Climate Data

Merged Hadley-NOAA/OI Sea Surface Temperature & Sea-Ice Concentration (Hurrell et al, 2008)

The merged Hadley-OI sea surface temperature (SST) and sea ice concentration (SIC) data sets were specifically developed as surface forcing data sets for AMIP style uncoupled simulations of the Community Atmosphere Model (CAM). The Hadley Centre's SST/SIC version 1.1 (HADISST1), which is derived gridded, bias-adjusted in situ observations, were merged with the NOAA-Optimal Interpolation (version 2; OI.v2) analyses. The HADISST1 spanned 1870 onward but the OI.v2, which started in November 1981, better resolved features such as the Gulf Stream and Kuroshio Current which are important components of the climate system. Since the two data sets used different development methods, anomalies from a base period were used to create a more homogeneous record. Also, additional adjustments were made to the SIC data set.

Key Strengths:

  • Optimized as boundary conditions for atmospheric modeling; combines long, spatially complete global record with more resolution in recent decades
  • Regularly updated
  • Better resolution of Western Boundary Currents and other features in SSTs than HadISST

Key Limitations:

  • Sea ice suffers from discontinuities due to changes in source data (especially in SH); see HadISST and NOAA OI sea ice pages

Years of Record

1870/01 to 2016/03
temporal metadataID:




Data Time Period Extended?

yes, data set is extended

Spatial Resolution

1° x 1°

Ocean or Land

Ocean Only

Missing Data Flag

spatially complete

Vertical Levels

Input Data

HadISST 1870-Nov 1981; NOAA OI Dec 1981-present

Earth system components and main variables

Data Access: Please Cite data sources, following the data providers' instructions.

  1. Data Set in netCDF at NCAR Community Data Portal (user account required)
  2. ftp , cd archive/SSTICE , ls, prompt, get ... , quit

  1. Hurrell, J.W. et al (2008): A New Sea Surface Temperature and Sea Ice Boundary Dataset for the Community Atmosphere Model
  2. Rayner, N. A., et al (2003): Global analyses of sea surface temperature, sea ice, and night marine air temperature since the late nineteenth century. J. Geophys. Res., 108
  3. Reynolds, R. W, and T. M. Smith, 1994: Improved global sea surface tem- perature analyses using optimum interpolation. J. Climate, 7, 929–948.
  4. Folland, C. K., and D. E. Parker, 1995: Correction of instrumental biases in historical sea surface temperature data. Quart. J. Roy. Meteor. Soc., 121, 319–367

Key Figures

Click the thumbnails to view larger sizes



Sea ice concentration: Merged Had-OI Average Arctic sea ice concentration for March 2003-2007 from the Merged Had-OI boundary condition data set. (Figure by D. Schneider, NCAR).
Climate Data Guide Image Sample SST anomalies. The top two figures show two strong El Nino events for January (1983 and 1998) and two strong La Nina events (1974 and 2011). A 1950-79 climatology is used as a reference. (Climate Data Guide; D. Shea)

Cite this page

National Center for Atmospheric Research Staff (Eds). Last modified 03 Jun 2016. "The Climate Data Guide: Merged Hadley-NOAA/OI Sea Surface Temperature & Sea-Ice Concentration (Hurrell et al, 2008)." Retrieved from

Acknowledgement of any material taken from this page is appreciated. On behalf of experts who have contributed data, advice, and/or figures, please cite their work as well.