Abstract
Long term data of auroral ray heights according to Störmer's measurements have been analyzed. Also the data of measurements of the lower border of auroral arcs during the second part of the 20th century have been used. The mean regular seasonal and solar activity variations have been removed from the measured data. The result reveals a long term linear negative trend of mean auroral heights (−0.8 km/yr and −0.5 km/yr) at heights 160–180 km during the period from 1918 till 1944 and 145 km for the period from 1957 till 1988, respectively. There is satisfactory agreement with the atmospheric subsidence for the periods 1918–1944 and 1955–1995. Thus, there was a stable process of middle and upper atmospheric cooling and subsidence over the 20 th century.
Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
