What complexity PSM for paleoclimate data assimilation? Results from a tree-ring width data model intercomparison study

Abstract:

Proxy system models (PSMs) map from environmental fields to paleoclimatic observables, enabling data assimilation, but the extent to which more realistic representation of proxy systems improve the results is not yet clear. Via manipulative experiments, data model intercomparison projects (DMIPs) can illustrate and validate presumed PSM complexity, filtering and applicability across archives and space. We describe an experiment to identify the appropriate level of sensor model complexity for a small set of tree ring width chronologies that span eight combinations of mean climatic regime and sensitivity to either moisture or temperature limitation, as determined by linear regression analysis. In this contribution, the performance of tree-ring width simulations using Vaganov-Shashkin (VS-Lite, VS), MAIDEN, and ORCHIDEE intermediate to high complexity sensor models will be performed and compared to that obtained from the linear bivariate statistical modeling. Unified platforms for developing DMIPs could facilitate more comprehensive studies and thereby advances in the use of PSMs for paleoclimatic data assimilation exercises.