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- The fundamental aim is to understand the circulations of the atmosphere
and ocean and the observed distributions of physical quantities such as
temperature.
- The temperature distribution can be viewed as the result of a
"competition" between the sun, which tries to warm the tropics
more than the poles (and so create horizontal contrasts), and gravity ,
which tries to remove horizontal contrasts and arrange for warmer fluid
to overlie colder fluid.
- This "competition“ is complicated by such effects as the rotation
of the earth, the variation of the angle between gravity and the
rotation axis (the beta effect), and contrasts between the properties of
air and water.
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- Weight = mass x gravity
- Density = mass / volume
- Pressure = force / area
- = weight / area
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- The atmosphere is not a perfect blackbody, it absorbs some wavelength of
radiation and is transparent to others (such as solar radiation). è Greenhouse effect.
- Objective that selectively absorbs radiation usually selectively emit
radiation at the same wavelength.
- For example, water vapor and CO2 are strong absorbers of infrared
radiation and poor absorbers of visible solar radiation.
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- The fundamental aim is to understand the circulations of the atmosphere
and ocean and the observed distributions of physical quantities such as
temperature.
- The temperature distribution can be viewed as the result of a
"competition" between the sun, which tries to warm the tropics
more than the poles (and so create horizontal contrasts), and gravity ,
which tries to remove horizontal contrasts and arrange for warmer fluid
to overlie colder fluid.
- This " competition“ is complicated by such effects as the rotation
of the earth, the variation of the angle between gravity and the
rotation axis (the beta effect), and contrasts between the properties of
air and water.
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- The potential temperature of an air parcel is defined as the the
temperature the parcel would have if it were moved adiabatically from
its existing pressure and temperature to a standard pressure P0
(generally taken as 1000mb).
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- Dry adiabatic lapse rate is
constant = 10ºC/km.
- Moist adiabatic lapse rate is NOT
a constant. It depends on the temperature of saturated air parcel.
- The higher the air temperature, the smaller the moist adiabatic lapse
rate.
- èWhen warm,
saturated air cools, it causes more condensation (and more latent heat
release) than for cold, saturated air.
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- The larger the solar zenith angle, the weaker the insolation, because
the same amount of sunlight has to be spread over a larger area.
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- Polarward heat flux is needed to transport radiation energy from the
tropics to higher latitudes.
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- Vertical temperature gradients
- Convection occurs that tries to reduce the vertical gradients
- Vertical variation of air density (i.e., stratification)
- Horizontal temperature gradients
- èFluid motion
takes place to reduce the gradients
- èThe motion
(i.e., the adjustment) takes place in a rotating and stratified system.
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