weather elements and their measuring instruments..

2. WEATHER
•WEATHER IS THE STATE OF THE EARTH’S ATMOSPHERE WITH
RESPECT TO TEMPERATURE, HUMIDITY, PRECIPITATION,
VISIBILITY, CLOUDINESS, AND OTHER FACTORS.

3. WIND SPEED
ANEMOMETER
AN INSTRUMENT WHICH MEASURES
WIND SPEED.

4. WIND
DIRECTION
WIND VANE
DEVICE THAT MEASURES THE
DIRECTION OF THE WIND. IT SPINS ON A
ROD AND POINTS IN THE DIRECTION
FROM WHICH THE WIND BLOWS. THE
PART OF THE VANE THAT TURNS INTO
THE WIND IS USUALLY SHAPED LIKE AN
ARROW. THE OTHER END IS WIDE SO IT
WILL CATCH THE SMALLEST BREEZE.

5. WIND
DIRECTION
WIND SOCK
LIGHT, FLEXIBLE CYLINDER OR CONE
MOUNTED ON A MAST TO SHOW THE
DIRECTION AND STRENGTH OF THE
WIND. WIND SOCK COMMONLY USED AT
AN AIRPORT OR CHEMICAL PLANT. THE
CONE-SHAPED BAG OPENED AT BOTH
ENDS SO THAT IT EXTENDS
HORIZONTALLY AS THE WIND BLOWS
THROUGH IT AND INDICATES THE WIND
DIRECTION BY POINTING AWAY FROM
THE WIND.

6. ATMOSPHERIC
PRESSURE
ANEROID
BAROMETER
A TYPE OF BAROMETER USED TO
MEASURE ATMOSPHERIC PRESSURE.

7. ATMOSPHERIC
PRESSURE
DIGITAL
BAROMETER
A TYPE OF BAROMETER USED TO
MEASURE ATMOSPHERIC PRESSURE.

8. ATMOSPHERIC
PRESSURE
BAROGRAPH
AN INSTRUMENT THAT CONTINUOUSLY
RECORDS AND PROVIDE A GRAPHICAL
REPRESENTATION OF ATMOSPHERIC
PRESSURE.

9. SUNSHINE
DURATION
CAMPBELL-STROKE
A GLASS SPHERE TO FOCUS THE SUN'S
RAYS TO AN INTENSE SPOT, WHICH WILL
BURN A MARK ON A CURVED CARD
MOUNTED CONCENTRICALLY WITH THE
SPHERE. AS THE EARTH ROTATES THE
POSITION OF THE SPOT MOVES ACROSS
THE CARD. WHEN THE SUN IS
OBSCURED, THE TRACE IS
INTERRUPTED. AT THE END OF THE DAY
THE TOTAL LENGTH OF THE BURN OR
TRACE, LESS GAPS, EQUALS THE
DURATION OF SUNSHINE HOURS.

10. CLOUD HEIGHT
CEILOMETER
CEILOMETER IS A DEVICE THAT USESA
LASER OR OTHER LIGHT SOURCE TO
DETERMINE THE HEIGHT OF A CLOUD
CEILING OR A CLOUD BASE FROM THE
GROUND. CEILOMETERS CAN ALSO BE
USED TO MEASURE THE AEROSOL
CONCENTRATION WITHIN THE
ATMOSPHERE.

11. EVAPORATION
EVAPORATION PAN
A TYPE OF EVAPORATION GAUGEOR
EVAPORIMETER; IT IS A PAN USED
IN THE MEASUREMENT OF
THEEVAPORATION OF WATER INTO
THE ATMOSPHERE OVER
SPECIFIEDPERIODS OF TIME.

12. HUMIDITY
HYGROMETER
AN INSTRUMENT USED TO MEASURE
THE HUMIDITY, OR AMOUNT OF
WATER VAPOUR IN THE ATMOSPHERE.
THE SENSING MECHANISM OF THE
INSTRUMENT CAN BE HAIR (HAIR
HYGROMETER), A PLATE COATED
WITH CARBON (ELECTRICAL
HYGROMETER), OR AN INFRARED
SENSOR (INFRARED HYGROMETER).

