from the underlying surface. Processes responsible for the heat transfer
are:Convective flux
Eddy flux
L.w. radiation
L.w. radiation
Evaporation
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Heat fluxes in the atmosphere
Содержание
- 1. Heat fluxes in the atmosphere
- 2. Climate_Change_Attribution.
- 3. Heat flux notionThe quantity being transferred by the
- 4. Convective and advective heat fluxesAny air particle
- 5. Eddy heat fluxEddy heat flux is caused
- 6. The strongest fluxThe weakest fluxAlong with vertical eddy flux there are horizontal fluxes.At the same level
- 7. Eddy heat exchange differs from that of
- 8. Individual and local (partial) derivativesWhen an air
- 9. Energy equationTemperature variation is of prime interest
- 10. The same reasoning can be applied for
- 11. All members of this formula have the
- 12. After substituting into the basic equation and
- 13. Air temperature variation due to advectionAir temperature
- 14. 1. Non-periodical T variationsAbove boundary layer (in
- 15. 2. Periodical T variationsWithin the boundary layer
- 16. 3. Air mass moving over non-homogeneous surfaceAdvection
- 17. 4. Annual T variationMost important role toLocal,
- 18. Скачать презентанцию
Climate_Change_Attribution.
Слайды и текст этой презентации
Слайд 1Heat fluxes in the atmosphere
Heat to the atmosphere comes mainly
Слайд 3Heat flux notion
The quantity being transferred by the air parcels in
a unit of time through a unit of area facing
the transfer direction is called HEAT FLUX.There are convective heat flux and eddy heat flux.
Convective heat flux, in turn, is divided into advective one (horizontal heat transfer) and real convective (vertical heat transfer).
In meteorology, the horizontal heat flux is called advective flux (Qa), and the vertical one is called convective flux (Qc).
Слайд 4Convective and advective heat fluxes
Any air particle contains some amount
of heat. When moving, it carries this heat along. By
this way the heat is distributed in the atmosphere. However, that is not the only way for the heat distribution. Not less effective way is EDDY MIXING (EXCHANGE)Incoming heat flux is positive, outgoing flux is negative.
Слайд 5Eddy heat flux
Eddy heat flux is caused by wind velocity
pulsation
General conditions for eddy exchange
Permanency
Conservation
Passivity
Quantity does not satisfy
this conditions. Air temperature changes as the air ascending or descending. However, potential temperature satisfy.
Слайд 6
The strongest flux
The weakest flux
Along with vertical eddy flux there
are horizontal fluxes.
At the same level
Слайд 7Eddy heat exchange differs from that of other substances. Coefficients
A and K (for eddy heat exchange) are called coefficient
of eddy heat conductivity and temperature conductivity respectively.As the stratification is stable ( ) eddy heat flux directed downward
As the stratification is unstable ( ) eddy heat flux directed upward
Heat influx (outflow) notion
Heat influx = incoming heat flux – outgoing heat flux
Heat outflow
Heat influx
Слайд 8
Individual and local (partial) derivatives
When an air parcel moves, its
state parameters are not necessarily constant; they are function of
coordinates and time.For the moving parcel, the coordinates, in turn, are functions of time.
Individual derivative
Local derivative
Convective derivative
Advective derivative
Слайд 9Energy equation
Temperature variation is of prime interest for meteorologists. It
depends on heat influx. It can be determined on the
base of the energy conservation equation.Heat influx:
Heat influx unit
Mass of the volume is
Слайд 10The same reasoning can be applied for horizontal heat fluxes
Eddy
heat influx
Since the horizontal exchange is much smaller the vertical
one, for practical purposes this formula can be simplified
Слайд 11
All members of this formula have the same order of
magnitude
Substituting
and
into energy equation, we obtain
See the next slide
Слайд 12After substituting into the basic equation
and solution with respect
to , we obtain
This quantity is
small and can be neglected
Слайд 13Air temperature variation due to advection
Air temperature variation due to
vertical motion
Air temperature variation due to eddy mixing
Air temperature variation
due to radiation and water phase transfer
Слайд 141. Non-periodical T variations
Above boundary layer (in the free atm.)
Small
time intervals (about 24 h)
? no heat influx ? adiab.
processEnergy equation:
Слайд 152. Periodical T variations
Within the boundary layer (diurnal T variations)
long
time intervals
? only vertical eddy heat influx
Energy equation (
or equation of the conductivity of the atm.):
Слайд 163. Air mass moving over non-homogeneous surface
Advection and eddy exchange
are important
Taking steady state process
The process is called
air
mass transformationEnergy equation
Слайд 174. Annual T variation
Most important role to
Local, advective and convective
derivatives ? 0 over a long period of time
Energy equation
