"Hemispheric and large-scale land-surface air temperature variations: An extensive revision and an update to 2010" by Phil D. Jones et al., JGR 117 (2012) doi:10.1029/2011JD017139

Journal of Geophysical Research, 117 (2012) D05127; doi:10.1029/2011JD017139


Hemispheric and large-scale land-surface air temperature variations: An extensive revision and an update to 2010


P. D. Jones, D. H. Lister, T. J. Osborn, C. Harpham, M. Salmon and C. P. Morice


Received 8 November 2011, revised 17 January 2012, accepted 17 January 2012, published 14 March 2012.


Abstract

[1] This study is an extensive revision of the Climatic Research Unit (CRU) land station temperature database that has been used to produce a grid-box data set of 5 latitude 5  longitude temperature anomalies. The new database (CRUTEM4) comprises 5,583 station records of which 4,842 have enough data for the 1961–1990 period to calculate or estimate the average temperatures for this period. Many station records have had their data replaced by newly homogenized series that have been produced by a number of studies, particularly from National Meteorological Services (NMSs). Hemispheric temperature averages for land areas developed with the new CRUTEM4 data set differ slightly from their CRUTEM3 equivalent. The inclusion of much additional data from the Arctic (particularly the Russian Arctic) has led to estimates for the Northern Hemisphere (NH) being warmer by about 0.1 C for the years since 2001. The NH/Southern Hemisphere (SH) warms by 1.12 C/0.84 C over the period 1901–2010. The robustness of the hemispheric averages is assessed by producing five different analyses, each including a different subset of 20% of the station time series and by omitting some large countries. CRUTEM4 is also compared with hemispheric averages produced by reanalyses undertaken by the European Centre for Medium-Range Weather Forecasts (ECMWF): ERA-40 (1958–2001) and ERA-Interim (1979–2010) data sets. For the NH, agreement is good back to 1958 and excellent from 1979 at monthly, annual, and decadal

time scales. For the SH, agreement is poorer, but if the area is restricted to the SH north of 60 S, the agreement is dramatically improved from the mid-1970s.

Citation: Jones, P. D., D. H. Lister, T. J. Osborn, C. Harpham, M. Salmon, and C. P. Morice (2012). Hemispheric and large-scale land-surface air temperature variations: An extensive revision and an update to 2010, J. Geophys. Res., 117, D05127, doi:10.1029/2011JD017139.