Atmosphere of Earth

Heating the Atmosphere A. What Happens to Incoming Solar Radiation? When radiation strikes an object, 3 things happen: some of the energy is absorbed by the object (converted to heat+temperature rises), some substances (water+air) are transparent to certain radiation wavelengths + transmit energy, and some radiation is bounced off the object without absorption/transmission. Reflection + scattering are responsible for redirected solar radiation. Out of the total solar radiation from the sun, 50% is absorbed by the land/sea, 20% is absorbed by the atmosphere/clouds, 5% is reflected from the land/sea surface, 5% is backscattered to space by the atmosphere, 20% is reflected by the clouds (in total, 30% is lost to space by reflection/scattering). B. Reflection and Scattering

Vertical Structure of the Atmosphere A. Pressure Changes Atmospheric Pressure: weight of the air above - at sea level, the avg. pressure ~ 1000 millibars (mb), or ~ 1 kg/cm2 Pressure at higher altitudes is less ? of the atmosphere is below 5.6 km (3.5 mi); at 16 km (10 mi), 90% of the atmosphere has been passed, and > 100 km (62 mi), only 0.00003 % of all gases in the atmosphere remain. Rest of atmosphere merges with space vacuum. B. Temperature Changes Near Earth?s surface, air temperature drops with an increase of height. I. Troposphere (air ?turns over?) Lowermost atmosphere layer (we live in here); temperature decreases with an altitude increase. All important weather occurs here.