Climatology

Climate vs. Weather

The difference between weather and climate is a measure of time. Weather is what conditions of the atmosphere are over a short period of time, and climate is how the atmosphere "behaves" over relatively long periods of time.

Climate is usually over a 30 day period or longer.

What Controls Our Climate?

The Sun Atmospheric Gases (Greenhouse

Gases) Volcanic Eruptions Surface Albedo (reflectivity) snow

cover Ocean Currents Changes in earth’s orbit

(Milankovitch Cycles) Meteorite Impacts Living organisms (plants, animals,

microbes)

The Solar Cycle

Solar Max

Space Weather

Changes in the Solar Cycle

http://www.rockymountainstars.com/Pre_AP_Geo_Solar_Variation.htm

1645 to 1750 called the Maunder Minimum A period of little to no sunspot activity.

The Energy Budget

Changes in the Energy Budget

Small changes in any of these energy budget parameters will cause the earth to heat up or cool off.

Example: More ice would increase reflectivity or albedo creating a positive feedback which would lower the global temperature.

Volcanic Eruptions

In 1915 Mt. Tombora erupted in Indonesia. This was the largest eruption in 1,300 years.

The dust surrounded the globe which created a constant fog like haze which blocked out sunlight.

1916 was known as the year without a summer. A deep frost occurred over much of the US in June killing off most of the crops.

Mt. Pinatubo

Effect of Mt. Pinatubo

The eruption of Mt. Pinatubo in 1991 put enough aerosols into the stratosphere to lower the global temperature by 0.9 degrees Fahrenheit.

Ocean Currents

El Nino

El Nino Affect on the US

The Gulf Stream Warms Europe

The Milankovitch Cycles

Long term changes in the earth’s orbit (eccentricity) around the sun and axial tilt can change the overall heat balance of our planet.

A decrease in the axial tilt will cause less extreme seasons in the upper latitudes. These resulting cooler summers do not melt all the snow & ice from the previous winter which over time can lead to an ice age.

Changes in Eccentricity 100,000 cycle beat frequency

Axial Tilt Obliquity 41,000 year cycle

Axial Precession 26,000 year cycle

The 100,000 year cycle

There seems to be correlation with the 100,000 year cycle of the eccentricity in our orbit and ice ages.

100,000 year cycle & Ice Ages

Meteorite Impacts

The K-T Boundary 63 million Years

Banded Iron Formations BIF

The great oxygen event occurred 2.4 billion years ago.

Oxygen released from photosynthetic blue-green algae combined with iron in the sediment to create red & black bands of oxidized iron.

The banding may be caused by seasonal variations in photosynthesis and oxygen production by algae.

Banded Iron