an atmospheric transition zone or shell located between the mesosphere and the thermosphere at an altitude of c. 80 to 85 km (c. 50 to 53 miles) in which temperatures begin to rise with increasing altitude
"mesopause." YourDictionary, n.d. Web. 14 January 2019. <https://www.yourdictionary.com/mesopause>.
mesopause. (n.d.). Retrieved January 14th, 2019, from https://www.yourdictionary.com/mesopause
The boundary between the upper mesosphere and the lower thermosphere, approximately 80 km (50 mi) above the Earth's surface. It is the site of the coldest temperatures in the Earth's atmosphere, with temperatures of −100°C (−148°F).