Circulation in the Atmosphere
This presentation is the property of its rightful owner.
Sponsored Links
1 / 27

Circulation in the atmosphere PowerPoint PPT Presentation


  • 83 Views
  • Uploaded on
  • Presentation posted in: General

Circulation in the Atmosphere. Circulation in the atmosphere. Balance of forces in the fluid motion. Forces due to planetary rotation Centrifugal force  Geoid Coriolis force  Deflection of moving fluid Pressure gradient force From high to low pressure.

Download Presentation

Circulation in the atmosphere

An Image/Link below is provided (as is) to download presentation

Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.


- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -

Presentation Transcript


Circulation in the atmosphere

Circulation in the Atmosphere

Circulation in

the atmosphere


Balance of forces in the fluid motion

Balance of forces in the fluid motion

  • Forces due to planetary rotation

    • Centrifugal force  Geoid

    • Coriolis force  Deflection of moving fluid

  • Pressure gradient force

    • From high to low pressure


Circulation in the atmosphere

Deflection of air flow due to Coriolis force

Low Pressure

_

Surfaces of

constant pressure

y (latitude)

x (longitude)

+

High Pressure


Circulation in the atmosphere

Balanced flow: geostrophic balance

Fpressure

Low Pressure

High Pressure

FCoriolis

  • Coriolis force 90 degrees to the right

  • Pressure force down the gradient

  • Air flows along the line of constant pressure

  • Particles will have the high pressure on their right (opposite in the southern hemisphere)


Circulation in the atmosphere

Geostrophic circulation

  • What would be the direction of (1) the pressure force and (2) the Coriolis force in geostrophic balance?

  • What would be the direction of geostrophic flow?

L

H

Cyclonic

Anti-cyclonic


Circulation in the atmosphere

Geostrophic circulation

Now we are in the Southern Hemisphere, what would be the direction of the geostrophic flow?

L

H

Cyclonic

Anti-cyclonic


Circulation in the atmosphere

Tropical cyclone: an intense low pressure system

H

H

L

H

H

Air circulates around the low pressure


Circulation in the atmosphere

Flow under radial pressure gradient

  • A bucket full of water

  • Open up a hole in the middle

    • Generates a low pressure

  • What would happen to the water?

    • Non-rotating

    • Rotating


Circulation in the atmosphere

Tropical cyclones

  • Coriolis effect

  • Air flows around the low pressure

  • counter-clockwise

Energy source

Warm, moist air from tropical ocean


Circulation in the atmosphere

Storm surge

Graphic illustration by National Hurricane Center

http://www.nhc.noaa.gov/surge/animations/hurricane_stormsurge.swf


Circulation in the atmosphere

Atmosphere-ocean interaction

What are the ways that the Earth’s atmosphere and ocean interact?


Circulation in the atmosphere

Wind-driven ocean currents

  • Atmospheric winds applies frictional force on the surface waters

  •  Ocean waves

  • Wind-driven circulation

    • (next week)


Circulation in the atmosphere

Water cycle

Implications to the salinity of seawater?


Circulation in the atmosphere

Temperature

ITCZ

Warm SST, low SSS

Excess precipitation

Salinity

Subtropics

Warm SST, high SSS

Excess evaporation

Sea surface temperature and salinity are controlled by air-sea interaction


4 components of air sea heat flux

4 components of air-sea heat flux

  • Incoming shortwave radiation

    • Latitudes, cloud cover

  • Outgoing longwave radiation

    • Temperature, water vapor, cloud cover

  • Sensible heat flux

    • Boundary layer turbulence

  • Latent heat flux

    • Evaporation


Shortwave radiation

Shortwave radiation

  • Climatology

    • Average over long time period (1968-1996)

    • Upward positive (positive into the atmosphere)


Factors controlling sw radiation

Factors controlling SW radiation

  • Latitude

  • Cloudines (albedo)


Longwave radiation

Longwave radiation

  • Climatology (1968-1996)

    • Upward positive (positive into the atmosphere)


Longwave radiation1

Longwave radiation

  • SST, cloud and water vapor


Sensible heat flux

Sensible heat flux

  • Climatology (1968-1996)

    • Upward positive (positive into the atmosphere)

    • Turbulent heat exchange between ocean and atmosphere


Sensible heat flux1

  • Driven by surface wind speed and air-sea temperature difference

Sensible heat flux


Latent heat flux

Latent heat flux

  • Climatology (1968-1996)

    • Upward positive (positive into the atmosphere)

    • Proportional to the rate of evaporation


Latent heat flux1

  • Rate of evaporation

    • - Wind speed and relative humidity

Latent heat flux


Net heat flux

Net heat flux

  • Climatology (1968-1996)

    • Upward positive (positive into the atmosphere)


Circulation in the atmosphere

Ocean heat transport

  • Ocean gains heat from the atmosphere in tropics

  • Ocean circulation transports heat poleward, and release back to the atmosphere at high latitudes


Circulation in the atmosphere

Biogeochemical cycle

(in October after midterm)


  • Login