Stochastic Parameterization: Toward a New View of Weather and Climate Models

TLDR

Stochastic parameterizations have become standard in weather forecasting, improving uncertainty quantification and showing promise for reducing climate biases and better assessing climate responses to external forcing. The article aims to highlight recent developments demonstrating that stochastic representations of unresolved processes across atmospheric, oceanic, land, and cryospheric components yield more reliable probabilistic forecasts and reduce systematic bias. The authors review mathematically rigorous derivations of stochastic dynamic equations from mathematics, statistical mechanics, and turbulence, arguing that such methods will enhance simulation accuracy across all scales. Recent work in mathematics, statistical mechanics, and turbulence is reviewed, its relevance for the climate problem demonstrated, and future research directions outlined.

Abstract

The last decade has seen the success of stochastic parameterizations in short-term, medium-range and seasonal forecasts: operational weather centers now routinely use stochastic parameterization schemes to better represent model inadequacy and improve the quantification of forecast uncertainty. Developed initially for numerical weather prediction, the inclusion of stochastic parameterizations not only provides better estimates of uncertainty, but it is also extremely promising for reducing longstanding climate biases and relevant for determining the climate response to external forcing. This article highlights recent developments from different research groups which show that the stochastic representation of unresolved processes in the atmosphere, oceans, land surface and cryosphere of comprehensive weather and climate models (a) gives rise to more reliable probabilistic forecasts of weather and climate and (b) reduces systematic model bias. We make a case that the use of mathematically stringent methods for the derivation of stochastic dynamic equations will lead to substantial improvements in our ability to accurately simulate weather and climate at all scales. Recent work in mathematics, statistical mechanics and turbulence is reviewed, its relevance for the climate problem demonstrated, and future research directions outlined.