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Radiosonde Atmospheric Temperature Products for Assessing Climate (RATPAC)

Photo of Army Air Force meteorologists preparing to launch a weather balloon

Army Air Force meteorologists prepare to launch a hydrogen-filled balloon that will carry a radiosonde up in the air to measure temperature, humidity, and atmospheric pressure and transmit the data back to a ground station. Courtesy of the NOAA Photo Library.

The Radiosonde Atmospheric Temperature Products for Assessing Climate (RATPAC) consist of time series of radiosonde-based temperature anomalies for the years 1958-present in which the temporal inhomogeneities resulting from changes in instruments and observing practices have been reduced to the extent possible. NOAA scientists recommend that RATPAC be used for the assessment of long-term changes in tropospheric and lower-stratospheric temperatures on large spatial scales. Developed by NOAA scientists in the early 2000s, the RATPAC time series are based on data from 85 stations distributed around global land areas and are available on 13 atmospheric pressure levels between the Earth's surface and lower stratosphere. For other uses of radiosonde data, please referred to the Integrated Global Radiosonde Archive (IGRA).

Current Version

The current version of RATPAC is Version 2. The difference between this version and the original version of RATPAC is that the IGRA component of Version 2 originates from IGRA v2 rather than IGRA v1. for the latest information on the status of RATPAC, see the status file. To receive email notifications regarding changes to RATPAC, please register online using this Optional Registration Form.

RATPAC Components

RATPAC consists of two products, each derived using a different approach:

RATPAC-A contains adjusted global, hemispheric, tropical, and extratropical mean temperature anomalies. From 1958 through 1995, the bases of the data are spatial averages of the Lanzante et al. (2003a,b; hereafter LKS) adjusted 87-station temperature data. After 1995, the Integrated Global Radiosonde Archive (IGRA) station data form the basis of the RATPAC-A data. NOAA scientists used the so-called "first difference method"; to combine the IGRA data. This method is intended to reduce the influence of inhomogeneities resulting from changes in instrumentation, observing practice, or station location. Use RATPAC-A for analyses of interannual and longer-term changes in global, hemispheric, and tropical means.

RATPAC-B contains data for individual stations as well as large-scale arithmetic averages corresponding to areas used for RATPAC-A. The station data consist of adjusted data produced by LKS for the period 1958–1997 and unadjusted data from IGRA after 1997. The regional mean time series in RATPAC-B represent arithmetic averages of these station data. Use RATPAC-B for studying long-term temperature changes in monthly data or over smaller regions than is possible with RATPAC-A, albeit with careful attention to the potential of inhomogeneities influencing the analysis after 1997.

RATPAC Updates

NCEI scientists recalculate the RATPAC time series once a month on the sixth day of the month.

Download RATPAC Data

Please review the readme file prior to downloading the data as it describes contents, format, and location of each RATPAC files. Both RATPAC-A and RATPAC-B are available at the below FTP and HTTP links.

  • FTP
    Use an FTP interface to download ASCII versions of the RATPAC data from our access area.
  • HTTP
    Use your browser to download ASCII versions of the RATPAC data from our access area.

Additional Information

For additional information about RATPAC, see the following references:

  • Free M., D.J. Seidel, J.K. Angel, J. Lanzante, I. Durre and T.C. Peterson, 2005: Radiosonde Atmospheric Temperature Products for Assessing Climate (RATPAC): A new dataset of large-area anomaly time series. Journal of Geophysical Research, 110, D22101, http://dx.doi.org/10.1029/2005JD006169.
    A Comprehensive Overview of RATPAC.
  • Free, M., J. K. Angell, I. Durre, J. R. Lanzante, T. C. Peterson, and D. J. Seidel, 2004: Using first differences to reduce inhomogeneity in radiosonde temperature datasets. Journal of Climate, 17, 4171-4179 http://journals.ametsoc.org/doi/full/10.1175/JCLI3198.1.
    Paper describing the application of the first difference method to radiosonde temperature anomalies.
  • Lanzante, J. R., S. A. Klein, and D. J. Seidel, 2003a: Temporal homogenization of monthly radiosonde temperature data. Part I: Methodology. Journal of Climate, 16, 224-240.
    The first of two references describing the LKS time series.
  • Lanzante, J. R., S. A. Klein, and D. J. Seidel, 2003b: Temporal homogenization of monthly radiosonde temperature data. Part II: Trends, sensitivities, and MSU comparison. Journal of Climate, 16, 241-262 http://dx.doi.org/10.1175/1520-0442(2003)016<0241:THOMRT>2.0.CO;2.
    The Second of two references describing the LDS time series.

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