Download Meteorological Instruments

Meteorological Instruments
SLC Module D5
RECORDING THERMOMETER
-IDENTIFY AND KNOW PURPOSEThe bimetallic coil
contracts and expands with
changes in temperature
which causes the pen to
move accordingly.
The timer drum moves around
slowly so that a week of
temperature recordings can be
made by the pen on the
circular paper chart.
SOIL THERMOMETER
-IDENTIFY AND KNOW PURPOSEThe soil thermometer
consists of a strip of two
metals (e.g., brass and
steel) which have
different expansion rates
when heated. Because
they are connected
lengthwise, this
differential expansion of
one metal vs. the other
causes the strip to coil or
bend, and this movement
is registered by the
pointer on the dial.
SOIL THERMOMETER
-IDENTIFY AND KNOW PURPOSE-
The soil thermometer
is typically inserted 4
inches into soil where
it instantaneously reads
the temperature of the
soil.
VOLTMETER WITH
THERMOCOUPLE
-IDENTIFY AND KNOW PURPOSE-
The two small wires, when paired,
form a “thermocouple”, and
measuring the voltage difference
across the two wires yields a
temperature measurement when
you convert voltage to Celsius (can
be done using a standard table).
VOLTMETER WITH
THERMOCOUPLE
-IDENTIFY AND KNOW PURPOSE-
Thermocouples are commonly used
in research and industry because
they are accurate, cheap, and
extremely durable. They can be
used in relatively corrosive and/or
extreme temperature applications.
MINIMUM-MAXIMUM
THERMOMETER
-KNOW HOW TORead Current Temperature, Read Maximum
and Minimum Temperatures.
MINIMUM-MAXIMUM
THERMOMETER
The probe is meant to
be used under
normal, non-extreme
conditions
The tip of the probe
contains a thermistor
which consists of an
electrical resistor that
changes resistance
based on temperature.
This change is
transduced into the
temperature reading
on the LED display.
MINIMUM-MAXIMUM
THERMOMETER (Readout)
Current Temperature:
Ambient with Probe attached
Record of
Maximum
Reading
Record of
Minimum
Reading
Alarm Control
Normal/Alarm Mode Selector
MINIMUM-MAXIMUM
THERMOMETER (rear control panel)
In Normal Display Mode
Use to reset either MIN or MAX
Fast
Sampling
Rate =
10 sec
Normal
Sampling
Rate =
60 sec
Select
Temp Scale
Displayed
In Alarm Display Mode
Use to reset either LO or HI
MINIMUM-MAXIMUM
THERMOMETER (reset unit)
Insert a slender object and push RESET gently.
Necessary to do this whenever a change is made between
oC/oF, FAST/NORMAL, Probe inserted/removed.
Note that
HI/LO alarm
settings
and
MIN/Max
readings
will
be cleared!
YSI TELE-THERMOMETER WITH
PROBE
-KNOW HOW TO- Identify and Operate
The YSI Tele-Thermometer
also uses a thermistor probe
for measuring temperature.
This measurement device is
the analog version (or older
version) of the MinimumMaximum Thermometer, and
it just indicates the current
temperature without recording
previously measured Min or
Max temperatures.
YSI TELE-THERMOMETER WITH
PROBE
-KNOW HOW TO- Identify and Operate
The probe cannot
be submerged or
placed in corrosive
environments.
YSI TELE-THERMOMETER WITH
PROBE
-Taking a Reading
Start to take a
reading by turning
the knob to the
port # the probe is
inserted in (in this
picture, #1)
YSI TELE-THERMOMETER WITH
PROBE
-Taking a Reading
Then, turn the
knob to the
minimum part of
the 10°C range
the probe is
measuring
For example, if the
temperature the
probe is measuring
is 23°C, then the
knob should be
turned to “20°”,
and the pointer will
point to “3”
YSI TELE-THERMOMETER WITH
PROBE
-Taking a Reading
If the temperature the
probe is measuring is
23°C, the pointer will
point beyond 11
when the knob is set
to “0°”or “10°”,
indicating that you’ve
set the knob too low
and the actual
temperature is higher.
The pointer will point
to 0 or farther left
when the knob is set
to “30°” or “40°” and
the actual
temperature is 23°C.
RADIOTRANSMITTER
-IDENTIFY AND KNOW PURPOSE-
The transmitter emits
sound pulses (‘chirps’) at a
particular wavelength, and
the frequency of the pulses
is correlated with
temperature. Thus, you can
measure the temperature of
things remotely by tracking
the frequency of emitted
pulses with a receiver
when the transmitter is
inside something or glued
onto something, etc.
Temperature (°C)
# Chirps Per Minute
THERMOHYGROGRAPH
-KNOW HOW TORead Relative Humidity and Temperature for Given
Time and Day and Convert to OC.
[OF-32] X 5/9 = OC
[OC X 9/5] + 32 = OF
THERMOHYGROGRAPH
A length of hair (typically
blonde human or horse
hair) expands or contracts
in reaction to changes in
humidity. The hair is
connected to one end of a
pen arm through a series
of levers, and the
expansion or contraction
causes the pen to move up
or down with respect to
humidity changes.
