Monthly and zonally averaged tropopause heights for the globe derived by W.J. Randel are available on CEDA and can be accessed anonymously via:
Please use an ftp client such as FileZilla to connect to the ftp server as many browsers, including chrome, no longer support urls using the ftp protocol. See the README file for further information.
Randel, W.J., F. Wu and D. Gaffen (2000), Interannual variability of the tropical tropopause derived from radiosonde data and NCEP reanalyses. J. Geophys. Res., 105, 15509-15523, doi:10.1029/2000JD900155.