Nitric Oxide (NO) has been observed by the Solar Occultation For Ice Experiment (SOFIE) instrument onboard the Aeronomy of Ice in the Mesosphere (AIM) satellite for 9 continuous years throughout the thermosphere, mesosphere and stratosphere. In this contribution we explore the long term changes of NO, both in volume mixing ratio and number density, and relate them to the responsible physical mechanisms, such as solar radiation and energetic particles. We further investigated the dynamical downward transport of NO from the lower thermosphere into the middle atmosphere during winter time conditions. These results are compared to the modelled NO output of the Whole Atmosphere Community Climate Model (WACCM) and plausible reasons for differences are discussed.