Estimation of the Absolute Surface Air Temperature of the Earth

TitleEstimation of the Absolute Surface Air Temperature of the Earth
Publication TypeJournal Article
Year of Publication2013
JournalJournal of Geophysical Research - Atmospheres
Number8
Pages3213–3217
Date Published04/2013
Abstract / Summary

Average temperatures for the hemispheres and the globe are generally expressed as anomalies from a base period. Most users of these data and the underlying constituent gridded datasets do not require the values in absolute degrees, but a number of users might require this additional detail. An example group of users are climate modelers, who want to directly compare their simulations with reality in absolute units. Reanalysis datasets offer opportunities of assessing earlier absolute temperature estimates, but until recently their quality over data-sparse regions of the world was questionable. Here, we assess the latest reanalysis (ERA-Interim) which is available from 1979 to the present against earlier direct estimates. Globally averaged ERA-Interim and the earlier direct estimates of absolute surface temperatures across the world are about 0.55°C different for the 1981–2010 period, with ERA-Interim cooler. The difference is only 0.29°C for the Northern Hemisphere, but larger at 0.81°C for the Southern Hemisphere. Spatially, the largest differences come from the Polar Regions, particularly the Antarctic.

DOI10.1002/jgrd.50359
Journal: Journal of Geophysical Research - Atmospheres
Year of Publication: 2013
Number: 8
Pages: 3213–3217
Date Published: 04/2013

Average temperatures for the hemispheres and the globe are generally expressed as anomalies from a base period. Most users of these data and the underlying constituent gridded datasets do not require the values in absolute degrees, but a number of users might require this additional detail. An example group of users are climate modelers, who want to directly compare their simulations with reality in absolute units. Reanalysis datasets offer opportunities of assessing earlier absolute temperature estimates, but until recently their quality over data-sparse regions of the world was questionable. Here, we assess the latest reanalysis (ERA-Interim) which is available from 1979 to the present against earlier direct estimates. Globally averaged ERA-Interim and the earlier direct estimates of absolute surface temperatures across the world are about 0.55°C different for the 1981–2010 period, with ERA-Interim cooler. The difference is only 0.29°C for the Northern Hemisphere, but larger at 0.81°C for the Southern Hemisphere. Spatially, the largest differences come from the Polar Regions, particularly the Antarctic.

DOI: 10.1002/jgrd.50359
Citation:
Jones, PD, and C Harpman.  2013.  "Estimation of the Absolute Surface Air Temperature of the Earth."  Journal of Geophysical Research - Atmospheres 3213–3217.  https://doi.org/10.1002/jgrd.50359.