An observational analysis of Southern Hemisphere tropical expansion

摘要: [1] Historical radiosonde data are analyzed using the tropopause height frequency method to investigate variation of Southern Hemisphere tropical edge from 1979/80–2010/11, independently reanalysis-derived data. Averaged across hemisphere we identify a expansion trend 0.41 ± 0.37 deg dec−1, significant at 90% level. A comparison with four reanalyses shows generally consistent results between radiosondes and reanalyses. Estimated rates in SH broadly similar, as is interannual variability. However, notable differences remain. Some these related methodology used reanalyses, which produces inconsistent subtropics. Differences also more manifest data-poor regions. In regions, not fully constrained, allowing internal model dynamics drive The performance varies temporally compared These particularly apparent 1979 1985 2001 2010. latter period, hypothesize that increased availability quality satellite-based improves ERA Interim reanalysis, creating an inconsistency earlier This inhomogeneity product radiosonde-based observations. confirm need for careful evaluation reanalysis-based use studies long-term climate