Resolving the differences in the simulated and reconstructed climate
response to volcanism over the last millennium
Abstract
Explosive volcanism imposes impulse-like radiative forcing on the
climate system, providing a natural setting to study the climate
response to perturbation. Previous studies have identified disagreements
between paleoclimate reconstructions and climate model simulations
(GCMs) with respect to the magnitude and recovery from volcanic cooling,
questioning the fidelity of GCMs, reconstructions, or both. Using the
paleoenvironmental data assimilation framework of the Last Millennium
Reanalysis, this study investigates the causes of the disagreements,
using both real and simulated data. We demonstrate that the disagreement
may be resolved by assimilating tree-ring density records only, by
targeting growing-season temperature instead of annual temperature, and
by performing the comparison at proxy locales. Our work suggests that
discrepancies between paleoclimate models and data can be largely
resolved by accounting for these features of tree-ring proxy networks.