HR: 1020h
AN: PP52A-0664    [Abstracts]
TI: Comparison of Observations With Climate Models
AU: * Douglass, d h
EM: douglass@pas.rochester.edu
AF: University of Rochester, River Campus Station, Rochester, NY 14627 United States
AU: singer, s f
EM: singer@sepp.org
AF: Science & Environmental Policy ProjectPolicy Project, 1600 S. Eads St, #712-S , Arlington, Va 22202 United States
AB: A key problem is to establish the extent of the human contribution to climate change, especially in the past 25 years. This task involves the careful comparison of observations of surface (from land and oceans) and troposphere (from radiosondes and satellites) temperatures with climate models that incorporate all relevant forcings, including those from rising levels of greenhouse gases. Unfortunately, uncertainties are still very large. Modeled climate sensitivities can range from about 1.5 C up to 11.5 C (for a doubling of CO2) depending on details of parameterization of clouds [Stainforth et al]. We will discuss the disparities reported for observed temperature trends from the MSU satellite data by the UAH [Christy, Spencer] and RSS [Mears, Wentz] groups and the ongoing corrections of radiosonde trends [Sherman et al], and describe efforts for their resolution [Thorne et al]. A concordance of temperature trends for surface and troposphere is a necessary but not sufficient condition; it seems to exist for short-term climate fluctuations but not on a decadal scale [Santer et al 2005]. The latitude variation of temperature trends does not accord with models - esp. in the Arctic and Antarctic. Also, the observed dependence of trends does not match what models predict [Douglass, Pearson, Singer]. It would be premature therefore to claim that observations and greenhouse models agree and that most or all of recent warming is anthropogenic.
DE: 1600 GLOBAL CHANGE
DE: 1610 Atmosphere (0315, 0325)
DE: 1616 Climate variability (1635, 3305, 3309, 4215, 4513)
DE: 1626 Global climate models (3337, 4928)
DE: 1630 Impacts of global change (1225)
SC: Paleoceanography and Paleoclimatology [PP]
MN: Fall Meeting 2005