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Lecture 5Atmospheric structure
TemperatureSolar and earth radiation
Stable?
Brick
Stable?
How can the atmosphere be made more stable? More unstable?
Cold
Warm
Warm
Cold
Stable Unstable
night day
Inversion layer
Inversion layerTemperature increases with height
Stable
Cold
Warm
Why does the smoke stay all the valley?
Cold
WarmInversion layer
The Stratosphere inversion layer, stable?
Q: Why does the temperature increase with height in the stratosphere?
contains ozone layer peak concentrations are at about 20-30 km
Ozone absorbs ultraviolet radiation (UV)
The ozone then reemits this energy in the form of heat into the stratosphere, warming it up in the mid-upper parts of the layer
97% of atmospheric ozone is in the stratosphere
Ozone maximum
The Mesosphere
Bounded by the stratopause from below and the mesopause from above
99.9 % of air is below this level
The Thermosphere The layer above the mesosphere
Temperature increases with height
What are weather
elements?
NYC daily Weather
Temperaturedew point temperature
Relative humidity
Wind
Rain
Weather Elements
“Climate is what you expect, weather is what you get.”
– Robert Heinlein
Climate is the long-term average
of weather
What is Climate?
Is Weather or Climate ?
Today’s Temperature in NYC?
Winter temperature?
Tornado?
Ice Age?
Annual variability of precipitation in NYC?
Climate
Weather
Weather
Climate
Climate
Climate change usually refers to temperature change
Temperature
Energy
is defined as the ability to do work
kinetic energy is the energy of motion
Kinetic Energy = 21
mass velocity2mv m v
kinetic energy is large when velocity is large
Temperature
21 1 1
1
2e m v
1
m = mass
v = velocity
2
energy
1
2kinetic
e mv22 2 2
1
2e m v
221
2i i ie m v
i
2 2 2 2 21 1 2 2 3 3
2
1 1 1 1 1... ...1 2 2 2 2 2
2 2
i i N NB
m v m v m v m v m vk Tmv
N
kB is the Boltzmann constant
is the average kinetic energy of its constitute atoms and molecules
Temperature and Heat
Heat energy exchange from one object to another
Absolute temperature is proportional to the average kinetic energy of its constitute atoms and molecules
What is difference between temperature and heat?
Object 1 Object 2
FasterSlower
Heat = an exchange of kinetic energy
Equilibrium = Both objects have the same temperature
Heat
Latent Heat
is energy exchange from one object to another
energy required for a substance (i. e. water) to change from one state to another at constant temperature
Sensible Heatheat added or taken from a gas, liquid or solid that
causes a change in temperature
Lecture 4- 20
Need energy
release energy
Need energy
release energy
Latent Heat energy required for water to change from one state to another at constant temperature
scale melting point of ice
boiling point of water
Fahrenheit (oF)
32 212
Celsius(oC)
0 100
Kelvin (K)
273 373
• Relative size of a degree F vs. a degree C--compare the number of degrees between freezing and boiling:
100oC = 180oF 1oC = 1.8oF
Temperature Scales:
Fahrenheit and Celsius
(oC x 1.8) + 32 = oF
(oF - 32) / 1.8 = oC
Why Kelvin temperature is also called absolute temperature?
Third Law of Thermodynamics
It is impossible to cool a body to absolute zero by any finite
process.
Although one can approach absolute zero as closely as one desires, one cannot actually reach this limit.
There are three ways of heat transfer in the atmosphereConduction
ConvectionRadiation
Heat Transfer
Heat Transfer
Conduction
from warm to cold from molecular motions
Air is a poor conductor of heat Basically insignificant
Lecture 4- 26
Convectiontransfer energy through mass movement of a substance
Q: what are examples of atmospheric convection?
consider a hot parcel of air near the ground
what is the parcel going to do?
It’s going to rise, why?
a thermal is formed
Q: By which mechanism is the heat transferred from ground to the air adjacent to the ground?
Thermals