circulation in the atmosphere
DESCRIPTION
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. - PowerPoint PPT PresentationTRANSCRIPT
![Page 1: Circulation in the atmosphere](https://reader036.vdocuments.net/reader036/viewer/2022081504/56813af5550346895da3760b/html5/thumbnails/1.jpg)
Circulation in the atmosphere
Circulation in the Atmosphere
![Page 2: Circulation in the atmosphere](https://reader036.vdocuments.net/reader036/viewer/2022081504/56813af5550346895da3760b/html5/thumbnails/2.jpg)
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
![Page 3: Circulation in the atmosphere](https://reader036.vdocuments.net/reader036/viewer/2022081504/56813af5550346895da3760b/html5/thumbnails/3.jpg)
x (longitude)
y (latitude)
+
_
Surfaces ofconstant pressure
Deflection of air flow due to Coriolis force
p
y
High Pressure
Low Pressure
![Page 4: Circulation in the atmosphere](https://reader036.vdocuments.net/reader036/viewer/2022081504/56813af5550346895da3760b/html5/thumbnails/4.jpg)
Fpressure
FCoriolis
1) Coriolis force 90 degrees to the right2) Pressure force down the gradient3) Air flows along the line of constant pressure4) Particles will have the high pressure on their right
(opposite in the southern hemisphere)
Balanced flow: geostrophic balance
High Pressure
Low Pressure
![Page 5: Circulation in the atmosphere](https://reader036.vdocuments.net/reader036/viewer/2022081504/56813af5550346895da3760b/html5/thumbnails/5.jpg)
H
L
• 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?
Geostrophic circulation
Cyclonic Anti-cyclonic
![Page 6: Circulation in the atmosphere](https://reader036.vdocuments.net/reader036/viewer/2022081504/56813af5550346895da3760b/html5/thumbnails/6.jpg)
Geostrophic circulation
H
L
Now we are in the Southern Hemisphere, what would be the direction of the geostrophic flow?
Cyclonic Anti-cyclonic
![Page 7: Circulation in the atmosphere](https://reader036.vdocuments.net/reader036/viewer/2022081504/56813af5550346895da3760b/html5/thumbnails/7.jpg)
Tropical cyclone: an intense low pressure system
L
H H
H
H
Air circulates around the low pressure
![Page 8: Circulation in the atmosphere](https://reader036.vdocuments.net/reader036/viewer/2022081504/56813af5550346895da3760b/html5/thumbnails/8.jpg)
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
![Page 9: Circulation in the atmosphere](https://reader036.vdocuments.net/reader036/viewer/2022081504/56813af5550346895da3760b/html5/thumbnails/9.jpg)
Tropical cyclones
Energy sourceWarm, moist air from tropical ocean
Coriolis effectAir flows around the low pressurecounter-clockwise
![Page 10: Circulation in the atmosphere](https://reader036.vdocuments.net/reader036/viewer/2022081504/56813af5550346895da3760b/html5/thumbnails/10.jpg)
![Page 11: Circulation in the atmosphere](https://reader036.vdocuments.net/reader036/viewer/2022081504/56813af5550346895da3760b/html5/thumbnails/11.jpg)
http://www.nhc.noaa.gov/surge/animations/hurricane_stormsurge.swf
Storm surge
Graphic illustration by National Hurricane Center
![Page 12: Circulation in the atmosphere](https://reader036.vdocuments.net/reader036/viewer/2022081504/56813af5550346895da3760b/html5/thumbnails/12.jpg)
Atmosphere-ocean interaction
What are the ways that the Earth’s atmosphere and ocean interact?
![Page 13: Circulation in the atmosphere](https://reader036.vdocuments.net/reader036/viewer/2022081504/56813af5550346895da3760b/html5/thumbnails/13.jpg)
Wind-driven ocean currents
Atmospheric winds applies frictional force on the surface waters
Ocean waves
Wind-driven circulation(next week)
![Page 14: Circulation in the atmosphere](https://reader036.vdocuments.net/reader036/viewer/2022081504/56813af5550346895da3760b/html5/thumbnails/14.jpg)
Water cycle
Implications to the salinity of seawater?
![Page 15: Circulation in the atmosphere](https://reader036.vdocuments.net/reader036/viewer/2022081504/56813af5550346895da3760b/html5/thumbnails/15.jpg)
Temperature
Salinity
Sea surface temperature and salinity are controlled by air-sea interaction
ITCZ Warm SST, low SSS Excess precipitation
SubtropicsWarm SST, high SSSExcess evaporation
![Page 16: Circulation in the atmosphere](https://reader036.vdocuments.net/reader036/viewer/2022081504/56813af5550346895da3760b/html5/thumbnails/16.jpg)
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
![Page 17: Circulation in the atmosphere](https://reader036.vdocuments.net/reader036/viewer/2022081504/56813af5550346895da3760b/html5/thumbnails/17.jpg)
Shortwave radiation• Climatology
• Average over long time period (1968-1996)
– Upward positive (positive into the atmosphere)
![Page 18: Circulation in the atmosphere](https://reader036.vdocuments.net/reader036/viewer/2022081504/56813af5550346895da3760b/html5/thumbnails/18.jpg)
Factors controlling SW radiation• Latitude• Cloudines (albedo)
![Page 19: Circulation in the atmosphere](https://reader036.vdocuments.net/reader036/viewer/2022081504/56813af5550346895da3760b/html5/thumbnails/19.jpg)
Longwave radiation• Climatology (1968-1996)
– Upward positive (positive into the atmosphere)
![Page 20: Circulation in the atmosphere](https://reader036.vdocuments.net/reader036/viewer/2022081504/56813af5550346895da3760b/html5/thumbnails/20.jpg)
Longwave radiation• SST, cloud and water vapor
![Page 21: Circulation in the atmosphere](https://reader036.vdocuments.net/reader036/viewer/2022081504/56813af5550346895da3760b/html5/thumbnails/21.jpg)
Sensible heat flux• Climatology (1968-1996)
– Upward positive (positive into the atmosphere)
– Turbulent heat exchange between ocean and atmosphere
![Page 22: Circulation in the atmosphere](https://reader036.vdocuments.net/reader036/viewer/2022081504/56813af5550346895da3760b/html5/thumbnails/22.jpg)
Sensible heat flux• Driven by surface wind speed and air-sea temperature difference
![Page 23: Circulation in the atmosphere](https://reader036.vdocuments.net/reader036/viewer/2022081504/56813af5550346895da3760b/html5/thumbnails/23.jpg)
Latent heat flux• Climatology (1968-1996)
– Upward positive (positive into the atmosphere)
– Proportional to the rate of evaporation
![Page 24: Circulation in the atmosphere](https://reader036.vdocuments.net/reader036/viewer/2022081504/56813af5550346895da3760b/html5/thumbnails/24.jpg)
Latent heat flux• Rate of evaporation
- Wind speed and relative humidity
![Page 25: Circulation in the atmosphere](https://reader036.vdocuments.net/reader036/viewer/2022081504/56813af5550346895da3760b/html5/thumbnails/25.jpg)
Net heat flux• Climatology (1968-1996)
– Upward positive (positive into the atmosphere)
![Page 26: Circulation in the atmosphere](https://reader036.vdocuments.net/reader036/viewer/2022081504/56813af5550346895da3760b/html5/thumbnails/26.jpg)
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
![Page 27: Circulation in the atmosphere](https://reader036.vdocuments.net/reader036/viewer/2022081504/56813af5550346895da3760b/html5/thumbnails/27.jpg)
Biogeochemical cycle(in October after midterm)