Publications
Following publications have been announced by our Institute of Coastal Systems – Analysis and Modeling. For further information please contact Prof Dr Hans von Storch, author and co-author of the publications:
Lin, L., von Storch, H., & Chen, X. (2023): The Stochastic Climate Model helps reveal the role of memory in internal variability in the Bohai and Yellow Sea. Commun Earth Environ 4, 347, doi:10.1038/s43247-023-01018-7
Abstract:
Hasselmann’s theory elucidates how short-term random noise leads to longer-term unprovoked variations, i.e., red spectra. Here, we study ensembles of numerical model simulations of the hydrodynamics of the Bohai and Yellow Sea concerning internal variability formation. Short(/long) term variations are associated with small(/large) spatial scales, and the internal variability of long-term temporal and large-scale variations is markedly enhanced, even without external forcing on these scales, when the tides are turned off. This pattern is well explained by Hasselmann’s theory. A critical element in this theory is the concept of memory, which in our ensembles exhibits a scale dependence that aligns with the scale-dependent nature of redness. Additionally, this framework clarifies why there is a significant reduction of long-term fluctuations during winter and when tides are active: the system’s memory is notably diminished under these conditions.
Additional background information for above mentioned publication:
von Storch, H., Chen, X., & Lin, L. (2023): Hasselmann reloaded: internal variability in marginal seas. Behind the paper, Springer Nature Blog, https://go.nature.com/46rBrlg
Summary:
In 1976, Klaus Hasselmann initiated a groundbreaking shift in climate science when he introduced the Stochastic Climate Model (SCM) to the field, a conceptual framework aimed at elucidating the origins of red spectra observed in the dynamics of both the atmosphere and the oceans. While this concept had somewhat faded from the limelight as climate science increasingly morphed into climate change science, it regained prominence within the climate science community when Klaus Hasselmann was awarded the Nobel Prize in Physics in 2021.
Historically, the primary use of the SCM centered on explaining why the spectra of atmospheric and oceanic dynamics were continuous and “red“ rather than a series of peaks. Our present paper has expanded the scope of the SCM’s applicability, when we used it as a valuable tool for understanding the generation of intrinsic variability (often referred to as “noise“) within the hydrodynamics of a marginal sea. Our analysis of multiple simulation ensembles using a regional ocean model has uncovered a relationship between the generation of intrinsic variability tied to the annual cycle and the activation of tides. This relationship can be attributed to a single parameter, and notably, this parameter corresponds to the central element in the SCM—referred to as the „memory.“
