# Monthly mean zonal mean reanalysis tropopause data sets ## Overview This directory contains monthly mean zonal mean tropopause data sets derived from various meteorological reanalyses. Currently the following reanalysis data sets are included: - ECMWF ERA5 reanalysis (full resolution) for the years 2000 to 2022 - ECMWF ERA5 reanalysis (low resolution) for the years 1979 to 2022 - ECMWF ERA-Interim reanalysis for the years 1979 to 2019 - NASA MERRA-2 reanalysis for the years 1980 to 2022 - NCEP-NCAR Reanalysis 1 for the years 1948 to 2022 - NCEP-DOE Reanalysis 2 for the years 1979 to 2022 The monthly mean zonal mean data files provide geopotential height, pressure, temperature, water vapor, and ozone volume mixing ratio for the first and second thermal lapse rate tropopause (WMO definition), the cold point (local temperature minimum), and the dynamical tropopause (380 K potential temperature in the tropics and 3.5 potential vorticity units in the extratropics). The data are provided as monthly ASCII files containing the mean and standard deviation (sigma) of the tropopause parameters. The data are provided on the latitude grids corresponding to the native resolutions of the reanalyses. For ERA5, we also provide a low resolution data set downsampled to 1° x 1° horizontal resolution and 6-hourly synoptic time steps. The monthly mean zonal mean data files use the following filename convention: .//___.tab For reference, time series plots of the data can be found in the ./plots directory. ## References Citations, if the data are used in publications: Hoffmann, L. and Spang, R.: An assessment of tropopause characteristics of the ERA5 and ERA-Interim meteorological reanalyses, Atmos. Chem. Phys., 22, 4019-4046, https://doi.org/10.5194/acp-22-4019-2022, 2022. Zou, L., Hoffmann, L., Müller, R. and Spang. R., Variability and trends of the tropical tropopause derived from a 1980–2021 multi-reanalysis assessment, Front. Earth Sci., 11:1177502, https://doi.org/10.5194/10.3389/feart.2023.1177502, 2023. This data repository can be cited as: Hoffmann, L. and R. Spang, Reanalysis Tropopause Data Repository, https://doi.org/10.26165/JUELICH-DATA/UBNGI2, Jülich DATA, V1, 2021. ## Contact Please do not hesitate to contact us if you have any questions regarding the use of the data set: Dr. Lars Hoffmann Forschungszentrum Jülich Jülich Supercomputing Centre 52425 Jülich Germany e-mail: l.hoffmann@fz-juelich.de