Kelley observed that high frequency radar was returned strongly at high latitudes, which are known as its namesake "summer echoes."  Red flashes of light with tendrils hanging below, known as sprites, are observed in this layer during thunderstorms. An unusual type of cloud which glows bluish-white and is usually seen from near the poles is found in this layer, and is known as a noctilucent cloud. Zonal flow is very small near the top of this layer of the atmosphere, which has temperature decreasing with increasing heig
Kelley observed that high frequency radar was returned strongly at high latitudes, which are known as its namesake "summer echoes."  Red flashes of light with tendrils hanging below, known as sprites, are observed in this layer during thunderstorms. An unusual type of cloud which glows bluish-white and is usually seen from near the poles is found in this layer, and is known as a noctilucent cloud. Zonal flow is very small near the top of this layer of the atmosphere, which has temperature decreasing with increasing height. For 10 points, name this region of the atmosphere from about 50 to 85 kilometers above the surface, whose upper section is the coldest part of the atmosphere, which is also the location where meteors usually burn up.
Kelley observed that high frequency radar was returned strongly at high latitudes, which are known as its namesake "summer echoes."  
mesosphere