UWM Math Colloquium

Friday, November 30, 2007, 1:00 PM, EMS EMS W434

Chris Spannagle, M.S. Defense

Under the Supervision of Sergey Kravtsov

Atmospheric Sciences Group

University of Wisconsin-Milwaukee, 2007

Multi-decadal climate variability in observed and modeled surface temperatures

Abstract:

This study identifies interdecadal natural climate variability in global surface temperatures by subtracting, from the observed temperature evolution, multi-model ensemble mean based on the World Climate Research Programme's (WCRP's) Coupled Model Intercomparison Project phase 3 (CMIP3) multi-model dataset. The resulting signal resembles the so-called Atlantic Multidecadal Oscillation (AMO) and is presumably associated with intrinsic dynamics of the oceanic thermohaline circulation (THC). While certain phases of the oscillation are dominated by the anomalies in the North Atlantic region, other phases are characterized by global teleconnections to the North Pacific Ocean, Tropical Atlantic Ocean, as well as to the Southern Ocean. In particular, natural variability of sea-surface temperature in the Atlantic hurricanes’ main development region has a peak-to-peak amplitude comparable in magnitude to this region’s surface temperature increase over the past century, for all seasons. Evidence suggests that the AMO influence on secular trends in the global-mean surface temperature can arise via direct, regional, contribution to the surface temperature evolution, as well as via indirect route linked to variability of the oceanic uptake of CO2 associated with AMO-related THC changes.

Refreshments: 12:30 pm, EMS W434