Forcings and chaos in interannual to decadal climate change
We investigate the roles of climate forcings and chaos in climate variability via a series of climate simulations for 1979-95 in which we add forcings one-by-one. Ensembles of simulations are carried out for a given forcing to allow study of predictability, chaos and significance. These experiments suggest that most interannual climate variability in the period 1979-95 at middle and high latitudes is chaotic, i.e., unforced. But observed SST anomalies account for much of the variability over land at low latitudes and a small portion of the variability at high latitudes. The radiative forcings, both natural and anthropogenic, leave clear signatures in the simulated climate change. Pinatubo aerosols warm the stratosphere and cool the surface globally, and in most places cause a tendency for regional surface cooling. Ozone depletion cools the lower stratosphere, troposphere and surface, steepening the temperature lapse rate in the troposphere. But the well-mixed anthropogenic greenhouse gases cause a surface warming which, over the 17 year time scale, more than offsets these cooling mechanisms. Observed stratospheric, tropospheric and surface temperatures reveal evidence of climate response to stratospheric aerosols, ozone depletion, and increasing greenhouse gases.
- OSTI ID:
- 577187
- Report Number(s):
- CONF-970522-; TRN: 98:000898-0019
- Resource Relation:
- Conference: 8. global warming international conference and expo, New York, NY (United States), 25-28 May 1997; Other Information: PBD: 1997; Related Information: Is Part Of 8th Global warming international conference and exposition; PB: 156 p.
- Country of Publication:
- United States
- Language:
- English
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