Atmosphere of Earth (see the temperature section, below). Because the general pattern of the temperature/altitude profile is constant and measurable by means of instrumented balloon soundings, the temperature behavior provides a useful metric to distinguish atmospheric layers. In this way, Earth's atmosphere can be divided (called atmospheric stratification) into five main layers. Excluding the exosphere, the atmosphere has four primary layers, which are the troposphere, stratosphere, mesosphere, and thermosphere. From highest to lowest, the five main layers are: The exosphere is the outermost layer of Earth's atmosphere (i.e. the upper limit of the atmosphere). It extends from the exobase, which is located at
Where We Are Tour: Live from the O2 Where We Are Tour: Live from the O2 Where We Are Tour: Live from the O2 is a concert DVD by Irish boy band Westlife from their Where We Are Tour. During the group's Where We Are Tour, it was confirmed that their May 14 concert at the O2 Arena, London, England was recorded. The release date was then set as 29 November 2010 for both DVD and Blu-ray formats, making it the band's first release on Blu-ray. Pre-order links were set up by Play.com on 12 October 2010. The album includes an unseen backstage documentary during said tour and