Reanalysis Tropopause Data Repository

Introduction

This data repository provides access to tropopause parameters estimated from meteorological reanalyses. The tropopause data sets provided on this web site have been created using meteorological reanalyses distributed by the European Centre for Medium-Range Weather Forecasts (ECMWF), the Japanese Meteorological Agency (JMA), the National Aeronautics and Space Administration (NASA), and the National Centers for Atmospheric Prediction (NCEP).

Currently, the repository covers the following data sets:

• ECMWF ERA5 reanalysis (full resolution) for the years 2000 to 2023
• ECMWF ERA5 reanalysis (low resolution) for the years 1979 to 2023
• ECMWF ERA-Interim reanalysis for the years 1979 to 2019
• JMA JRA-3Q reanalysis for the years 1948 to 2024
• JMA JRA-55 reanalysis for the years 1958 to 2023
• NASA MERRA-2 reanalysis for the years 1980 to 2024
• NCEP-NCAR Reanalysis 1 for the years 1948 to 2024
• NCEP-DOE Reanalysis 2 for the years 1979 to 2024

The data are provided in form of daily netCDF files on a regular longitude-latitude grid and temporal sampling matching the native resolution of the corresponding reanalysis data sets. For ERA5 we provide a low-resolution version which has been downsampled to 1° x 1° horizontal resolution and 6-hourly synoptic time steps.

The tropopause data files include 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).

Two versions of the tropopause data sets are provided. Version 1 refers to the original data described by Hoffmann and Spang (2022). Version 2 applies the same algorithms for tropopause detection but includes surface pressure and height as well as ozone concentrations at the tropopause for further analysis.

Browse images

The browse images provided on this web site show time series of the various tropopause data sets. Use the navigation bars to select the tropopause definition and the parameter to be displayed. Click on an image to see the full-size version.

• Click here to access the browse images

Data access

All tropopause data sets are provided in daily netCDF files. The files are organized by reanalysis data set and year. You can download the files directly via your web browser or using the command line tools wget or curl.

• Click here to access and browse the data directories

The examples below show how to download all netCDF files for a given reanalysis and year (e.g., ERA5 low resolution tropopause data for the year 2000) from the repository:

# Using wget...
wget -r -nH -nd -np -e robots=off -A nc --no-check-certificate \
     https://datapub.fz-juelich.de/slcs/tropopause/data/v2/era5low/2000/

# Using curl...
curl -s https://datapub.fz-juelich.de/slcs/tropopause/data/v2/era5low/2000/ | \
  grep -oP 'href="[^"]+\.nc"' | cut -d'"' -f2 | \
  while read f; do
    curl -O https://datapub.fz-juelich.de/slcs/tropopause/data/v2/era5low/2000/$f
  done

The wget command will automatically download all files with the .nc extension from the specified directory. The curl alternative performs the same task using a shell loop. You may replace 2000 in the URL with another year or reanalysis data set as needed.

Data license

The data sets and browse images provided on this web site are licensed under a Creative Commons Attribution 4.0 International License.

You are free to share the material in any medium or format and adapt it for any purpose, even commercially, provided that appropriate credit is given, a link to the license is included, and any changes made are indicated. You may not apply legal terms or technological measures that legally restrict others from doing anything the license permits.

The data are distributed in the hope that they will be useful, but without any warranty. Please consult the full license text for details:

• Click here to view the license terms

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/10.3389/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.

Acknowledgement

This work was supported by the Deutsche Forschungsgemeinschaft (DFG; grant no. HO5102/1-1).

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