Comparisons of tropopause derived from COSMIC measurements at Nanjing since August 2006

• Tropopause properties at Nanjing are compared among the COSMIC, ESRL and NNR data sets since 2006.
• Tropopause temperature between the NNR and ESRL shows a warm bias in summer and a cold bias in winter.
• The tropopause properties of the NNR are significantly different from that of the COSMIC data.
• The ESRL and NNR ptpt and TtTt show a two-year period in terms of their correlation coefficients.

Tropopause temperature (TtTt) and pressure (ptpt) at Nanjing are derived from the Constellation Observing System for Meteorology, Ionosphere and Climate (COSMIC) from August 2006 to December 2011. We compareTtTtandptptamong the COSMIC, radiosonde provided by the Earth System Research Laboratory (ESRL) and reanalysis data sets from the National Centers for Environmental Prediction–National Center for Atmospheric Research (NCEP‐NCAR) Reanalysis (NNR) on 10-day, seasonal and annual timescales. Ten-day meanTtTt andptptof the COSMIC data are higher than that of radiosonde by 0.2 °C and 5.3 hPa and reanalysis by 1.0 °C and 17.5 hPa, respectively. Results of multiple comparisons demonstrate a significant difference forptptbetween the NNR and COSMIC data. Systematic biases are more significant in low-pressure level than in high-pressure level for reanalysis and radiosonde in terms of seasonal average differences. As for annual mean difference pressure, the COSMIC is higher than ESRL and NNR data by 3.4 hPa–6.5 hPa and 10 hPa, respectively. Besides, the COSMIC and other two data sets are in the best agreement forTtTtandptptwith maximum number of occultation events in 2008. Lastly, quasi-biennial period of correlation coefficients between the ESRL and NNR data sets from 2007 to 2011 requests further verification.