1. Miscellaneous Measurements
Humidity Measurements
Dr.Mohammed Abdulrazzaq
Mechanical Department
College of Engineering

2. ASSIGNMENT – 10 POINTS
WRITE A 1 TO 2 PAGE REPORT ON “THE IMPACT OF THE TRI-STATE TORNADO IN ILLINOIS”
DUE IN ONE WEEK

3. WATER SOURCES OCEANS ICE SHEETS & GLACIERS GROUNDWATER LAKES
ATMOSPHERE
STREAMS

4. HYDROLOGIC CYCLE
ALSO KNOWN AS WATER CYCLE

6. WATER MOVING FROM EARTH TO ATMOSPHERE
EVAPORATION - WATER CHANGES FROM LIQUID TO VAPOR
TRANSPIRATION - WATER TAKEN UP THROUGH PLANT ROOTS

7. SUBLIMATION - WATER CHANGES FROM SOLID TO VAPOR
EVAPOTRANSPIRATION - SUM TOTAL OF EVAPORATION & TRANSPIRATION TOGETHER

8. WATER MOVES FROM ATMOSPHERE TO EARTH
CONDENSATION - WATER CHANGES FROM VAPOR TO LIQUID
DEPOSITION - WATER CHANGES FROM VAPOR TO SOLID
PRECIPITATION

9. HUMIDITY AMOUNT OF WATER VAPOR IN THE AIR
DOG DAYS OF SUMMER - COMBINATION OF HEAT & HUMIDITY FROM MID-JULY THROUGH MID-AUGUST

10. SPECIFIC HUMIDITY ALSO KNOWN AS THE MIXING RATIO
DESCRIBED AS THE MASS (WEIGHT) OF WATER VAPOR PER MASS OF DRY AIR
GRAMS (WATER) / KILOGRAM OF AIR G/KG

11. RELATIVE HUMIDTY
% OF THE MAXIMUM AMOUNT OF WATER VAPOR (SATURATION) THAT AN AIR SAMPLE CAN HOLD (KEEP IN SUSPENSION) AT A GIVEN TEMPERATURE
CAN CHANGE WHEN EITHER THE TEMPERATURE OR THE AMOUNT OF WATER VAPOR CHANGES

12. WITH NO CHANGE IN WATER VAPOR CONTENT
AS THE TEMPERATURE INCREASES THE RELATIVE HUMIDITY WILL GO DOWN
AS THE TEMPERATURE DECREASES THE RELATIVE HUMIDITY WILL GO UP

13. MAXIMUM WATER VAPOR PER TEMPERATURE

14. RELATIVE HUMIDITY CHANGES WHEN:
DAILY TEMPERATURES CHANGE
AIR MOVES FROM ONE PLACE TO ANOTHER
AIR MOVES UP OR DOWN IN THE ATMOSPHERE

16. SATURATION WHEN THE RELATIVE HUMIDITY IS 100% FOR A GIVEN TEMPERATURE
IF THE AIR IS LESS THAN 100% RELATIVE HUMIDITY IT IS UNSATURATED AIR
IF THE AIR IS ABOVE 100% RELATIVE HUMIDITY IT IS SUPERSATURATED

17. DEW POINT TEMPERATURE
TEMPERATURE AT WHICH SATURATION OCCURS FOR A SPECIFIC AMOUNT OF WATER VAPOR
AS THE AMOUNT OF WATER VAPOR CHANGES SO DOES THE DEW POINT TEMPERATURE

18. RELATIVE HUMIDITY MEASURING INSTRUMENTS
SLING PSYCHROMETER
HAIR HYGROMETER
HYGROGRAPH

21. LIFTING CONDENSATION LEVEL - LCL
THE ALTITUDE TO WHICH AN AIR PARCEL WOULD NEED TO BE LIFTED FOR CONDENSATION TO OCCUR
VISIBLE EVIDENCE IS THE CLOUD BASE
OCCURS AT SATURATION/DEW POINT TEMPERATURE

22. DRY ADIABATIC LAPSE RATE (DALR)
TEMPERATURE DECREASE EXPERIENCED BY A RISING UNSATURATED PARCEL – ABOUT 1 DEGREE CELSIUS PER 100 METERS OR 10 DEGREES/1000 METERS
SINKING PARCELS WARM AT THE SAME RATE

23. DALR

24. DALR PROBLEM
THE SURFACE TEMP IS 20 DEGREES C & THE DEW POINT IS 5 DEGREES C, HOW MANY METERS MUST THE AIR RISE TO REACH THE LCL?
ANSWER: 15 DEGREES X 100 METERS = 1500 METERS OR 1.5 KILOMETERS

25. WET ADIABATIC LAPSE RATE
RATE OF TEMPERATURE CHANGE FOR A RISING SATURATED PARCEL OF AIR
ON THE AVERAGE IT IS ABOUT 5 DEGREES C/ 1000 METERS

27. WALR PROBLEM
AT THE SURFACE THE TEMP IS 25 DEGREES C AND THE DEW POINT IS AT 15 C, WHAT WILL THE TEMP BE AT 4000 METERS ABOVE THE SURFACE?
ANSWER: 0 CELSIUS – [25 – (DALR = 10 DEGREES/1000 METERS) = 15] 15 – (WALR = 5 DEGREES/1000 METERS) = 15 {15 – 15 = 0}

28. EFFECTS OF VERTICAL MOVEMENT OF AIR
WHEN AIR RISES IT EXPANDS AND COOLS. AS IT COOLS, ITS RELATIVE HUMIDITY GOES UP
WHEN AIR SINKS IT IS COMPRESSED AND WARMED. AS IT WARMS ITS RELATIVE HUMIDITY(RH) GOES DOWN
RATE DEPENDS ON THE AIR’S RH

29. Thank You for Your Attention!