Homogenized monthly upper‐air temperature data set for Australia

Abstract

ABSTRACTWe present a homogenized, monthly, upper‐air temperature data set comprising 22 stations across the Australian continent, as well as five Australian remote island sites. The data set is based on 2300 UTC radiosonde soundings, with most records starting in 1958. The data are mostly complete since that time, with missing data more frequent at higher levels. The quality control process involved the examination of station metadata and an objective statistical test to detect discontinuities in the data, for which monthly temperature series were adjusted. Homogenized temperature data were analysed at standard levels. The all‐Australian annual mean temperature shows statistically significant trends over the 1958–2011 period, larger than the trends in surface temperature. Over this period, the annual 850 and 700 hPa mean temperatures show positive trends of 0.21 and 0.16 °C decade−1, respectively, more than the surface temperature which shows positive trend of 0.12 °C decade−1. Mid‐troposphere (the 500, 400 and 300 hPa levels) also shows positive trends of 0.13, 0.15 and 0.20 °C decade−1, respectively. Trends are small and of reverse sign at levels that intercept the tropopause: +0.08 °C decade−1 at 200 hPa and −0.14 °C decade−1 at 150 hPa. In the lower stratosphere (at 100 hPa), temperature trend is strongly negative, −0.39 °C decade−1. A similar vertical structure in the trends was found for the remote islands. The homogenized upper‐air radiosonde records for the Australian region are an independent confirmation of the expected physical response to increased atmospheric greenhouse gas concentrations: (1) a general warming in the troposphere, (2) a cooling in the lower stratosphere and (3) a faster warming of the troposphere than the surface.