Chapter 4 Global Climate and Biomes

Earth Regions near the equator (0 o ) receive light at 90 o High latitudes receive light at low angles 1.Sun rays travel shorter distance to equator (energy is lost the farther it travels) 2.Sun rays distributed over smaller area (more concentrated) 3.Albedo Unequal Heating of the Earth

Solar energy is concentrated near the equator Image: Netherlands Center for Climate Research

Energy Latitude absorbed solar energy

Energy Latitude absorbed solar energy Emitted IR energy

Energy Latitude absorbed solar energy Emitted IR energy More energy is absorbed near the equator than emitted And more energy is emitted near the poles than is absorbed.

Energy Latitude net radiation surplus

Energy Latitude net radiation surplus net radiation deficit Excess energy at the equator is transferred towards the poles by convection cells

Solar energy received is greatest near the equator. Energy is moved from the equator to the poles.

Solar energy received is greatest near the equator. Energy is moved from the equator to the poles. Energy is transferred by wind and ocean currents Solar Energy

Air near the equator is warmed, and rises solar radiation Hadley Circulation Cell

The rising air creates a circulation cell, called a Hadley Cell solar radiation L H H Rising air  low pressure Sinking air  high pressure Hadley Circulation Cell H

Warm air rises Rising air is replaced Hadley Circulation Cell

Warm air rises Air cools, sinks Rising air is replaced Hadley Circulation Cell

Warm air rises Air cools, sinks Rising air is replaced LOW HIGH Hadley Circulation Cell

Warm air rises Air cools, sinks Rising air is replaced LOW HIGH Rising air cools; the air’s capacity to hold water drops. Rain! No rain in regions where air is descending

The Coriolis Effect Rotation of the Earth leads to the Coriolis Effect This causes winds (and all moving objects) to be deflected: –to the right in the Northern Hemisphere –to the left in the Southern Hemisphere What makes Venus different?

The Coriolis Effect Based on conservation of angular momentum We experience linear momentum when we are in a car that is traveling fast and then stops suddenly.

Planet Earth rotates once per day. Objects near the poles travel slower than those near the equator.

Objects near the poles have less angular momentum than those near the equator. When objects move poleward, their angular momentum causes them to go faster than the surrounding air. Conversely, they slow as they move towards the equator.

When objects move north or south, their angular momentum causes them to appear to go slower or faster. This is why traveling objects (or air parcels) deflect to the right in the northern hemisphere and to the left in the southern hemisphere.