= saturation specific humidity saturation: represents the...
TRANSCRIPT
Temp qsat Temp qsat
5°C 5.6 g/kg 25°C 20 g/kg
10°C 7.7 g/kg 30°C 28 g/kg
15°C 11 g/kg 40°C 47 g/kg
20°C 15 g/kg 50°C 80 g/kg
qSAT = saturation specific humidity SATURATION:
Represents the maximum amount of water vapor that can exist in air for a given temperature and pressure.
@ sea level pressure
T=20°C qsat = 15 g/kg q = 7.5 g/kg RH = 50%
T=20°C qsat = 15 g/kg q = 7.5 g/kg RH = 50%
T=10°C qsat = 7.7 g/kg q = 7.5 g/kg RH = 97%
Cool to 10°C
T=20°C qsat = 15 g/kg q = 7.5 g/kg RH = 50%
T=9.5°C qsat = 7.5 g/kg q = 7.5 g/kg
Cool to 9.5°C
NOW LET’S COOL THE AIR EVEN FURTHER:
T=20°C qsat = 15 g/kg q = 7.5 g/kg RH = 50%
T=9.5°C qsat = 7.5 g/kg q = 7.5 g/kg RH = 100%
Cool to 9.5°C
NOW LET’S COOL THE AIR EVEN FURTHER:
T=20°C qSAT = 15 g/kg q = 7.5 g/kg RH = 50%
T=9.5°C qsat = 7.5 g/kg q = 7.5 g/kg RH = 100% TDEW = 9.5°C
Cool to 9.5°C
NOW LET’S COOL THE AIR EVEN FURTHER:
Dew Point Temperature (TDEW): Temperature to which air must be cooled to reach saturation.
When air is at TDEW, the RH=100%
T=20°C qsat = 15 g/kg q = 7.5 g/kg RH = 50%
T=9.5°C qsat = 7.5 g/kg q = 7.5 g/kg RH = 100%
T=0°C qsat = 3.5 g/kg q = 3.5 g/kg RH = 100%
Cool to 9.5°C
Cool to 0°C
WHAT IF WE COOL THE AIR BELOW TDEW:
T=20°C qsat = 15 g/kg q = 7.5 g/kg RH = 50%
T=9.5°C qsat = 7.5 g/kg q = 7.5 g/kg RH = 100%
T=0°C qsat = 3.5 g/kg q = 3.5 g/kg RH = 100%
Cool to 9.5°C
Cool to 0°C
4 g liquid water for each kg air
WHAT IF WE COOL THE AIR BELOW TDEW:
Clicker Question
Air Dew Point City Temperature Temperature City A 95°F 75°F City B 50°F 42°F City C 30°F 21°F City D 10°F 10°F Which city has the highest relative humidity? (A) City A (B) City B (C) City C (D) City D
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Clicker Question
Air Dew Point City Temperature Temperature City A 95°F 75°F City B 50°F 42°F City C 30°F 21°F City D 10°F 10°F Which city has the highest relative humidity? (A) City A (B) City B (C) City C (D) City D
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Pacific Ocean
Gulf of Mexico
San Diego Water Temp = 60°F New Orleans
Water Temp = 80°F
Pacific Ocean
Gulf of Mexico
San Diego Water Temp = 60°F
New Orleans Water Temp = 80°F
Pacific Ocean
Gulf of Mexico
San Diego Water Temp = 60°F
New Orleans Water Temp = 80°F
AT BOTH LOCATIONS SAN DIEGO NEW ORLEANS During day, land warms to 85°F but ocean temp does not change
Pacific Ocean
Gulf of Mexico
San Diego Water Temp = 60°F
New Orleans Water Temp = 80°F
AT BOTH LOCATIONS SAN DIEGO NEW ORLEANS During day, land warms to 85°F Twater = 60°F but ocean temp does not change Tland = 85°F
Pacific Ocean
Gulf of Mexico
San Diego Water Temp = 60°F
New Orleans Water Temp = 80°F
AT BOTH LOCATIONS SAN DIEGO NEW ORLEANS During day, land warms to 85°F Twater = 60°F Twater = 80°F but ocean temp does not change Tland = 85°F Tland = 85°F
Pacific Ocean
Gulf of Mexico
San Diego Water Temp = 60°F
New Orleans Water Temp = 80°F
AT BOTH LOCATIONS SAN DIEGO NEW ORLEANS During day, land warms to 85°F Twater = 60°F Twater = 80°F but ocean temp does not change Tland = 85°F Tland = 85°F Air over water near saturation RH = 100% RH = 100%
Pacific Ocean
Gulf of Mexico
San Diego Water Temp = 60°F
