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WHAT HAPPENS TO LATENT HEAT?. SINKS OF INSOLATION. 1. SENSIBLE HEAT FLUX . Energy used in changing the temperature of the air. SINKS OF INSOLATION. 1. SENSIBLE HEAT FLUX . Energy used in changing the temperature of the air.
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SINKS OF INSOLATION • 1. SENSIBLE HEAT FLUX. Energy used in changing the temperature of the air.
SINKS OF INSOLATION • 1. SENSIBLE HEAT FLUX. Energy used in changing the temperature of the air. • 2. GROUND HEAT FLUX. Energy used in changing the temperature of the planet’s surface (continents and oceans)
SINKS OF INSOLATION • 1. SENSIBLE HEAT FLUX. Energy used in changing the temperature of the air. • 2. GROUND HEAT FLUX. Energy used in changing the temperature of the planet’s surface (continents and oceans). • 3. LATENT HEAT FLUX. Energy used in changing the state of Water
WE NEED TO TRANSFER ENERGY • 1. SENSIBLE HEAT FLUX. Warm/cold air exchanges, global/seasonal wind patterns (ADVECTION)
WE NEED TO TRANSFER ENERGY • 1. SENSIBLE HEAT FLUX. Warm/cold air exchanges, global/seasonal wind patterns (ADVECTION) • 2. GROUND HEAT FLUX. Warm/cold surface water currents in oceans (2/3rd of global surface. (ADVECTION)
WE NEED TO TRANSFER ENERGY • 1. SENSIBLE HEAT FLUX. Warm/cold air exchanges, global/seasonal wind patterns (ADVECTION) • 2. GROUND HEAT FLUX. Warm/cold surface water currents in oceans (2/3rd of glabal surface. (ADVECTION) • 3. LATENT HEAT FLUX. Change of state of water - vapor, liquid, solid (Condensation/Evaporation; Freezing/Thawing) …. Precipitation (rain/snow)
TRANSFER OF LATENT HEAT Formation of rain and snow redistributes latent heat from point where evaporation took place (Input of latent heat of fusion and latent heat of vaporization). To the place where cloud formation and precipitation occurs (release of latent heat to the environment).
HOW TO EXTRACT LATENT HEAT FROM WATER VAPOR. • Cool the air!
HOW TO EXTRACT LATENT HEAT FROM WATER VAPOR. • Cool the air! • “Warm air can hold more moisture than cold air.”
HOW TO EXTRACT LATENT HEAT FROM WATER VAPOR. • Cool the air! • “Warm air can hold more moisture than cold air.” • Clausius-Clapeyron relationship
Decline in Temperature
Decline in Temperature (20°F) Decline in Moisture As Vapor (18 g.km-1)
Decline in Temperature (20°F) Decline in Moisture As Vapor (18 g.km-1)
ENGLAND! Decline in Temperature (20°F) Decline in Moisture As Vapor (10 g.km-1)
ENGLAND! Decline in Temperature (20°F) Decline in Moisture As Vapor (10 g.km-1)
TOO COLD TO SNOW? Decline in Temperature (20°F) Decline in Moisture As Vapor (1 g.km-1)
TOO COLD TO SNOW? Decline in Temperature (20°F) Saskatchewan Decline in Moisture As Vapor (1 g.km-1)
PUT ON THE FURNACE! 20 below!
Very, very low Moisture content
Warm to 70°F in the furnace
Can now hold more moisture
Moisture Deficit (19 g. km-1)
Moisture Deficit (19 g. km-1)
GLOBAL AIR CONDITIONERS??? Q. How to make air cooler?
GLOBAL AIR CONDITIONERS??? Q. How to make air cooler? Make it rise in the atmosphere and it will Cool at the lapse rate! (Equation of state of an ideal gas!) Lapse rate = ~6.4°C/km
WHERE IN THE WORLD IS THE AIR RISING (AND COOLING)? That is where we will get condensation clouds and precipitation.
WHERE IN THE WORLD IS THE AIR RISING (AND COOLING)? That is where we will get condensation clouds and precipitation. GLOBAL CIRCULATION PATTERNS – WHERE IS AIR RISING IN TROPOSPHERE?
1. Above the migrating equatorial Low pressure. Inter-tropical Convergence Zone HIGH 45-60°N LOW LOW HIGH HIGH HIGH 30°N Tropopause LOW LOW LOW 0° 30°S HIGH HIGH HIGH LOW LOW 45-60°S HIGH
June December
HIGH 45-60°N LOW LOW HIGH HIGH HIGH 30°N 2. Above the Low pressure zones at 45-60°. Planetary Front Tropopause LOW LOW LOW 0° 30°S HIGH HIGH HIGH LOW LOW 45-60°S HIGH
GLOBAL FURNACES??? Q. How to make air warmer?
GLOBAL FURNACES??? Q. How to make air warmer? Make it descend in the atmosphere and it will cool at the lapse rate! (Equation of state of an ideal gas!) Lapse rate = ~6.4°C/km
WHERE IN THE WORLD IS THE AIR DESCENDING (AND WARMING)? That is where we will get evaporation, clear skies and deserts.
WHERE IN THE WORLD IS THE AIR DESCENDING (AND WARMING)? That is where we will get condensation clouds and precipitation. GLOBAL CIRCULATION PATTERNS – WHERE IS AIR DESCENDING IN TROPOSPHERE?
HIGH 45-60°N LOW LOW HIGH HIGH HIGH 30°N 1. Above the High pressure zones at 30°. Sub-tropical anticyclones Tropopause LOW LOW LOW 0° 30°S HIGH HIGH HIGH LOW LOW 45-60°S HIGH
Fig. 2 The zonal height structure over ocean of observed climatological annual mean RH from AIRS (2002–2007) (color scale), with model mean projected changes in cloud amount from the CMIP3 model archive (contour lines, 0.5% intervals, dashed for cloud loss). J T Fasullo, K E Trenberth Science 2012;338:792-794 Published by AAAS
Fig. 3 (A) Median change in simulated top-of-atmosphere net shortwave flux as a function of latitude under 21st-century warming in CMIP3 SRES A1B projections.
SUB-TROPICAL HIGH PRESSURE Mojave