¥Thermosphere: highest layer, (also
called ionosphere), merges with space gradually, temp. increases with altitude heated by
cosmic rays
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¥Mesophere: below
thermosphere, extends to altitude of ~80 km (50 mi), grows
cooler with increasing altitude
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¥Stratosphere: below mesosphere, contains protective Òozone
layerÓ absorbs much of SunÕs harmful uv radiation,
extends to ~50 km (31 mi), hotter with increasing altitude,
small amounts of ozone vital for photosynthesis, BUT intense uv
damages living tissue
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¥Troposphere: atmospheric
layer closest to Earth surface, this is where weather
happens, becomes colder with increasing elevation, 8 km (5 mi) in
Polar regions, up to 17 km (10.5 above equator, layer where greenhouse
gases are trapped and where global warming occurs.
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