PRYSM: open-source tools for PRoxY System Modeling v1.0: oxygen-isotope systems

Proxy system modeling can be used in paleoclimatology to improve the interpretation of paleoclimate data. Existing forward models for climate proxies are somewhat scattered in the literature, making their integration difficult. Further, each model has been coded separately, according to disparate conventions. Here, we present a comprehensive, consistently formatted package of forward models for water-isotope based climate proxies (ice cores, corals, tree ring cellulose, and speleothem calcite) [PRYSM]. This suite of Python-scripted models requires a standard set of climate inputs and can be used to simulate the proxy variable of interest by proxy class. By making this forward modeling toolbox publicly available, PRYSM provides an accessible platform that maximizes the utility of proxy data and facilitates proxy-climate (simulated or historical) comparisons. Many of these codes have been employed in past studies; we review modeling approaches for each proxy class, and compare results when forced with an isotope-enabled climate simulation. Applications of multi-proxy forward modeling including parameter estimation, the effects of physical processes (such as karst transit times or firn diffusion in ice cores) on the simulated climate signal, as well as explicit modeling of time uncertainties are used to demonstrate the utility of PRYSM for a broad array of climate studies.