Long‐Term Density Trend in the Mesosphere and Lower Thermosphere From Occultations of the Crab Nebula With X‐Ray Astronomy Satellites

Abstract

Understanding the changes of the middle and upper atmosphere is important to our life, as was illustrated by the discovery of the stratospheric ozone depletion. The importance is increasing, as we utilize the space environment for many purposes such as telecommunications, navigation, space tourism, and scientific projects to explore the universe. There are several known drivers of middle and upper atmosphere climate change, including the increase