WK1 Day 2 Notes: Abiotic Environments

01/14/2026 Notes: Abiotic Environments

Solar radiation:

Fate of solar radiation…

reflected by atmosphere

absorbed by atmosphere

reflected by earth”s surface

Solar radiation:

Earth’s atmosphere absorbs what percentage of solar radiation?

50% is absorbed by Earth’s surface

Solar radiation:

What is ALBEDO?

fraction of incident radiation that is reflected by a surface or body

Climate:
Humidity is…

Water content in the air defined in terms of vapor pressure\

units are megapascal (Mpa)

Climate:

Vapor Pressure (VP)

Amount of pressure water vapor exerts without dry air

Climate:

Saturation VP

Pressure that water vapor exerts when air is saturated with moisture (basically can’t hold water anymore

Climate:

Vapor Pressure Deficit

Sat VP - Current VP

Climate:

Dew Point Temperature

Temperature at which saturation VP is achieved for a given water content of the air

Climate:
El Niño

• Happens every 4-7 years

• Disruption of the normal ocean-atmosphere system in the tropical Pacific Ocean

• aka warm event

• aka ENSO

Climate:
The Walker Circulation is…

• Convection of air

• Normal ocean-atmosphere system

• Consistent air pressure difference

• Wind blows from east to west, as a result the cooler water (nutrient rich) from the bottom of the ocean rises up and the warmer water pushes down.

Climate:

How does El Nino occur?

• No significant difference in hair pressure

• Warmer surface water doesn’t get blown from east to west, cooler water doesn’t rise making the water warmer than usual.

Climate:

Southern Oscillation

A seesaw of air pressures on the eastern and western halves of the Pacific.

Climate:

Possible cause of ENSO ( El Nino and Southern Oscillation)

• Underwater earthquakes on ocean floor

• Pacific ocean tries to respond on annual time scale with the sun but due to be being too wide it cause anomalies like ENSO.

Climate:

Consequences of El Nino

• Destructive flooding, Increase rainfall across the southern tier of the uS and in Peru

• Vegetation growth in Galapagos archipelago

• Drought in West Pacific and fire in Australia

• The suppression of nutrient rich cold water rising in the eastern Pacific causes a decline in fishery and bird populations on coast of Americas.

• Decline in Weddell seal population in Antarctica

• Reduce in corn harvest East Africa (caused by excessive dryness and moisture)

Climate:

What is La Nina?

• Period when ocean temperatures across the central and eastern tropical Pacific Ocean are cooler than normal.

• Occurs after some El Nino years

• aka cold event/episode

Climate:

Consequences of La Nina…

• Warm winters in Southeastern US, colder than normal winters from the Great Lakes to the Pacific Northwest

• 1988 La Nina ties to the Bangladesh Floods and droughts in the Midwest United States.