A bimetallic coil consists
of 2 joined metals that
expand or contract slightly
differently from each other
when temperature
increases or decreases,
respectively. These
relative changes in the
metals cause the coil to
expand or contract and
make the pen move up or
down accordingly to
indicate temperature
changes.
THERMOHYGROGRAPH
(Details of chart recorder)
The drum can be wound
to make one complete
revolution over the length
of 1 week
Temperature Scale
Relative Humidity
Scale
The top strip records
the measured
temperature in °F for
one week.
The bottom strip records
the measured relative
humidity in % for one
week.
Example Thermohygrograph Chart
AU
70
THERMOHYGROGRAPH
(Details of chart recorder)
Temperature Scale
Note that the
temperature scale is
in °F. Be aware that
you may need to
convert to °C.
°C = 5/9 x (°F – 32)
°F = (9/5 x °C) + 32
BENDIX PSYCHROMETER
-KNOW HOW TORead Wet and Dry Bulb Temperatures and, from the TRe
Diagram, Determine % Relative Humidity and Dew Point
Temperature
BENDIX PSYCHROMETER
Please Note:
The Wet and Dry Bulb Thermometers are on the side
(instead of the top) of the new Bendix Psychrometer.
BENDIX PSYCHROMETER
Wet Bulb Thermometer (covered in cloth sleeve that can be wetted)
Dry Bulb Thermometer
The Bendix Psychrometer
has an internal fan that is
turned on by rotating the
knob clockwise one click.
The benefit of the internal
fan is that the device can be
used to measure humidity in
enclosed spaces.
BENDIX PSYCHROMETER
The Wet Bulb Thermometer measures the
temperature reached after forced evaporation from
the wick. The fan creates air movement which
speeds up evaporation. Drier air results in lower
wet bulb temperatures.
The Dry Bulb
Thermometer measures
ambient temperature.
Taking a Reading:
1. Wet the sleeve of the wet bulb thermometer
2. Turn knob clockwise to turn on fan. Leave Bendix Psychrometer
standing upright so that fan does not hit the sides of the device.
3. Leave fan on until wet bulb temperature has stabilized (~1 minute)
Taking a Reading:
4. Record the value of the Wet Bulb and Dry Bulb Thermometers.
5. Turn off fan by rotating the knob clockwise one click.
Psychrometric Slide Rule
Taking a Reading:
1. Now use a Psychrometric Slide Rule to convert Wet Bulb and Dry
Bulb Temperature readings into Relative Humidity.
2. Line up the Wet Bulb and Dry Bulb Temperatures on the left-hand
side.
3. Then look over to the right-hand side at where the arrow points on
the “Per Cent Relative Humidity” scale.
Wet Bulb reading = 15.0oC
Dry Bulb reading = 22.5oC
Relative Humidity = 43%
TRe Diagram
You could alternatively use a
TRe Diagram to convert Wet
and Dry Bulb Temperature
measurements into Relative
Humidity.
You can also use the TRe
Diagram to convert Dry Bulb
and Relative Humidity
measurements into the Dew
Point Temperature.
TRe Diagram
Constant Relative Humidity
curved lines
Constant Temperature vertical
lines
Constant Vapor Pressure
horizontal lines
*Note that the “100% sat curve”
is the curved line for Dew Point.
To find Relative Humidity,
take your Wet Bulb
Temperature, for example,
70°F, and follow that vertical
temperature line up to the
“100% sat curve”.
Then go from the point of
intersection downward and to the
right – parallel with the black
guide lines – until you hit the
Dry Bulb Temperature vertical
line at, for example, 80°F.
Finally, read the curved
Relative Humidity line at the
point of intersection which,
in this example, is 60%.
Another Example: Your Wet
Bulb Temperature is 15°C.
If your Dry Bulb Temperature is
25°C, then your Relative
Humidity is…
31%.
Dew Point: To obtain the Dew
Point, start with the measured
Dry Bulb Temperature, for
example, 80°F. Move up
vertically along the Dry Bulb
Temperature line until it
intersects with the measured
Relative Humidity curved line,
for example, 60%.
Then move horizontally to the left
along a line of constant vapor
pressure until you hit the curved
“100% sat curve”.
Drop straight down to the x-axis,
and this value is the Dew Point in
°F or °C. In this example, 64 °F.
SLING PSYCHROMETER
-KNOW HOW TOIdentify
The Sling Psychrometer is a
method of measuring Wet and Dry
Bulb Temperature, and, hence,
Relative Humidity and Dew Point,
that does not require a battery.
Dry Bulb
Wet Bulb
The thermometers have been
removed from the example Sling
Psychrometer in the SLC, but the
essential principles of its function
were demonstrated already for the
Bendix Psychrometer.
The Sling Psychrometer cannot be used in enclosed
spaces because it uses a spinning, or “slinging”
motion to increase the wind speed across the Wet
Bulb and speed up evaporation.
