Atmosphere of Earth surface. The refractive index of air depends on temperature, giving rise to refraction effects when the temperature gradient is large. An example of such effects is the mirage. "Atmospheric circulation" is the large-scale movement of air through the troposphere, and the means (with ocean circulation) by which heat is distributed around Earth. The large-scale structure of the atmospheric circulation varies from year to year, but the basic structure remains fairly constant because it is determined by Earth's rotation rate and the difference in solar radiation between the equator and poles. The first atmosphere consisted of gases in the solar nebula,
Harry Potter and the Deathly Hallows – Part 2 (video game) critics, though some critics found "Part 2" an improvement of "Part 1". Lowest ratings on Metacritic came from GamesRadar, stating, "This is the absolute nadir of the series. Harry Potter has finally devolved into a total cash-in and we can't score it low enough." GamingXP gave the Xbox 360 and PC versions positive reviews, saying "Where graphical aesthetics, thrilling atmosphere and a cinematic soundtrack celebrate their marriage, the gamer always wins." "The Escapist" gave it two-and-a-half stars out of five and said of the game, "The shooting mechanics and levels are getting better but the encounters themselves are too repetitive.