HadSLP2 (and HadSLP2r)

One-Line Description:

  • HadSLP2: gridded global SLP anomalies from 1850

Temporal Coverage:

  • Monthly values for 1850/01 to 2004/12 for HadSLP2
  • Monthly values for 1850/01 to present for HadSLP2r
  • Long term monthly means, derived from data for years 1971 - 2000

Spatial Coverage:

  • 5.0 degree latitude x 5.0 degree longitude global grid (72x37)
  • 90.0S - 90.0N, 0.0E - 355.0E


  • Sea Level

Update Schedule:

  • Monthly for HadSLP2r


Archive Parameters: (File names are composed of variable abbreviations and statistic name.)


Variable Abbreviation Level Download netCDF File
Sea Level Pressure Monthly mean Sea Level /Datasets.other/hadslp2/slp.mnmean.nc
Sea Level Pressure Monthly Climatology Sea Level /Datasets.other/hadslp2/slp.mon.ltm.nc
Sea Level Pressure, Real time Monthly mean Sea Level /Datasets.other/hadslp2/slp.mnmean.real.nc

Usage Restrictions:

  • Before acquiring Hadley SLP data from PSL: Please register with the Hadley Centre to help the Hadley Centre prove that their datasets are widely used in order to continue to get funding to maintain and improve them.

    Using Dataset: HadSLP2 is subject to Crown copyright protection. The material may be downloaded to file or printer for the purposes of private study and scientific research. Any other proposed use of the material is subject to a copyright license available from the Met Office.
    See http://hadobs.metoffice.com/gmslp/terms_and_conditions.html

Detailed Description:

  • HadSLP2 was created using marine observations taken from ICOADS (Worley et al 2005) and land (terrestrial and island) observations from 2228 stations around the globe. These land and marine observations were blended and the pressures reconstructed using a reduced-space optimal interpolation procedure, followed by superposition of quality-improved gridded observations onto the reconstructions to restore local detail.

    HadSLP2r was created by extending HadSLP2 to 2005, using monthly NCEP/NCAR data. These fields were then adjusted to account for the differences in climatological averages between the HadSLP2 and NCEP/NCAR products. For a detailed description of the dataset and its production process, see the paper reference below. The Hadley Center recommends you read this before using the data.


  • None

Related File Naming & Structure Information:

File Names:

  • var.time.stat.nc   (In directory: /Datasets.other/hadslp2/)
  • var.time.stat.real.nc    for the real time(In directory: /Datasets.other/hadslp2/)

Dataset Format and Size:

  • PSL standard NetCDF ~10 Mbyte file for each monthly file (packed).
  • PSL standard NetCDF 0.6 Mbyte file for the long term mean file (packed).

Missing Data:

  • None


  • For citing dataset use, see usage restrictions. Also cite

    Allan, R. J. and Ansell, T. J. (2006) 'A new globally complete monthly historical mean sea level pressure data set (HadSLP2): 1850-2004', Journal of Climate, (accepted)

  • Please note: If you acquire HadSLP2 data products from PSL, we ask that you acknowledge us in your use of the data. This may be done by including text such as HadSLP2 data provided by the NOAA/OAR/ESRL PSL, Boulder, Colorado, USA, from their Web site at / in any documents or publications using these data. We would also appreciate receiving a copy of the relevant publications. This will help PSL to justify keeping the HadSLP2 data set freely available online in the future. Thank you!


  • Allan, R., and T. Ansell, 2006: A New Globally Complete Monthly Historical Gridded Mean Sea Level Pressure Dataset (HadSLP2): 1850-2004. J. Climate, 19, 5816-5842.

Original Source:


  • Physical Sciences Laboratory: Data Management
    325 Broadway
    Boulder, CO 80305-3328