HEAT ENERGY TRANSFER
AND 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:
We also asked the obvious question:
How does Insolation relate to Heat Energy
Transfer and to Weather and Climate
phenomena on Earth?
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 conditions
for 30+ years (including atmospheric
anomalies).
Now, Let’s Recall the
5+ 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)
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.
Heat and Temperature
Heat is the total kinetic energy of all the atoms
that make up a substance; it is a form of energy
that flows from one system or object to another
due to temperature difference.
Temperature is the average kinetic energy of
the individual molecules of a substance.
Heat is measured in Calories per gram
Temperature in Fahrenheit , Celsius or Kelvin scales.
Heat and temperature are related because changes in
temperature are caused by the absorption or emission of
heat energy.
Processes of Heat Energy Transfer
Basically, absorption or emission of heat energy –
 creates and maintains atmospheric warmth
 fosters a redistribution and balancing of global temperatures
And these desired results are 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: Heat released or absorbed during a phase
Change; “Latent” since heat is not felt
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
•
Altitude/Elevation
•
Cloud Cover
•
Land and Water Distribution
•
Ocean Currents
•
•
Landform Barriers
Human Activity – Destruction of forests,
creation of reservoirs, urbanization
(“Urban Heat Islands”)
1.
Latitude
Which zones have the
greatest and least
annual variation in
insolation? Why?

World distribution of insolation
2.
Altitude/Elevation
3.
Cloud Cover
Why do desert regions have large diurnal
temperature variations?
4.
Land and Water Distribution
Marine and Continental Effects ?
San Francisco
and
Wichita
San Diego and Dallas
5.
Ocean Currents
Broad Oceanic Circulation Patterns - Gyres
Variations in Temperature
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
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 hilly areas – Fog and Frost
3. Global Temperature Distribution
manifested through:
Isotherm Maps
Temperature Gradient
and
Annual March of
Temperatures
Climographs
Average January
Temperature
Average July
Temperature
Annual March of Temperatures
(Climographs)
Annual Temperature Range