IOD from NOAA NCDC ERSST version3b: In situ data: ICOADS2.5 before 2007, NCEP in situ data from 2008 to present. Ice data: HadISST ice before 2015 and NCEP ice after 2015..
Smith, T.M., R.W. Reynolds, Thomas C. Peterson, and Jay Lawrimore, 2008: Improvements to NOAA's Historical Merged Land-Ocean Surface Temperature Analysis (1880-2006). Journal of Climate, 21, 2283-2296.
Xue, Y., T. M. Smith, and R. W. Reynolds, 2003: Interdecadal changes of 30-yr SST normals during 1871-2000. J. Climate, 16, 1601-1612.