GC41H-02
Robust Comparison of Climate Models with Observations Using Blended Land Air and Ocean Sea Surface Temperatures
Thursday, 17 December 2015: 08:15
3001 (Moscone West)
Peter Jacobs, George Mason University, Environmental Science and Policy, Fairfax, VA, United States, Zeke Hausfather, University of California, Energy & Resources Group, Berkeley, CA, United States, Kevin Cowtan, University of York, York, United Kingdom, Ed Hawkins, University of Reading, Reading, United Kingdom, Michael E Mann, Pennsylvania State University Main Campus, University Park, PA, United States, Sonya K Miller, Penn State University, University Park, PA, United States, Byron A Steinman, University of Minnesota Duluth, Earth Sciences, Duluth, MN, United States, Robert G Way, University of Ottawa, Geography, Ottawa, ON, Canada and Martin Stolpe, ETH Zurich, Institute for Atmospheric and Climate Science, Zurich, Switzerland
Abstract:
Model-observation comparisons provide an important test of climate models' ability to realistically simulate the transient evolution of the system. A great deal of attention has recently focused on the so-called "hiatus" period of the past ~15 years, when estimates of recent surface temperature evolution fall at the lower end of climate model projections. This work quantifies a systematic bias in model-observation comparisons arising from differential warming rates between sea surface temperatures and surface air temperatures over oceans. Global mean temperatures from climate model simulations are typically calculated using surface air temperatures, while the corresponding observations are based on a blend of air and sea surface temperatures. A further bias arises from the treatment of temperatures in regions where the sea ice boundary has changed. We discuss the magnitude of these biases, and their implications for the evaluation of climate model performance over the "hiatus" period and the full instrumental record.