13. HUMIDITY
PSYCHROMETER
A HYGROMETER COMPOSED OF TWO
SIMILAR THERMOMETERS. THE BULB OF
ONE THERMOMETER IS KEPT WET (BY
MEANS OF A THIN, WET CLOTH WICK)
SO THAT THE COOLING THAT RESULTS
FROM EVAPORATION MAKES IT
REGISTER A LOWER TEMPERATURE
THAN THE DRY-BULB THERMOMETER.
WHEN READINGS ARE TAKEN
SIMULTANEOUSLY, IT IS POSSIBLE (WITH
THE USE OF PSYCHROMETRIC TABLES)
TO DETERMINE THE RELATIVE
HUMIDITY AND DEW- POINT
TEMPERATURE OF THE AIR.

14. TEMPERATURE &
HUMIDITY
THERMO
HYGROGRAPH
AN INSTRUMENT WHICH RECORDS THE
ENVIRONMENTAL TEMPERATURE AND
HUMIDITY AT THE SAME TIME, USUALLY
BOTH CONTINUALLY.

15. TEMPERATURE &
HUMIDITY
STEVENSON SCREEN
A STANDARD SHELTER FOR HOUSING
FOUR TYPES OF THERMOMETERS: DRY,
WET, MAXIMUM AND MINIMUM. THE
SCREEN SHIELDS THE INSTRUMENTS
FROM DIRECT SUNLIGHT.

16. TEMPERATURE
THERMOMETER
MEASURES HOW HOT OR COLD THE
ATMOSPHERE IS IN (CELSIUS (C) OR
FAHRENHEIT (F), OR KELVIN (K)). A
TRADITIONAL THERMOMETER
CONSISTS OF MERCURY, RED SPIRIT OR
GREEN SPIRIT IN A GLASS TUBE AND
OPERATES ON THE PRINCIPLE THAT THE
LIQUID EXPANDS MORE THAN THE
GLASS DOES WHEN HEATED.

17. TEMPERATURE
DRY BULB
USUALLY REFERRED TO AS ‘AIR
TEMPERATURE’. WHEN PEOPLE REFER
TO THE TEMPERATURE OF THE AIR THEY
ARE NORMALLY REFERRING TO THE
DRY BULB TEMPERATURE.

18. TEMPERATURE
WET BULB
WET BULB TEMPERATURE CAN BE
MEASURED BY USING A THERMOMETER
WITH THE BULB WRAPPED IN WET
MUSLIN. THE ADIABATIC EVAPORATION
OF WATER FROM THE THERMOMETER
BULB AND THE COOLING EFFECT IS
INDICATED BY A "WET BULB
TEMPERATURE" LOWER THAN THE "DRY
BULB TEMPERATURE" IN THE AIR . THE
EVAPORATION FROM THE WET MUSLIN
IS REDUCED WHEN AIR CONTAINS MORE
WATER VAPOR. BY COMBINING THE DRY
BULB AND WET BULB TEMPERATURE IN
A PSYCHROMETRIC CHART THE STATE
OF THE HUMID AIR CAN BE
DETERMINED.

19. RAINFALL
RAIN GUAGE
AN INSTRUMENT THAT MEASURE THE
AMOUNT OF RAIN THAT FALLS DURING
A GIVEN TIME INTERVAL USUALLY IN
MILLIMETRES OR INCHES. THE
STANDARD RAIN GAUGE TAKES THE
FORM OF A COLLECTOR ABOVE A
FUNNEL LEADING TO A RECEIVER WITH
SOME SORT OF MEASURING DEVICE.

20. RAINFALL
AUTOMATIC RAIN
GUAGE
THREE TYPES OF AUTOMATIC
PRECIPITATION RECORDERS ARE IN
GENERAL USE: THE WEIGHING
RECORDING, THE TILTING OR TIPPING-
BUCKET TYPE AND THE FLOAT TYPE.
ONLY THE WEIGHING TYPE IS
SATISFACTORY FOR MEASURING ALL
KINDS OF PRECIPITATION SUCH AS . THE
USE OF THE OTHER TWO TYPES FOR THE
MOST PART IS LIMITED TO THE
MEASUREMENT OF RAINFALL.