermometers:
- liquid-in glass
- bimetallic
Mercury barometer has a bowl with liquid in it and a
tube sealed at the top and open at the bottom immersed in the liquid. When pressure rises, the mercury in the tube
rises.
Thermometers
Thermometers
measure temperature.
Some types of thermometers:
- liquid-in glass
- bimetallic
- infrared
thermoelectric
Liquid in Glass Thermometer
Most common for
everyday use (medicine, cooking, etc.)
Liquid is either
mercury or alcohol
Difficult to
automate – led to development of other thermometers
Bimetallic Thermometer
Uses a coil of two
different metals attached to one another
Different metals
expand at different rates
Used in:
round outdoor thermometers
thermostats
Infrared Thermometer
Measures the
infrared radiation emitted by an object (night-vision uses it)
Used to take an
instant (not delayed) temp reading of the air.
Easily automated
- but other aspects such as ground color can affect temp readings
Thermoelectric Thermometer
Most common thermometer for automated stations
Advantages: Rugged, reliable, wide temperature range, inexpensive, and
fast response
Works by passing a known voltage through a wire who’s resistance varies
as a function of temperature.
Anemometer
Used to measure
wind speed
Most common type =
cup anemometer
When the wind is
gusty, it overestimates the avg. wind speed because of momentum
Must be placed far
away from obstacles to be accurate (Distance = 10x the height of tallest
object)
Wind Vane
Measures wind
direction
Points parallel
with the wind
Has a “fatter” tail
than head so it won’t point 180ยบ in the wrong direction.
Easily automated with a rotating sensor inside the joint with
the pole.
Barometer
Measures atmospheric pressure
Works like a weight scale for the air above it
Aneroid barometer uses gears attached to a sealed air
container that expands or contracts with decreasing or increasing pressure,
respectively.
Mercury barometer has a bowl with liquid in it and a
tube sealed at the top and open at the bottom immersed in the liquid. When pressure rises, the mercury in the tube
rises. Rain Gauge
Several kinds but tipping bucket rain
gauge is the most useful since it can be automated.
How it works:
- Rain falls into one of two buckets
- When
it’s fills up with .01” of rain,
gravity causes it to tip
- Other bucket fills and tips
- Number of tips counted electronically
Other instruments
Many other instruments are used such as a hygrometer which measures
humidity.
There are other instruments to collect data that we will discuss later
(radar, satellites, and rawindondes)
In METR 3613 “Meteorological Instruments” you will learn MUCH more about
this subject.
Networks
Networks are used to collect mass quantities of weather data. (most are stationary)
ASOS Network (Automated Surface Observation System) – nationwide network
for measuring weather conditions every hr.
Oklahoma Mesonet – unique to Oklahoma, dense network of weather stations
in entire state, measuring conditions every 15 min.
View of a Typical Mesonet Station
