How Does Weather Work?
Weather as a Feedback Loop
Unequal distribution of radiation due to earth axis tilt
is the ultimate driver of the weather.
Heat, energy flow is generally from the equatorial regions
to the polar regions.
Rotation of the earth sets up large scale circulation cells
called Hadley Cells As well
as Rossby Waves To learn more
about this go here
Ocean currents and temperature influence the temperature of the
air and hence its capacity to hold moisture
Large Scale climate is set up by the constant exchange of moisture
and energy between the ocean and the circulating atmosphere. These
determines large scale pattern of High and
Low pressure areas
Pacific Coast Pacific Maritime Climate
Cold Current, strong ON shore flow of dry air in the Summer no
East Coast Warm current, lots of moisture,
Bermuda High brings it a shore -summers suck!
- Let's see the Movie which shows
the seasonal evolution of these currents
Effects of Ice Ages
- Periodic Ice Ages ---> Glacial-Interglacial Periods
We currently are nearing the end of a small, minor interglacial period
- Major Period: ---> 100,000 years; 9 degree F decrease
- Minor Period: ---> 12,000 years; 5 degree F decrease
- Smaller Periods??: ---> 1,000 years; 3 degree F decrease
Major Ice Ages: Most of the Planet is Covered
Minor Ice Ages: 40 Latitude and Above
Little Ice Age: (1000-1850 AD; Irish Potato Famine; Nisqually Glacier)
Causes of Ice Ages -->
needs to be PERIODIC!
Changes sea level by 100 meters exposes continental shelfs
changes continental shelf composition due to increased deposition
changes hydrological cycle through less evaporation
changes landscape Great Lakes; Seattle; Stoss and Lee
Changes drainage patterns
changes topsoil characteristics
massive flooding episodes --> Eastern Washington
Solar Cycle --> no evidence
Volcanic Dust in Atmosphere --> why periodic?
CO Cycle --> why periodic? --> factor 2 reduction
causes 7 F drop
Increased precipitation at poles due to changing orientation of continental
Changes in mean temperatures of ocean currents --> what mechanism?
The most Probable Cause:
The Electronic Universe Project
Orbital Variations of the Earth!
- Eccentricity variation 90,000 years 5 variation
around mean value. This is due to Jupiter.
- Change of tilt of axis 24,000 years