Chapter 23 The Atmosphere Section 2 Solar Energy Notes 23-5

Absorption and Infrared Warmth from the sun is infrared rays Objects on the surface heat up when the absorb infrared energy and visible light The rays given off by objects are longer than the ones given off by the sun The shorter wavelength infrared waves will go through the atmosphere The longer wavelength infrared waves will be absorbed by CO2 and H2O in the atmosphere

Greenhouse Effect The absorption of long wavelength infrared by the atmosphere traps heat near the surface The long waves are trapped and prevented from escaping This heats up the lower atmosphere

Greenhouse Effect Carbon dioxide has been added to the atmosphere by burning of fossil fuels It absorbs infrared radiation Because the amount of CO2 in the atmosphere has increased and will continue to increase, global warming will continue and possibly become worse

Variations in Temp. Sun doesn’t heat the earth equally in all places Temperatures are higher at the equator than at the poles Equator has direct rays from the sun to heat the surface At the Poles, the rays are slanted They spread their energy over a larger distance

Variations in Temp. Elevation warm during the day and cool down at night They don’t have water vapor and CO2 to trap the heat in at those high elevations Deserts are the same They don’t have enough water vapor to hold the temperature up at night

Variations in Temp. Water temperatures change less than land temperatures Areas near bodies of water have more moderate temperatures Cooler during the day and warmer at night Winds can cool when from the water and warm when from the land

Variations in Temp. Delay in heating Sun is highest in the sky on June 21 not warmest until July Sun is highest in the sky at 12:00 noon Not warmest until around 2:00 or 3:00 in the afternoon

Conduction vs Convection Warm molecules move faster and transfer the heat by movement to other molecules Solids make good conductors Air is a poor conductor Convection: Warm air rises Makes a low pressure Cool air sinks Makes a high pressure Air moves from high to low pressure and creates winds