HEAT ENERGY TRANSFERAND AIR TEMPERATURE

As we have seen, Earth’s Weather and Climate are the results of the intricate interrelationships between the Earth and the Sun, and between the components of our Atmosphere and Geosphere:

And we considered the definitions of

Weather and Climate

Weather: refers to the condition of atmospheric elements at a given time, and for a specific area.

Climate: average of weather conditionsfor 30+ years (including atmospheric anomalies).

We also asked the obvious question: How does Insolation relate to Heat Energy Transfer and to Weather and Climatephenomena on Earth?

Now, Let’s Recall the5+ Basic Elements of the Atmosphere– the main ingredients of weather and climate-- Also called Elements of Weather and Climate

In this segment, we’ll discuss the first two elements:

• Solar Energy-- Insolation and Heat Energy Transfer

• Temperature

• Pressure• Wind• Precipitation+ Air Masses (and Fronts)

Heat and Temperature Heat vs. Temperature: Heat is the total kinetic energy of all the atoms that make up a substance, while Temperature is the average kinetic energy of the individual molecules of a substance. Heat is measured in Calories per gramTemperature in Fahrenheit , Celsius or Kelvin scales.

Heating the Atmosphere:Creation of atmospheric warmth depends on: the 47% of insolation reaching Earth’s surface

(on both land and water); and the transfer of heat energy from Earth back to

the Atmosphere.

Processes of Heat Energy Transfer

This is accomplished through a number of Physical Processes:

Radiation: electromagnetic energy transferred from the sun (shortwave solar radiation), and through Earth radiation (long-wave infrared radiation).

Conduction: Heat flows from hotter to colder body to equalize temperature, as along the interface of atmosphere and Earth’s surface

[But this process is less significant because air is not a good conductor of heat]

Convection: vertical transfer of heat through the atmosphere and ocean, in the form of convection currents

Advection: horizontal heat transfer, e.g., from Equator to Polar regions, through wind and ocean currents

Latent Heat of Condensation: Latent Heat of Evaporation → Water Vapor (traps Heat) ↓Latent Heat of Condensation → Water droplets (releases heat)plays a major role in energy transfer within the Earth System; the power of all severe weather is supplied by this process.

6 Controls of Temperature Often called Factors of Weather and Climate

• Latitude

• Land and Water Distribution

• Ocean Currents

• Altitude

• Landform Barriers

• (Cloud Cover) • Human Activity – Destruction of forests,

creation of reservoirs, urbanization (“Urban Heat Islands”)

Broad Oceanic Circulation Patterns

1. Short-term Variations in Temperature, due to:Annual and Diurnal variations in Insolation

Cloud Cover – about 50% average cloud cover – cooler days, warmer nights

Differential Heating of Land and Water – Maritime vs. Continental locations

Reflection – albedo – high in snow and ice,low in forest cover

Horizontal Air Movement

Variations in Temperature

2. Vertical Distribution of Temperature,reflected in:

Normal Lapse Rate (3.6oF/1000 ft)

Temperature Inversions, e.g., in coastal areas, as in L.A.

Surface Inversions – in the hilly areas – Fog and Frost

3. Global Temperature Distributionmanifested through:

Isotherm Maps Temperature Gradient

Annual March of TemperaturesClimographs

Annual March of Temperatures(Climographs)