Publication Abstracts

Hansen et al. 2001

Hansen, J.E., R. Ruedy, M. Sato, M. Imhoff, W. Lawrence, D. Easterling, T. Peterson, and T. Karl, 2001: A closer look at United States and global surface temperature change. J. Geophys. Res., 106, 23947-23963, doi:10.1029/2001JD000354.

We compare the United States and global surface air temperature changes of the past century using the current Goddard Institute for Space Studies (GISS) analysis and the U.S. Historical Climatology Network (USHCN) record [Karl et al., 1990]. Changes in the GISS analysis subsequent to the documentation by Hansen et al. [1999] are as follows: (1) incorporation of corrections for time-of-observation bias and station history adjustments in the United States based on Easterling et al. [1996a], (2) reclassification of rural, small-town, and urban stations in the United States, southern Canada, and northern Mexico based on satellite measurements of night light intensity [Imhoff et al., 1997], and (3) a more flexible urban adjustment than that employed by Hansen et al. [1999], including reliance on only unlit stations in the United States and rural stations in the rest of the world for determining long-term trends. We find evidence of local human effects ("urban warming") even in suburban and small-town surface air temperature records, but the effect is modest in magnitude and conceivably could be an artifact of inhomogeneities in the station records. We suggest further studies, including more complete satellite night light analyses, which may clarify the potential urban effect. There are inherent uncertainties in the long-term temperature change at least of the order of 0.1°C for both the U.S. mean and the global mean. Nevertheless, it is clear that the post-1930s cooling was much larger in the United States than in the global mean. The U.S. mean temperature has now reached a level comparable to that of the 1930s, while the global temperature is now far above the levels earlier in the century. The successive periods of global warming (1900-1940), cooling (1940-1965), and warming (1965-2000) in the 20th century show distinctive patterns of temperature change suggestive of roles for both climate forcings and dynamical variability. The U.S. was warm in 2000 but cooler than the warmest years in the 1930s and 1990s. Global temperature was moderately high in 2000 despite a lingering La Niña in the Pacific Ocean.

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BibTeX Citation

  author={Hansen, J. E. and Ruedy, R. and Sato, M. and Imhoff, M. and Lawrence, W. and Easterling, D. and Peterson, T. and Karl, T.},
  title={A closer look at United States and global surface temperature change},
  journal={Journal of Geophysical Research},

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RIS Citation

ID  - ha02300a
AU  - Hansen, J. E.
AU  - Ruedy, R.
AU  - Sato, M.
AU  - Imhoff, M.
AU  - Lawrence, W.
AU  - Easterling, D.
AU  - Peterson, T.
AU  - Karl, T.
PY  - 2001
TI  - A closer look at United States and global surface temperature change
JA  - J. Geophys. Res.
JO  - Journal of Geophysical Research
VL  - 106
SP  - 23947
EP  - 23963
DO  - 10.1029/2001JD000354
ER  -

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