Deconstructing interdecadal climate variability using a network of paleoclimate proxy records

Abstract:

Interdecadal climate variability is of marked socioeconomic importance around the world and recent studies suggest that it may also affect the rate of global warming (Here, interdecadal variability refers broadly to variability on time scales of 10-100 years.) Our understanding of interdecadal climate variability is at present limited by a short instrumental record constituting only a few cycles. To improve climate prediction over the coming decades, a better understanding of interdecadal climate variability is critical. An increasing number of annually resolved paleoclimate proxy records present a means to extend the temporal coverage of the record of interdecadal variability. In so doing, we may begin to address the following questions. What were the amplitudes and timescales of known modes of interdecadal variability, such as the Interdecadal Pacific Oscillation (IPO) or the Atlantic Multidecadal Oscillation (AMO), before the instrumental era? Is interdecadal variability in different ocean basins related? Are there any yet undiscovered modes of interdecadal variability? To answer these questions we construct a network of annually-resolved proxy records collected from the NOAA paleoclimatology data archive and perform various statistical analyses without any a priori assumptions about modes of variability. During the instrumental period, this network reasonably captures the observed interdecadal variability in the Atlantic and Pacific Oceans. We are currently extending these analyses beyond the instrumental record to reconstruct past variability. The new insight gained from the proxies will be assessed through the analysis of CMIP5 climate model simulations.