You must wet the sleeve (or put water in the
reservoir at the base of the sleeve) before slinging
the psychrometer to obtain a Wet Bulb Temperature
measurement.
https://csdailyblog.wordpress.com/2013/09/06/phenology-at-conserve-school-part-i
Relative Humidity Pen
-IDENTIFY AND KNOW PURPOSE-
The newer relative humidity
measurement devices, like this ‘pen’,
measure humidity from a change in
capacitance due to a change in the
amount of water present.
Relative Humidity Pen
Front panel controls
Temp
Scale
Selector
HYGRO
MIN/MAX
Recall
Press once
to view and again
to return to
Current.
Top panel controls
TEMP
MIN/MAX
Recall
Press once
to view
and again
to return to
Current
temp.
POWER
On/Off
EVAPORIMETER
-IDENTIFY AND KNOW PURPOSE-
The timer drum and paper strip
allow you to record evaporation
rates over the course of a week.
Evaporation
rate through
time is recorded
via the pen.
The porous plate allows
for the measurement of
evaporation across the
plate’s surface.
RAIN GAUGE
-KNOW HOW TORead Rainfall in Inches
(and Convert to Centimeters)
Detailed View of Measurement
3.00 inches
3 in. x 2.54 cm/in. = 7.62 cm
CUP OR CONTACT
ANEMOMETER
-IDENTIFY
AND KNOW PURPOSE-
Wind rotates the cups, and
the rotations over time cause
a counter to increase. The
counter on the anemometer
in the SLC is designed to
count the number of
rotations, and hence the
wind speed, over long (e.g.,
a month, several months)
periods of time.
DWYER ANEMOMETER
-IDENTIFY
AND KNOW PURPOSE-
To measure high wind speed (>10 M.P.H.), place
your finger over the red opening at the top while
making your measurement. Try turning on the fan
and making a wind speed measurement.
The Dwyer Anemometer makes
instantaneous measurements of wind speed.
The left-side scale is for wind speeds
between 2 and 10 M.P.H. The right-side
scale is for wind speeds around 10 M.P.H. to
60 M.P.H.
Wind blowing past openings in the Dwyer
anemometer is drawn into the central, vertical
chamber causing the ball to float upward. The higher
the ball floats, the higher the wind speed.
DIGITAL HOT-WIRE
THERMOANEMOMETER
-KNOW HOW TODetermine Wind Speed
The Hot-Wire Anemometer is very
useful for measuring low wind
speeds because of its sensitivity.
However, it’s not durable enough to
use in applications where it might be
exposed to rain or particulates.
DIGITAL HOT-WIRE
THERMOANEMOMETER
After turning the instrument on,
wait for it to count-down, and
then note that it tells you the
wind speed in m/s and the
temperature in °C
DIGITAL HOT-WIRE
THERMOANEMOMETER
If you examine the head of the probe
closely you can see the “hot-wire”
part in an inlet. Do NOT touch! It’s
expensive and delicate.
The head of the probe is where the
measurements are actually made.
The body of the probe telescopes to
allow you to measure wind speeds in
vents or high in the air.
DIGITAL HOT-WIRE
THERMOANEMOMETER
By placing the head of the probe in line
with the flow of air, for example, in front
of a running fan, the Hot-Wire
Anemometer will display the wind speed
and temperature simultaneously.
The Hot-Wire Anemometer measures wind speed
by using electrical current to either
(1) heat up a small, exposed platinum or tungsten
wire, and monitor the change in wire
temperature due to wind stripping heat away
or
(2) maintain the wire at a constant temperature
and monitor the amount of current needed to
maintain that temperature through time. More
current will be needed at higher wind speeds.
LIGHT METER (GE TRIPLE RANGE)
-KNOW HOW TORead Light Intensity at Indicated Place
The light meter consists of a
sensitized selenium cell that converts
light energy into electrical voltage.
The red pointer indicates the change in
voltage and the 3 scale ranges allow for
interpreting the voltage change in light
intensity units called “footcandles”.
1 footcandle = 1 lumen/ft.2
LIGHT METER (GE TRIPLE RANGE)
-KNOW HOW TORead Light Intensity at Indicated Place
The side sliding button has 3
positions corresponding to each of the
3 scales on the dial (all scales have
the unit “footcandles”). If the button
is all the way down, read the
measurement of the red pointer on the
bottom scale (10 – 50 footcandles)
LIGHT METER (GE TRIPLE RANGE)
-KNOW HOW TORead Light Intensity at Indicated Place
If the red pointer is reading all the way
to the left, then the position of the
button is too high. If the red pointer is
all the way to the right, then the
position of the button is too low.
Experiment with taking measurements
under ambient fluorescent lighting or
turning on the desk incandescent lamp,
or covering the top of the device with
your hand and change the button
position to get a reading.
PYRHELIOMETER
-IDENTIFY AND KNOW PURPOSE-
The drum with the chart strip can be
wound so that it makes one complete
revolution over 1 week, and thus a
recording of weekly solar intensity.
Direct, shortwave solar
radiation is received through
the glass dome onto the
metallic strips inside. One
strip is coated to reflect the
incoming radiation, and the
other is painted optical black
and absorbs the incoming
radiation. The resulting
change in conformation of the
u-shaped metal joining the
plates changes the position of
the pen to indicate incident
solar intensity.