Transcript WATER IN THE ATMOSPHERE

WATER IN THE ATMOSPHERE
CHAPTER 18.1 HUMIDITY AND
CONDENSATION
CHARACTERISTICS OF WATER
DO NOT WRITE
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WATER IS UNIQUE BECAUSE IT EXISTS
IN ALL THREE PHASES OF MATER IN
NATURE
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SOLID – 00C OR BELOW
LIQUID – 00C – 1000C
GAS – 1000C OR ABOVE – WATER VAPOR
AN INVISIBLE GAS
EVAPORATION
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CHANGE FROM LIQUID TO GAS
ABSORBS HEAT
COOLING PROCESS
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EX. SWIMMING POOL OR SWEATING
H2O MOLECULES ABSORB HEAT FROM
YOUR BODY
CONDENSATION
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CHANGE FROM GAS TO LIQUID
RELEASES HEAT
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EX. GLASS OF WATER IN FREEZER
TYPES OF CONDENSATION
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DEW
FOG
CLOUDS
DEPOSITION AND SUBLIMATION
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CHANGE FROM
VAPOR DIRECTLY TO
SOLID
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FROST
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CHANGE FROM SOLID
DIRECTLY TO A
VAPOR
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SNOWBANK
MELTINGWITH
FREEZING REMPS
DEPOSITION (Heat released)
ICE
(snow, hail, frost)
FREEZING
CONDENSATION
MELTING
EVAPORATION
LIQUID WATER
(clouds, rain, dew)
Heat
released
Heat absorbed
SUBLIMATION (Heat absorbed)
WATER VAPOR
(invisible)
HUMIDITY
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AMT OF WATER VAPOR IN THE AIR VARIES
WIDELY
SPECIFIC HUMIDITY IS THE NUMBER OF
GRAMS OF WATER VAPOR IN A Kg OF AIR AT A
GIVEN TIME OR LOCATION
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WARM AIR CAN HOLD MORE MOISTURE THAN
COLD AIR
SATURATED AIR OCCURS WHEN EVAPORATION
RATE EQUALS CONDENSATION RATE EX. LID
ON CUP
RELATIVE HUMIDITY
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AMOUNT OF WATER VAPOR IN THE AIR
COMPARED TO THE AMOUNT THE AIR
CAN HOLD AT A GIVEN TEMPERATURE
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RH = SPECIFIC HUMIDITY X 100
MAXIMUM CAPACITY
PSYCHROMETER – MEASURES HUMIDITY
CONDENSATION
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THE TEMPERATURE AT WHICH SATURATION
OCCURS AND CONDENSATION BEGINS IS
CALLED THE DEW POINT
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IT IS A MEASURE OF THE AMOUNT OF WATER
VAPOR IN THE AIR
EX. WARM DAY AND COLD NIGHT
COOLING AND CONDENSATION
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TWO CONDITIONS NECESSARY FOR
CONDENSATION
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1. MATERIAL TO CONDENSE ON
(CONDENSATION NUCLEI SALT,
SULFATES OR NITRATES)
2. AIR TEMP AT DEW POINT
AIR MAY COOL OR LOSE HEAT BY:
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CONTACT WITH COLDER SURFACE
RADIATION OF HEAT
MIXING WITH COLDER AIR
EXPANSION AS IT RISES
FORMATION OF FROST AND DEW
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FORM WHEN MOIST AIR CONTACTS COOL
SURFACES AND DEW POINT TEMP IS
REACHED
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BELOW 00C = FROST
FORMATION OF FOG / CLOUDS
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FORM WHEN A COLD
SURFACE CONTACTS
WARMER MOIST AIR
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THE SLIGHTEST AIR
MOVEMENTS KEEP
THE TINY DROPLETS
OF WATER
SUSPENDED
RADIATION FOG
(DO NOT WRITE)
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FORMS WHEN THE
NIGHT SKY IS CLEAR
GROUND LOSES HEAT
RAPIDLY
LIGHT WINDS MIX
COOLER BOTTOM AIR
WITH WARMER TOP AIR
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DEW POINT IS REACHED
FOG IS COLDER THAN AIR
ABOVE IT
TEMPERATURE INVERSION
ADVECTION FOG
(DO NOT WRITE)
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FORM WHEN WARM MOIST AIR BLOWS
OVER A COOL SURFACE
IN U.S. AND CANADA, FORM WHEN
WARM MOIST SOUTHERLY WIND MOVES
OVER SNOW COVERED GROUND
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NEWFOUNDLAND FOG
WINTER FOGS - MISSISSIPPI