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

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

WATER SOURCES OCEANS ICE SHEETS & GLACIERS GROUNDWATER LAKES ATMOSPHERE STREAMS

HYDROLOGIC CYCLE ALSO KNOWN AS WATER CYCLE

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

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

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

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

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

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

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

MAXIMUM WATER VAPOR PER TEMPERATURE

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

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

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

RELATIVE HUMIDITY MEASURING INSTRUMENTS SLING PSYCHROMETER HAIR HYGROMETER HYGROGRAPH

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

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

DALR

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

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

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}

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

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