CoRea: Coupled reanalysis of the climate back to 1850

The CoRea is a "Young Research Talents" Project funded by the Research Council of Norway. 


The overall objective of CoRea is to produce a reliable three-dimensional coupled reanalysis of the climate from 1850 to present for studies on the role of the ocean in the climate system and climate variability at decadal to multi-decadal timescales.

The secondary objectives are

- to develop a novel multi-timescale ensemble smoother data assimilation technique.

- to preserve the efficacy of assimilation without introducing spurious variability.

- to identify mechanisms on how the low-frequency ocean variability influences climate variability.

Project Summary

In order to understand what drives climate variability and to better disentangle anthropogenic from natural variability, one mostly has to rely on climate model simulations. This is because observational data are sparse and not evenly distributed over time and geographically. Reanalysis provides a continuous three-dimensional reconstruction of climate variability by making best use of observational data to constrain model dynamics, using a mathematical method called data assimilation.

The project CoRea will produce a coupled reanalysis of high importance to the climate research community. The new reanalysis will come as a form of ensemble and provide a probabilistic estimate of the climate from 1850 to the present. Data assimilation will only update the ocean component of an Earth system model, and as a consequence the reanalysis will be of great importance to understand the role of the ocean in the rest of the climate system (e.g., the atmosphere and sea ice). The reanalysis will be the first one to use an advanced data assimilation method (Ensemble Kalman Smoother) that allows for model state updates varying with the regime of the climate and ensures the smoothness of the climate reconstruction. A theoretical methodology will be revisited to achieve the updates on several characteristic time scales of the climate. The new method will maximise the influence of the rich contemporary observations backwards in time for several decades. The project CoRea will be carried out by three early career researchers, which will foster the development of a new generation of climate researchers. CoRea will help to establish national interdisciplinary cooperation between NERSC, NORCE and UiB within the Bjerknes Centre for Climate Research, and to further build an internationally competitive group that operates at the forefront of climate research.

Project Details
Funding Agency: 
Research Council of Norway
NERSC Principal Investigator: 
Yiguo Wang
Coordinating Institute: 
Nansen Environmental and Remote Sensing Center
Project Status: