Publication Abstracts

Hansen et al. 1997

Hansen, J., M. Sato, R. Ruedy, A. Lacis, K. Asamoah, K. Beckford, S. Borenstein, E. Brown, B. Cairns, B. Carlson, B. Curran, S. de Castro, L. Druyan, P. Etwarrow, T. Ferede, M. Fox, D. Gaffen, J. Glascoe, H. Gordon, S. Hollandsworth, X. Jiang, C. Johnson, N. Lawrence, J. Lean, J. Lerner, K. Lo, J. Logan, A. Luckett, M.P. McCormick, R. McPeters, R.L. Miller, P. Minnis, I. Ramberran, G. Russell, P. Russell, P. Stone, I. Tegen, S. Thomas, L. Thomason, A. Thompson, J. Wilder, R. Willson, and J. Zawodny, 1997: Forcings and chaos in interannual to decadal climate change. J. Geophys. Res., 102, 25679-25720, doi:10.1029/97JD01495.

We investigate the roles of climate forcings and chaos (unforced variability) in climate change via ensembles of climate simulations in which we add forcings one by one. The experiments suggest that most interannual climate variability in the period 1979-1996 at middle and high latitudes is chaotic. But observed SST anomalies, which themselves are partly forced and partly chaotic, account for much of the climate variability at low latitudes and a small portion of the variability at high latitudes. Both a natural radiative forcing (volcanic aerosols) and an anthropogenic forcing (ozone depletion) leave clear signatures in the simulated climate change that are identified in observations. Pinatubo aerosols warm the stratosphere and cool the surface globally, causing a tendency for regional surface cooling. Ozone depletion cools the lower stratosphere, troposphere and surface, steepening the temperature lapse rate in the troposphere. Solar irradiance effects are small, but our model is inadequate to fully explore this forcing. Well-mixed anthropogenic greenhouse gases cause a large surface warming that, over the 17 years, approximately offsets cooling by the other three mechanisms. Thus the net calculated effect of all measured radiative forcings is approximately zero surface temperature trend and zero heat storage in the ocean for the period 1979-1996. Finally, in addition to the four measured radiative forcings, we add an initial (1979) disequilibrium forcing of +0.65 W/m2. This forcing yields a global surface warming of about 0.2°C over 1979-1996, close to observations, and measureable heat storage in the ocean. We argue that the results represent evidence of a planetary radiative imbalance of at least 0.5 W/m2; this disequilibrium presumably represents unrealized warming due to changes of atmospheric composition prior to 1979. One implication of the disequilibrium forcing is an expectation of new record global temperatures in the next few years. The best opportunity for observational confirmation of the disequilibrium is measurement of ocean tempreatures adequate to define heat storage.

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BibTeX Citation

  author={Hansen, J. and Sato, M. and Ruedy, R. and Lacis, A. and Asamoah, K. and Beckford, K. and Borenstein, S. and Brown, E. and Cairns, B. and Carlson, B. and Curran, B. and de Castro, S. and Druyan, L. and Etwarrow, P. and Ferede, T. and Fox, M. and Gaffen, D. and Glascoe, J. and Gordon, H. and Hollandsworth, S. and Jiang, X. and Johnson, C. and Lawrence, N. and Lean, J. and Lerner, J. and Lo, K. and Logan, J. and Luckett, A. and McCormick, M. P. and McPeters, R. and Miller, R. L. and Minnis, P. and Ramberran, I. and Russell, G. and Russell, P. and Stone, P. and Tegen, I. and Thomas, S. and Thomason, L. and Thompson, A. and Wilder, J. and Willson, R. and Zawodny, J.},
  title={Forcings and chaos in interannual to decadal climate change},
  journal={J. Geophys. Res.},

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RIS Citation

ID  - ha09000a
AU  - Hansen, J.
AU  - Sato, M.
AU  - Ruedy, R.
AU  - Lacis, A.
AU  - Asamoah, K.
AU  - Beckford, K.
AU  - Borenstein, S.
AU  - Brown, E.
AU  - Cairns, B.
AU  - Carlson, B.
AU  - Curran, B.
AU  - de Castro, S.
AU  - Druyan, L.
AU  - Etwarrow, P.
AU  - Ferede, T.
AU  - Fox, M.
AU  - Gaffen, D.
AU  - Glascoe, J.
AU  - Gordon, H.
AU  - Hollandsworth, S.
AU  - Jiang, X.
AU  - Johnson, C.
AU  - Lawrence, N.
AU  - Lean, J.
AU  - Lerner, J.
AU  - Lo, K.
AU  - Logan, J.
AU  - Luckett, A.
AU  - McCormick, M. P.
AU  - McPeters, R.
AU  - Miller, R. L.
AU  - Minnis, P.
AU  - Ramberran, I.
AU  - Russell, G.
AU  - Russell, P.
AU  - Stone, P.
AU  - Tegen, I.
AU  - Thomas, S.
AU  - Thomason, L.
AU  - Thompson, A.
AU  - Wilder, J.
AU  - Willson, R.
AU  - Zawodny, J.
PY  - 1997
TI  - Forcings and chaos in interannual to decadal climate change
JA  - J. Geophys. Res.
VL  - 102
SP  - 25679
EP  - 25720
DO  - 10.1029/97JD01495
ER  -

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