It would be easier to first define two terms: tidal friction and tidal heating. Tidal friction: Tides stretch the oceans, and to a small extent, the solid mass of a planet or satellite. In one complete rotation, the planet material keeps deforming and relaxing. This takes energy away from the rotation, transforming it into heat. Tidal heating: The heating of a planet's interiour as a result of tidal friction. How does this affect the atmosphere? Tidal heating enhances outgassing of volatiles that contribute or replenish a planet's atmosphere through volcanism. Tidal heating also can generate sub-surface liquid oceans on water-rich rocky planets that would otherwise be frozen. An example of this is one of Jupiter's moons, Io, which is in a gravitational struggle with Jupiter and its fellow moons. This creates tidal forces that constantly distort its interiour, resulting in frequent volcanic activity. Without the gravitational force and subsequently its turbulent tides, Io would be a frozen planet. It also drives plate tectonics. Since tides increase volcanic activity, it would be helpful to read up on how volcanoes affect the atmosphere as well. Sources: http://www.physics.mcgill.ca/~crawford/PSG/PSG11/204_97_L11.9_tidfric.html http://en.wikipedia.org/wiki/Tidal_heating http://www.redorbit.com/news/space/1587123/tides_affect_planet_habitability/ http://www.planetaryexploration.net/jupiter/io/tidal_heating.html Volcanic Effects: http://en.wikipedia.org/wiki/Volcano#Effects_of_volcanoes