Resolution and Frequency-Dependent Climate Signals in an Arctic Tree-Ring Temperature Reconstruction of the Last Millennium

Paleoclimatology makes it possible to place recent climate changes in a longer-term context than is available from the instrumental record. Tree-ring reconstructions, often used to quantify temperature variations over the Common Era, contain multiple uncertainties that affect estimates of the magnitude of recent trends and past variability. The use of maximum latewood density (MXD) proxy mitigates many biases, but intra-annual measurement resolution remains a limitation. We develop a quantitative wood anatomy (QWA)-based temperature reconstruction from the Firth River in northeastern Alaska from 1150 CE to 2021 CE to improve regional past temperature estimates and to test the sensitivity of MXD-based climate reconstructions to measurement constraints. We find that high-resolution wood-anatomy measurements reduce biological noise and enhance the representation of low-frequency variability, resulting in stronger temperature signals and a larger magnitude of preindustrial to modern change. QWA data provide novel high-resolution information that improves tree-ring temperature reconstructions.