New Orleans Water Temp = 80°F
AT BOTH LOCATIONS SAN DIEGO NEW ORLEANS During day, land warms to 85°F Twater = 60°F Twater = 80°F but ocean temp does not change Tland = 85°F Tland = 85°F Air over water near saturation RH = 100% RH = 100%
@ 60°F, qsat=11 g/kg so, q=11 g/kg
Pacific Ocean
Gulf of Mexico
San Diego Water Temp = 60°F
New Orleans Water Temp = 80°F
AT BOTH LOCATIONS SAN DIEGO NEW ORLEANS During day, land warms to 85°F Twater = 60°F Twater = 80°F but ocean temp does not change Tland = 85°F Tland = 85°F Air over water near saturation RH = 100% RH = 100%
@ 60°F, qsat=11 g/kg @80°F, qsat=22 g/kg so, q=11 g/kg so, q=22 g/kg
Pacific Ocean
Gulf of Mexico
San Diego Water Temp = 60°F
New Orleans Water Temp = 80°F
AT BOTH LOCATIONS SAN DIEGO NEW ORLEANS During day, land warms to 85°F Twater = 60°F Twater = 80°F but ocean temp does not change Tland = 85°F Tland = 85°F Air over water near saturation RH = 100% RH = 100%
@ 60°F, qsat=11 g/kg @80°F, qsat=22 g/kg so, q=11 g/kg so, q=22 g/kg
Ocean air moves inland and warms to 85°F As air moves inland, q stays the same. What is RH? @ 85°F, qsat = 25.6 g/kg
Pacific Ocean
Gulf of Mexico
San Diego Water Temp = 60°F
New Orleans Water Temp = 80°F
AT BOTH LOCATIONS SAN DIEGO NEW ORLEANS During day, land warms to 85°F Twater = 60°F Twater = 80°F but ocean temp does not change Tland = 85°F Tland = 85°F Air over water near saturation RH = 100% RH = 100%
@ 60°F, qsat=11 g/kg @80°F, qsat=22 g/kg so, q=11 g/kg so, q=22 g/kg
Ocean air moves inland and RH = (q/qsat)x100% warms to 85°F RH = (11/25.6)x100% As air moves inland, q stays RH = 43% the same. What is RH? @ 85°F, qsat = 25.6 g/kg
Pacific Ocean
Gulf of Mexico
San Diego Water Temp = 60°F
New Orleans Water Temp = 80°F
AT BOTH LOCATIONS SAN DIEGO NEW ORLEANS During day, land warms to 85°F Twater = 60°F Twater = 80°F but ocean temp does not change Tland = 85°F Tland = 85°F Air over water near saturation RH = 100% RH = 100%
@ 60°F, qsat=11 g/kg @80°F, qsat=22 g/kg so, q=11 g/kg so, q=22 g/kg
Ocean air moves inland and RH = (q/qsat)x100% RH = (q/qsat)x100% warms to 85°F RH = (11/25.6)x100% RH = (22/25.6)x100% As air moves inland, q stays RH = 43% RH = 86% the same. What is RH? @ 85°F, qsat = 25.6 g/kg
Clicker Question
During the night a cloud moves overhead. In general, how does this impact the surface (ground) temperature? (A) Has no impact on the surface temperature (B) The surface temperature will increase (C) The surface temperature will decrease
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Clicker Question
During the night a cloud moves overhead. In general, how does this impact the surface (ground) temperature? (A) Has no impact on the surface temperature (B) The surface temperature will increase (C) The surface temperature will decrease
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Clicker Question
If the night is cloudy (not fog), will the clouds help produce radiation fog? (A) Yes (B) No
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Clicker Question
If the night is cloudy (not fog), will the clouds help produce radiation fog? (A) Yes (B) No
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Radiation Fog in the San Joaquin Valley January 2004
FOG
SNOW S.F.
L.A.