KlimaCampus Kolloquium: An Observational Estimate of the Pattern Effect on Climate Sensitivity
The "pattern effect" refers to the dependence of climate sensitivity on the spatial structure of temperature change. Most of the evidence for - and analyses of - the pattern effect is based on numerical experiments. Here I will explore key aspects of the pattern effect in observations.
The observational analyses focus on the relationships between the global-mean radiative response and spatially-varying variability in the surface temperature field. It is argued that the observational results provide a statistical analogue to the causal response functions derived from atmospheric models forced with surface temperature patches. Consistent with the feedbacks inferred from numerical experiments, the observational analyses indicate large negative internal feedbacks due to temperature variability over the western Pacific. Unlike the results inferred from such experiments, the analyses indicate equally large positive internal feedbacks over the southeastern tropical Pacific and negative internal feedbacks over land areas. When estimated from observations, temperature variability over the land areas accounts for roughly 80% of the global-mean, negative internal feedback; and temperature variability over the southeastern tropical Pacific acts to attenuate the global-mean negative internal feedback by nearly 10%. The talk will conclude with observational analyses of the causal factors that drive temperature variability over the southeastern tropical Pacific.
Datum
15.01.2026
Uhrzeit
15:15 h
Ort
- Bundesstr. 53, room 022/023
- Seminar Room 022/023, Ground Floor, Bundesstrasse 53, 20146 Hamburg, Hamburg